Human Biology
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
Tissues of the Skeletal System
A system is made up of organs, and every organ is made up of tissues. The organs referred to
as bones are largely composed of connective tissue, especially bone, cartilage, and fibrous
connective tissue. In a long bone, hyaline (articular) cartilage covers the ends, while periosteum
(fibrous connective tissue) covers the rest of the bone. Spongy bone, which may contain red bone
marrow, is in the epiphyses, while yellow bone marrow is in the medullary cavity of the
diaphysis. The wall of the diaphysis is compact bone.
Bone Growth and Repair
Bone is a living tissue that can grow and undergo repair. The prenatal human skeleton is
initially cartilaginous but is later replaced by a bony skeleton. During adult life, bone is
continuously being broken down by osteoclasts and then rebuilt by osteoblasts that become
osteocytes in lacunae. Repair of a fracture requires four steps: (1) hematoma, (2)
fibrocartilaginous callus, (3) bony callus, and (4) remodeling.
Bones of the Skeleton
The skeleton supports and protects the body, allows flexible movement, produces blood cells,
and serves as a storehouse for mineral salts, mainly calcium phosphate. The axial skeleton lies in
the midline of the body and consists of the cranium, the hyoid bone, the vertebral column, and
the rib cage. The appendicular skeleton includes the bones of the pectoral girdle, arms, pelvic
girdle, and legs.
Articulations
There are three types of joints: fibrous joints, including the sutures of the skull, are
immovable; cartilaginous joints, including those between the ribs and sternum and the pubic
symphysis, are slightly movable; and synovial joints, including a membrane-lined (synovial
membrane) capsule, are freely movable.
Skeletal Muscles
Skeletal muscles have levels of organization. A whole muscle contains bundles of muscle
fibers; muscle fibers contain myofibrils; and myofibrils contain actin and myosin filaments.
Skeletal muscles are usually attached to the skeleton, where some are prime movers, some are
synergists, and others are antagonists.
Mechanism of Muscle Fiber Contraction
Nerve impulses travel down motor neurons and stimulate muscle fibers at neuromuscular
junctions. Calcium ions bind to troponin and cause the tropomyosin threads that wind around
actin filaments to shift their position, revealing myosin binding sites.
Full Muscle Contraction
In the laboratory, muscle contraction is described in terms of a muscle twitch, summation, and
tetanus. In the body, muscles exhibit tone, in which a continuous slight tension is maintained by
muscle fibers that take turns contracting.
Energy for Muscle Contraction
A muscle fiber has three ways to acquire ATP for muscle contraction. Exercise results in
muscle fiber growth, called hypertrophy.
Nervous Tissue
Nervous tissue consists of neurons, which are the cells that transmit nerve impulses, and
neuroglia, which support neurons. Sensory neurons take information from sensory receptors to
the CNS; interneurons occur in the CNS; and motor neurons take information from the CNS to
effectors (muscles or glands).
The Central Nervous System
The CNS consists of the spinal cord and brain, which are both protected by bone. The gray
matter of the spinal cord contains neuron cell bodies; the white matter contains myelinated axons
that occur in bundles called tracts.
The Limbic System and Higher Mental Functions
The limbic system connects portions of the cerebral cortex with the hypothalamus, the
thalamus, and basal nuclei. Language and speech are dependent upon Broca’s area (a motor
speech area) and Wernicke’s area (a sensory speech area).
The Peripheral Nervous System
The peripheral nervous system consists of nerves and ganglia. The cerebrum is always
involved in voluntary actions, but reflexes are automatic, and some do not require involvement
of the brain.
Drug Abuse
Though neurological drugs are quite numerous, each type has been found to either promote or
prevent the action of a particular neurotransmitter.
Homeostasis
Homeostasis is ultimately under the control of the nervous system. The hypothalamus and the
medulla oblongata have various centers that control the functioning of internal organs and the
internal environment.
