ANSWER THE ESSAYS AND THE QUESTIONS

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Skeletal System

Overview of Bones

Anatomy of Skeletal System

  • Divisions
  • Axial
  • Appendicular
  • Girdles
  • Limbs
  • Joints
  • Flexibility
  • Allow movement
  • Cartilage
  • Ligaments
  • Fibrous cords
  • Bind bones together at joints

Functions of Bones

  • Support
  • Protection
  • Movement
  • Storage
  • Blood Cell Formation

Support

  • Form internal framework
  • Support and anchor soft organs
  • Legs support body trunk
  • Rib cage supports thoracic wall

Protection

  • Protect soft body organs
  • Skull
  • Vertebrae
  • Rib Cage

Movement

  • Tendons connect skeletal muscles to bones

Storage

  • Fat in internal cavities of bones
  • Storehouse minerals
  • Calcium
  • Phosphorous

Blood Cell Formation

  • Hematopoeisis
  • Occurs within marrow cavities of some bones

Classification of Bones

  • 206 bones in adult skeleton
  • 2 Types Osseous Tissue
  • Shape

Osseous Tissue

  • Compact
  • Spongy

Compact Bone

  • Dense
  • Looks smooth

Spongy Bone

  • Needlike pieces of bone
  • Trabeculae
  • Bars
  • Lot of open space

Bone Shape

Long Bones

  • Longer than wide
  • Shaft with heads at both ends
  • Mostly compact bone
  • All bones of limbs
  • Except ankle and wrist bones

Short Bones

  • Cube-shaped
  • Mostly spongy bone
  • Wrist and ankle
  • Sesamoid
  • Special type
  • Form within tendons
  • Patella

Flat Bones

  • Thin, flattened, usually curved
  • Layer spongy bone between two wafferlike layers compact bone
  • Skull, ribs, sternum

Irregular Bones

  • Do not fit into another category
  • Vertebrae, hip bones

Structure of Long Bone

  • Diaphysis
  • Shaft
  • Bone length
  • Compact bone

Compact bone

Structure of Long Bone

  • Periosteum
  • Fibrous membrane
  • Covers diaphysis

Structure of Long Bone

  • Sharpey’s Fibers
  • Secure periosteum to underlying bone

Structure of Long Bone

  • Epiphysis
  • Ends of long bone
  • Thin layer compact bone enclosing spongy bone

Spongy bone

Structure of Long Bone

  • Articular Cartilage
  • Covers external surface of epiphysis
  • Hyaline cartilage
  • Smooth, slippery surface
  • Decreases friction at joint surfaces

Structure of Long Bone

  • Epiphyseal Line
  • Remnant of epiphyseal plate
  • End of puberty
  • Epiphyseal Plate
  • Flat plate of hyaline cartilage
  • Young, growing bone
  • Cause lengthwise growth of long bone

Structure of Long Bone

  • Adult shaft cavity
  • Yellow Marrow
  • Storage for adipose tissue
  • Aka medullary cavity
  • Infant shaft cavity
  • Red marrow
  • Forms rbc
  • Red marrow in adults confined to spongy bone of flat bones and epiphysis of long bones

Bone Markings

  • Bones not smooth surfaces
  • Bumps, holes, ridges
  • Bone markings
  • Where muscles, tendons, and ligaments attached
  • Where blood vessels and nerves pass

Bone Marking Categories

  • Projections or Processes
  • Grow out from bones
  • Sites muscle attachment
  • Form joints
  • Depressions or cavities
  • Indentations
  • Openings
  • Passageway for nerves & blood vessels

Microscopic Anatomy

  • Spongy bone
  • Spiky open appearance
  • Compact bone
  • Dense appearance

Microscopic Structure of Compact Bone

  • Osteocytes
  • Mature bone cells
  • In lacunae

Microscopic Structure of Compact Bone

  • Lacunae
  • Cavities within matrix
  • Arranged in concentric circles

Microscopic Structure of Compact Bone

  • Lamellae
  • Concentric circles

Microscopic Structure of Compact Bone

  • Central (Haversian) Canal
  • Carries blood vessels and nerves to bone

Microscopic Structure of Compact Bone

  • Osteon (Haversian System)
  • Central canal and matrix rings

Microscopic Structure of Compact Bone

  • Canaliculi
  • Tiny canals
  • Radiate outward from central canal
  • Supply lacunae
  • Connect bone cells to nutrient supply

Microscopic Structure of Compact Bone

  • Perforating (Volkmann’s) Canals
  • Communication pathway from outside bone to interior

Bone Formation

  • Skeletal system made of strong, supportive tissues
  • Cartilage
  • Bone
  • Embryos
  • Primarily hyaline cartilage
  • Child
  • Most cartilage replaced by bone
  • Cartilage remains in nose, ribs, joints

Bone Formation

  • Hyaline cartilage model
  • Except flat bones – fibrous membranes
  • Ossification
  • Bone formation
  • Osteoblasts
  • 2 phases
  • Hyaline cartilage covered w/ bone matrix
  • Hyaline cartilage digested, opens up medullary cavity

Development of Bone

  • Fetus
  • Cartilage bones enclosed by bony bones
  • Birth
  • Hyaline cartilage converted to bone
  • Except
  • articular cartilage (bone ends) reduces friction at joint surfaces
  • epiphyseal plates for growth long bones

Appositional Growth

  • Bone widening
  • Osteoblasts in periosteum
  • Add bone tissue to external diaphysis
  • Osteoclasts in endosteum
  • Remove bone from inner diaphysis

Regulation of Bone Growth

  • Hormones
  • GH
  • Sex hormones
  • Puberty ends
  • Epiphyseal plate converted to bone
  • Bone still dynamic and active tissues

Bone Remodeling

  • Retain normal proportions and strength
  • Long bone growth
  • Body increases size/weight
  • Bones thicker and form large projections to increase strength
  • Response to
  • Calcium levels in blood
  • Pull gravity and muscles

Bone Remodeling

  • Stress
  • Osteoblasts lay down new matrix
  • Become trapped
  • Become osteocytes
  • Bedridden/Physically Inactive People
  • Bones loose mass
  • Atrophy

Bone Remodeling

  • PTH
  • Break down of bones
  • Stimulates osteoclasts
  • Need more calcium ions in blood
  • Calcitonin
  • Build up of bones
  • Stimulates osteoblasts
  • Excess calcium in blood
  • Stress
  • Where bone matrix broken down or formed
  • Skeleton stays strong

Rickets Disease

  • Bones fail to calcify
  • Bones soften
  • Bowing of legs
  • Lack of calcium in diet
  • Lack vitamin D
  • Needed to absorb calcium

Bone Fractures

  • Breaks
  • Closed (simple)
  • Bone breaks cleanly
  • Does not penetrate skin
  • Open (compound)
  • Broken bone ends penetrate skin

Types of Fractures

  • Comminuted
  • Compression
  • Depressed
  • Impacted
  • Spiral
  • Greenstick

Comminuted Fracture

  • Bone breaks into many fragments
  • Common in aged
  • Bones brittle

Compression Fracture

  • Bone crushed
  • Common in porous bones

Depressed Fracture

  • Broken bone portion pressed inward
  • Skull fracture

Impacted Fracture

  • Broken bone ends forced into each other
  • Break a fall w/ outstretched arms

Spiral Fracture

  • Ragged break occurs
  • Twisting forces
  • Sports fracture

Greenstick Fracture

  • Bone breaks incompletely
  • Green twig breaks
  • Common in children
  • Bones more flexible than adults

Treating Fractures

  • Reduction
  • Realignment of broken bone ends
  • Closed reduction
  • Bone ends coaxed back into normal position
  • Open reductions
  • Surgery performed
  • Bone ends secured together w/ pins
  • Immobilized by cast allow healing
  • 6-8 weeks

Bone Fracture Repair

  • Hematoma
  • Break splinted by fibrocartilage callus
  • Bony callus forms
  • Bony callus remodeled

Hematoma

  • Blood vessels ruptured
  • Blood filled swelling
  • Bone cells die

Fibrocartilage Callus

  • Splints break
  • Tissue repair
  • Growth new capillaries
  • Phagocytes get dispose dead tissue
  • Connective tissue cells repair tissue
  • Fibrocartilage callus
  • Cartilage, bony matrix w/ collagen fibers
  • Closes gap

Bony Callus

  • Osteoblasts and osteoclasts migrate into area
  • Multiply
  • Fibrocartilage replaced by callus
  • Spongy bone