ANSWER THE ESSAYS AND THE QUESTIONS

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Bio201 Human Anatomy & Physiology I

Lecture 1 (Chapter 1)

Overview of Anatomy and Physiology

Anatomy
Study of structure
Subdivisions:
Gross or macroscopic (e.g., regional, systemic, and surface anatomy)
Microscopic (e.g., cytology and histology)
Developmental (e.g., embryology)

Overview of Anatomy and Physiology

To study anatomy
Mastery of anatomical terminology
Observation
Manipulation
Palpation
Auscultation

Overview of Anatomy and Physiology

Physiology
Study of the function of the body
Subdivisions based on organ systems
(e.g., renal or cardiovascular physiology)
Often focuses on cellular and molecular level
Body's abilities depend on chemical reactions in individual cells

Overview of Anatomy and Physiology

To study physiology
Ability to focus at many levels (from systemic to cellular and molecular)
Study of basic physical principles (e.g., electrical currents, pressure, and movement)
Study of basic chemical principles

Principle of Complementarity

Anatomy and physiology are inseparable
Function always reflects structure
What a structure can do depends on its specific form

Levels of Structural Organization

Chemical
Atoms and molecules (chapter 2); and organelles (chapter 3)
Cellular
Cells (chapter 3)
Tissue
Groups of similar cells (chapter 4)
Organ
Contains two or more types of tissues
Organ System
Organs that work closely together
Organismal
All organ systems

Figure 1.1 Levels of structural organization.

Slide 1

Atoms

Molecule

Organelle

Smooth muscle cell

Chemical level

Atoms combine to

form molecules.

Cellular level

Cells are made up

of molecules.

Smooth muscle tissue

Cardiovascular

system

Heart

Blood

vessels

Tissue level

Tissues consist of

similar types of cells.

Blood vessel (organ)

Smooth muscle tissue

Connective tissue

Epithelial

tissue

Organ level

Organs are made up of different types

of tissues.

Organismal level

The human organism is made

up of many organ systems.

Organ system level

Organ systems consist of different

organs that work together closely.

Figure 1.1 Levels of structural organization.

Slide 2

Atoms

Molecule

Chemical level

Atoms combine to

form molecules.

Figure 1.1 Levels of structural organization.

Slide 3

Atoms

Molecule

Organelle

Smooth muscle cell

Chemical level

Atoms combine to

form molecules.

Cellular level

Cells are made up

of molecules.

Figure 1.1 Levels of structural organization.

Slide 4

Atoms

Molecule

Organelle

Smooth muscle cell

Chemical level

Atoms combine to

form molecules.

Cellular level

Cells are made up

of molecules.

Tissue level

Tissues consist of

similar types of cells.

Smooth muscle tissue

Figure 1.1 Levels of structural organization.

Slide 5

Atoms

Molecule

Organelle

Smooth muscle cell

Chemical level

Atoms combine to

form molecules.

Cellular level

Cells are made up

of molecules.

Smooth muscle tissue

Tissue level

Tissues consist of

similar types of cells.

Blood vessel (organ)

Smooth muscle tissue

Connective tissue

Epithelial

tissue

Organ level

Organs are made up of different types

of tissues.

Figure 1.1 Levels of structural organization.

Slide 6

Atoms

Molecule

Organelle

Smooth muscle cell

Chemical level

Atoms combine to

form molecules.

Cellular level

Cells are made up

of molecules.

Smooth muscle tissue

Cardiovascular

system

Heart

Blood

vessels

Tissue level

Tissues consist of

similar types of cells.

Blood vessel (organ)

Smooth muscle tissue

Connective tissue

Organ level

Organs are made up of different types

of tissues.

Organ system level

Organ systems consist of different

organs that work together closely.

Epithelial

tissue

Figure 1.1 Levels of structural organization.

Slide 7

Atoms

Molecule

Organelle

Smooth muscle cell

Chemical level

Atoms combine to

form molecules.

Cellular level

Cells are made up

of molecules.

Smooth muscle tissue

Cardiovascular

system

Heart

Blood

vessels

Tissue level

Tissues consist of

similar types of cells.

Blood vessel (organ)

Smooth muscle tissue

Connective tissue

Organ level

Organs are made up of different types

of tissues.

Organismal level

The human organism is made

up of many organ systems.

Organ system level

Organ systems consist of different

organs that work together closely.

Epithelial

tissue

Necessary Life Functions

Maintaining boundaries
Movement
Responsiveness
Digestion
Metabolism
Dispose of wastes
Reproduction
Growth

Necessary Life Functions

Maintaining boundaries between internal and external environments
Plasma membranes
Skin
Movement (contractility)
Of body parts (skeletal muscle)
Of substances (cardiac and smooth muscle)

Necessary Life Functions

Responsiveness
Ability to sense and respond to stimuli
Withdrawal reflex
Control of breathing rate
Digestion
Breakdown of ingested foodstuffs
Absorption of simple molecules into blood

Necessary Life Functions

Metabolism
All chemical reactions that occur in body cells
Catabolism and anabolism
Excretion
Removal of wastes from metabolism and digestion
Urea, carbon dioxide, feces

Necessary Life Functions

Reproduction
Cellular division for growth or repair
Production of offspring
Growth
Increase in size of a body part or of organism

Interdependence of Body Cells

Humans are multicellular
To function, must keep individual cells alive
All cells depend on organ systems to meet their survival needs
All body functions spread among different organ systems
Organ systems cooperate to maintain life
Note major organs and functions of the 11 organ systems (fig. 1.3)

Figure 1.2 Examples of interrelationships among body organ systems.

Digestive system

Takes in nutrients, breaks them
down, and eliminates unabsorbed
matter (feces)

Food

CO2

Respiratory system

Takes in oxygen and
eliminates carbon dioxide

Cardiovascular system

Via the blood, distributes oxygen
and nutrients to all body cells and
delivers wastes and carbon
dioxide to disposal organs

Blood

CO2

Heart

Nutrients

Interstitial fluid

Integumentary system Protects the body as a whole from the external environment

Nutrients and wastes pass between blood and cells
via the interstitial fluid

Feces

Urine

Urinary system Eliminates
nitrogenous

wastes and

excess ions

Figure 1.3a The body’s organ systems and their major functions.

Hair

Skin

Nails

Integumentary System

Forms the external body covering,

and protects deeper tissues from injury.

Synthesizes vitamin D, and houses

cutaneous (pain, pressure, etc.)

receptors and sweat and oil glands.

Figure 1.3b The body’s organ systems and their major functions.

Joint

Bones

Skeletal System

Protects and supports body organs,
and provides a framework the muscles
use to cause movement. Blood cells
are formed within bones. Bones store minerals.

Figure 1.3c The body’s organ systems and their major functions.

Skeletal

muscles

(c)

Muscular System

Allows manipulation of the environment,

locomotion, and facial expression.

Maintains posture, and produces heat.

Figure 1.3d The body’s organ systems and their major functions.

Brain

Nerves

Spinal

cord

Nervous System

As the fast-acting control system of

the body, it responds to internal and

external changes by activating

appropriate muscles and glands.

Figure 1.3e The body’s organ systems and their major functions.

Endocrine System

Glands secrete hormones that

regulate processes such as growth,

reproduction, and nutrient use

(metabolism) by body cells.

Pineal gland

Pituitary

gland

Testis

Thyroid

gland

Thymus

Adrenal

gland

Pancreas

Ovary

Figure 1.3f The body’s organ systems and their major functions.

Cardiovascular System

Blood vessels transport blood,

which carries oxygen, carbon dioxide,

nutrients, wastes, etc. The heart

pumps blood.

Heart

Blood

vessels

Figure 1.3g The body’s organ systems and their major functions.

Lymphatic System/Immunity

Picks up fluid leaked from blood vessels

and returns it to blood. Disposes

of debris in the lymphatic stream.

Houses white blood cells (lymphocytes)

involved in immunity. The immune

response mounts the attack against

foreign substances within the body.

Lymph nodes

Spleen

Thoracic

duct

Lymphatic

vessels

Thymus

Red bone

marrow

Figure 1.3h The body’s organ systems and their major functions.

Respiratory System

Keeps blood constantly supplied with

oxygen and removes carbon dioxide.

The gaseous exchanges occur through

the walls of the air sacs of the lungs.

Lung

Trachea

Larynx

Pharynx

Nasal

cavity

Bronchus

Figure 1.3i The body’s organ systems and their major functions.

Oral cavity

Esophagus

Liver

Stomach

Small

Intestine

Large

Intestine

Rectum

Anus

Digestive System

Breaks down food into absorbable units

that enter the blood for distribution to

body cells. Indigestible foodstuffs are

eliminated as feces.

Kidney

Ureter

Urinary

bladder

Urethra

Urinary System

Eliminates nitrogenous wastes from the

body. Regulates water, electrolyte and

acid-base balance of the blood.

Figure 1.3j The body’s organ systems and their major functions.

Prostate

gland

Penis

Testis

Scrotum

Ductus

deferens

Male Reproductive System

Overall function is production of offspring. Testes

produce sperm and male sex hormone, and male

ducts and glands aid in delivery of sperm to the

female reproductive tract. Ovaries produce eggs

and female sex hormones. The remaining female

structures serve as sites for fertilization and

development of the fetus. Mammary glands of

female breasts produce milk to nourish the newborn.

Uterus

Vagina

Uterine

tube

Ovary

Mammary

glands (in

breasts)

Female Reproductive System

Overall function is production of offspring. Testes

produce sperm and male sex hormone, and male

ducts and glands aid in delivery of sperm to the

female reproductive tract. Ovaries produce eggs

and female sex hormones. The remaining female

structures serve as sites for fertilization and

development of the fetus. Mammary glands of female

breasts produce milk to nourish the newborn.

Figure 1.3k–l The body’s organ systems and their major functions.

Survival Needs

Appropriate amounts necessary for life
Too little or too much harmful
Nutrients
Oxygen
Water
Normal body temperature
Appropriate atmospheric pressure

Survival Needs

Nutrients
Chemicals for energy and cell building
Carbohydrates, fats, proteins, minerals, vitamins
Oxygen
Essential for energy release (ATP production)

Survival Needs

Water
Most abundant chemical in body
Environment of chemical reactions
Fluid base for secretions and excretions
Normal body temperature
37° C
Affects rate of chemical reactions
Appropriate atmospheric pressure
For adequate breathing and gas exchange in lungs

Homeostasis

Homeostasis
Maintenance of relatively stable internal conditions despite continuous changes in environment
A dynamic state of equilibrium
Maintained by contributions of all organ systems

Homeostatic Control Mechanisms

Involve continuous monitoring and regulation of all factors that can change (variables)
Communication necessary for monitoring and regulation
Functions of nervous and endocrine systems
Nervous and endocrine systems accomplish communication via nerve impulses and hormones

Components of a Control Mechanism

Receptor (sensor)
Monitors environment
Responds to stimuli (something that causes changes in controlled variables)
Control center
Determines set point at which variable is maintained
Receives input from receptor
Determines appropriate response
Effector
Receives output from control center
Provides the means to respond
Response either reduces (negative feedback) or enhances stimulus (positive feedback)

Figure 1.4 Interactions among the elements of a homeostatic control system maintain
stable internal conditions.

Slide 1

Output: Information sent

along efferent pathway to

effector.

Input: Information

sent along afferent

pathway to control

center.

Receptor

detects

change.

Stimulus

produces

change in

variable.

Response

of effector

feeds back to

reduce the

effect of

stimulus and

returns

variable

to homeostatic

level.

Control

Center

Afferent

pathway

Efferent

pathway

Receptor

Effector

BALANCE

IMBALANCE

Figure 1.4 Interactions among the elements of a homeostatic control system maintain
stable internal conditions.

Slide 2

Stimulus

produces

change in

variable.

BALANCE

IMBALANCE

Figure 1.4 Interactions among the elements of a homeostatic control system maintain
stable internal conditions.

Slide 3

Stimulus

produces

change in

variable.

Receptor

detects

change.

BALANCE

IMBALANCE

Receptor

Figure 1.4 Interactions among the elements of a homeostatic control system maintain
stable internal conditions.

Slide 4

Afferent

pathway

Stimulus

produces

change in

variable.

Receptor

detects

change.

Input: Information

sent along afferent

pathway to control

center.

BALANCE

IMBALANCE

Receptor

Control

Center

Figure 1.4 Interactions among the elements of a homeostatic control system maintain
stable internal conditions.

Slide 5

Afferent

pathway

Efferent

pathway

Stimulus

produces

change in

variable.

Receptor

detects

change.

Input: Information

sent along afferent

pathway to control

center.

BALANCE

IMBALANCE

Receptor

Control

Center

Effector

Output: Information sent

along efferent pathway to

effector.

Figure 1.4 Interactions among the elements of a homeostatic control system maintain
stable internal conditions.

Slide 6

Afferent

pathway

Efferent

pathway

Stimulus

produces

change in

variable.

Receptor

detects

change.

Input: Information

sent along afferent

pathway to control

center.

BALANCE

IMBALANCE

Receptor

Control

Center

Effector

Output: Information sent

along efferent pathway to

effector.

Response

of effector

feeds back to

reduce the

effect of

stimulus and

returns

variable

to homeostatic

level.

Negative Feedback

Most feedback mechanisms in body
Response reduces or shuts off original stimulus
Variable changes in opposite direction of initial change
Examples
Regulation of body temperature (a nervous system mechanism)
Regulation of blood glucose by insulin (an endocrine system mechanism)

Figure 1.5 Body temperature is regulated by a negative feedback mechanism.

Control Center

(thermoregulatory

center in brain)

Afferent

pathway

Efferent

pathway

Receptors

Temperature-sensitive

cells in skin and brain)

Effectors

Sweet glands

Sweat glands activated

Response

Evaporation of sweat

Body temperature falls;

stimulus ends

Body temperature

rises

Stimulus: Heat

Response

Body temperature rises;

stimulus ends

Effectors

Skeletal muscles

Efferent

pathway

Shivering begins

BALANCE

IMBALANCE

Afferent

pathway

Control Center

(thermoregulatory

center in brain)

Receptors

Temperature-sensitive

cells in skin and brain

Stimulus: Cold

Body temperature

falls

Negative Feedback:
Regulation of Blood Glucose by Insulin

Receptors sense increased blood glucose (blood sugar)
Pancreas (control center) secretes insulin into the blood
Insulin causes body cells (effectors) to absorb more glucose, which decreases blood glucose levels

Positive Feedback

Response enhances or exaggerates original stimulus
May exhibit a cascade or amplifying effect
Usually controls infrequent events that do not require continuous adjustment
Enhancement of labor contractions by oxytocin (chapter 28)
Platelet plug formation and blood clotting

Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug.

Slide 1

Released

chemicals

attract more

platelets.

Positive

feedback

loop

Platelets

adhere to site and

release chemicals.

Feedback cycle ends

when plug is formed.

Platelet plug

is fully formed.

Break or tear

occurs in blood

vessel wall.

Positive feedback

cycle is initiated.

Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug.

Slide 2

Positive feedback

cycle is initiated.

Break or tear

occurs in blood

vessel wall.

Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug.

Slide 3

Positive feedback

cycle is initiated.

Break or tear

occurs in blood

vessel wall.

Platelets

adhere to site and

release chemicals.

Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug.

Slide 4

Positive

feedback

loop

Positive feedback

cycle is initiated.

Break or tear

occurs in blood

vessel wall.

Platelets

adhere to site and

release chemicals.

Released

chemicals

attract more

platelets.

Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug.

Slide 5

Positive

feedback

loop

Feedback cycle ends

when plug is formed.

Positive feedback

cycle is initiated.

Break or tear

occurs in blood

vessel wall.

Platelets

adhere to site and

release chemicals.

Platelet plug

is fully formed.

Released

chemicals

attract more

platelets.

Homeostatic Imbalance

Disturbance of homeostasis
Increases risk of disease
Contributes to changes associated with aging
Control systems less efficient
If negative feedback mechanisms overwhelmed
Destructive positive feedback mechanisms may take over (e.g., heart failure)