1. The Human Body:
An Orientation

2. Overview of Anatomy & Physiology
The science of the structure of living organisms.
ana = apart
tomy = to cut
Physiology
The science of the functioning of living organisms.
physio = nature
ology = the study of

3. Hierarchy of Structural Organization

4. Body Organ Systems

5. Functional Characteristics
Movement
All activities promoted by the muscular system.
Responsiveness
Sensing changes in the environment and responding to those changes.
Digestion
Breaking down of ingested foodstuffs to simple molecules that can be absorbed by body.
Metabolism
All chemical reactions that occur within body cells.

6. Functional Characteristics
Excretion
Process of removing wastes from the body.
Reproduction
Formation of offspring.
Growth
Increase in size.

7. Survival Needs Factors required to maintain life.
Nutrients used for energy and cell building.
Oxygen required for processing the nutrients.
Water provides the liquid environment for chemical reactions and fluid base for body secretions and excretions.
Body temperature must be maintained for chemical reactions to proceed at life sustaining rates.
Atmospheric pressure is a factor in breathing and the exchange of oxygen and carbon dioxide in the lungs.

8. Homeostasis Homeostasis
homeo = the same
stasis = standing still
A state of body equilibrium, or the maintenance of a stable internal environment of the body.
The body is said to be in homeostasis when its cells’ needs are adequately met and functional activities are occurring smoothly.

9. Characteristics of Control Mechanisms
Communication within the body is essential for homeostasis.
The nervous and endocrine (hormones) systems are responsible for this communication.
Afferent pathway
Efferent pathway

10. Feedback from Control Center
Negative Feedback
Is response that depresses the whole control mechanism.
The net effect is to decrease the original stimulus or reduce its effects.
Example: Body cells need continuous access to glucose. Blood sugar levels are maintained at a certain level. If levels of glucose are higher the control center sends message to store the excess glucose. Lowering the glucose levels.
Positive Feedback
Is response that enhances the control mechanism.
The net effect is to enhance the original stimulus or increase its effects.
Example: During labor, the body released “oxytocin” that stimulates the muscles that force the baby into the birth canal. This process causes contractions to come more frequently and more powerful, until baby is born.