1. Necessary Life Functions
EQ: What are the necessary life functions of the human body?
SAP1 c. Explain the role of homeostasis and its mechanisms
as these relate to the body as a whole
and predict the consequences of the failure
to maintain homeostasis.
SAP1 d. Relate cellular metabolism and transport to homeostasis
and cellular reproduction.

2. Necessary Life Functions
Movement
Locomotion
Movement of substances
Responsiveness
Ability to sense changes and react
Digestion
Break-down and delivery of nutrients

3. Necessary Life Functions
Metabolism – chemical reactions within the body
Production of energy
Making body structures
Excretion
Elimination of waste from metabolic reactions

4. Necessary Life Functions
Reproduction
Production of future generation
Growth and development
Increasing of cell size and number

5. Survival Needs Nutrients Chemicals for energy and cell building
Includes carbohydrates, proteins, lipids, vitamins, and minerals
Oxygen
Required for chemical reactions

6. Survival Needs Water 60–80% of body weight
Provides for metabolic reaction
Stable body temperature
Atmospheric pressure must be appropriate

7. Homeostasis
Maintenance of a stable internal environment = a dynamic state of equilibrium
Homeostasis must be maintained for normal body functioning and to sustain life
Homeostatic imbalance – a disturbance in homeostasis resulting in disease

8. Overview of Homeostasis
Figure 1.4

9. Maintaining Homeostasis
The body communicates through neural and hormonal control systems
Receptor
Responds to changes in the environment (stimuli)
Sends information to control center

10. Maintaining Homeostasis
Control center
Determines set point
Analyzes information
Determines appropriate response
Effector
Provides a means for response to the stimulus

11. Feedback Mechanisms Negative feedback
Includes most homeostatic control mechanisms
Shuts off the original stimulus, or reduces its intensity
Works like a household thermostat

12. Feedback Mechanisms Positive feedback
Increases the original stimulus to push the variable farther
In the body this only occurs in blood clotting and birth of a baby

13. Summarizer
Describe a scenario in which the body’s homeostasis is interrupted and describe how the body might work to bring itself back to homeostasis