1. Homeostasis Presentation

2. What must we do to maintain life?
1. Maintain Boundaries
Skin covers us and protects us from the external environments that we live in
2. Movement
Skeletal muscle allows us to move and if necessary protect ourselves
3. Responsiveness –
Ability to detect changes and make proper adjustments
4. Digestion
Breakdown foods to get nutrients for growth, development, and homeostasis

3. Maintain Continued 5. Metabolism
Ability to take nutrients and use them to build, and energize the body
6. Excretion
Removal of wastes
7. Reproduction
Pass on good genes to future generations
8. Growth
Increase in size

4. What things do we need to survive?
1. Nutrients
2. Water
3. Oxygen
4. Stable temperature
5. Environment that is at 1 ATM of pressure

5. Homeostatic Control Mechanisms
Consist of 3 key parts
Receptor
Stimulated by a change in the environment
Carries impulses to the CNS via afferent pathways
2. Control Center
Needs to determine what to do when it gets the impulse
3. Effector
Responds to the original stimulus
Receives direction from the control center
Uses an efferent pathway

7. Negative Feedback
Most homeostatic control mechanisms fall under this category
Effect of the response is to shut off the stimulus, or to reduce its intensity
Insulin control of blood sugar is a good example
After a meal blood sugar rises, and so insulin is released by the pancreas
This allows us to move glucose into cells
As the level of glucose drops, so does the level of insulin
This repeats each time we eat

9. Positive Feedback Rare in the body
Here the response intensifies the original stimulus
Usually these responses lead to a major event for the person
Examples are blood clotting, and childbirth