1. Activity 2: Feedback Mechanisms

2. Maintaining homeostasis
The endocrine system works with the nervous system to keep the body in a stable condition.
The nervous system sends signals to glands in the endocrine system to either promote or inhibit the secretion of hormones.

3. The increased or decreased release of hormones helps regulate:
Heart rate
Cellular metabolism
Digestion
Sugar levels
Sexual Development
This interaction between the nervous system and endocrine system to maintain a stable internal environment results in feedback mechanisms.

4. There are two types of feedback:
Negative feedback
Positive feedback
We will be focusing more on negative feedback mechanisms

5. Negative Feedback
Negative feedback mechanisms are triggered when a change occurs which disrupts normal functions and conditions of the body. These mechanisms try to bring the body back to its normal state by reversing the change that occurred.
Example: When it is cold outside, our bodies undergo a shivering process to heat up our bodies

7. Too little water in the blood

8. Too much water in the blood

9. Discussion Questions:
1. Does the nervous system or the endocrine system play the larger role in regulating organ function in the human body? Or do both play an equal part in this regulation? Based your answer on the diagrams in the powerpoint.
2. You are a doctor and have just prescribed your patient a new drug. Experiments conducted on the effectiveness of the drug have found that many patients suffer from dehydration. Using your knowledge of feedback mechanisms, provide one explanation for how your patient could become dehydrated.
3. Make a prediction: What could be a possible solution to re- hydrate your patient?

10. Finish Early?
In Unit 2, the big connection was made between the function of a cell and that of a city.
Using the cell to city analogy, give an example of a structure in a city that would be similar to:
- the endocrine system
- the nervous system
- hormones