1. Endocrine System
Function – controls body activities through chemical regulation.
Hormones – chemicals secreted by glands that travel to other parts of the body.
- hormones affect growth, reproduction, blood sugar levels.

2. Glands – secrete hormones directly into blood.
Ex: Adrenal glands, pancreas, parathyroid

3. Receptor Molecules – found on cell surfaces, bind to hormones.

4. Feedback Mechanisms
1. Positive Feedback – a change in the body leads to an even greater change. Ex: Oxytocin – labor contractions
2. Negative Feedback – a change leads to a return to homeostasis.
Ex: glucose-insulin

5. Glucose/Insulin negative feedback

6. Positive Feedback Loop

7. Dynamic Equilibrium - constant small corrections that keep internal environment stable.
Fight or Flight – when a stimulus causes a reaction that leads to increased heart rate, dilated pupils, etc that would help to fight or escape.