1. September 13, 2013
Objective: To describe homeostasis and use medical terminology effectively
Journal: What is homeostasis?

2. Homeostasis

3. Video
portal.com/academy/lesson/homeostasis- and-temperature-regulation-in-humans.html

4. Homeostasis
Physiological mechanisms that work to maintain a constant internal environment
Examples?

5. Components of Homeostatic Mechanisms
Receptor – detects stimuli and sends signal on an afferent pathway to the control center.
Control Center – interprets signal and decides how to act.
Effector – information flows from the control center along the efferent pathway to the effector.

6. How do homeostatic mechanisms work?
If the body detects that its normal set-point is either to high or to low it will respond.
Control
Center
Efferent Pathway
Afferent Pathway
Receptor
(Start)
Effector

7. Example When your body gets to hot, what happens?
Send signal to control center in the brain
Brain signals a response
Sweat is released and blood vessels get bigger

8. Positive Feedback Loops
Loop continues in the same direction and increases magnitude of change to the body

9. Negative Feedback Loops
Loop moves in the opposite direction of a stimulus

10. Determine if the scenario represents a positive or negative feedback homeostatic system:
A car starts rolling out of a driveway w/o a driver. A person decides to respond by pushing the car in the direction that makes it leave the driveway faster.
Your blood calcium level is low so your body begins to break down bone tissue so that calcium is released into the blood.
A neuron is stimulated and sodium goes rushing into the cell. The more it is stimulated the more sodium goes rushing in, thus enhancing the stimulus.

11. Metabolism
In order to maintain homeostasis many chemical reactions have to take place in your body. These chemical reactions are collectively called your metabolism

12. Two Types of Metabolic Pathways:
1. Anabolism – the process by which simpler compounds are built up and used for growth, repair and reproduction.
Examples - cellular respiration to ATP
2. Catabolism – the process by which complex substances are broken down into simpler substances.
Examples – hydrolysis of fats or glycogen.