1. Rapid change in one direction Does not maintain homeostasis
Positive Feedback
Rapid change in one direction
Does not maintain homeostasis

2. Helpful examples of positive feedback
Birth
Head of baby pushing on cervix stimulates oxytocin, which contracts the uterus, which pushes the head against the cervix, which stimulates oxytocin, which causes the uterus to contract, which pushes the head against the cervix
Protein digestion
Blood clotting

3. Harmful example of positive feedback
Fever
High body temp causes proteins to denature (lose shape) which causes body temp to rise,

4. Keeps a variable close to a set point Maintains homeostasis
Negative Feedback
Keeps a variable close to a set point
Maintains homeostasis

5. Example of negative feedback
Body temperature
Temp above 98.6F causes hypothalamus (in brain) sends signal for blood vessels to dilate and sweat to secrete
Temp lowers to 98.6F which stops the signal
Temp below 98.6F causes hypothalamus to send signal for muscles to shiver, blood vessels to constrict
Temp raises to 98.6F which stops the signal

6. Example of negative feedback
Blood sugar
Blood glucose level rises as meal is digested and nutrients pass through small intestine into blood
Pancreas secretes insulin which moves glucose out of blood into cells
Blood glucose level drops as glucose is used to make ATP (energy)
Pancreas secretes glucagon which moves glucose out of cells and into blood

7. Positive and Negative Feedback Loops (Bozeman Science)

8. Homeostatic Loops (Bozeman Science)

9. Elements of a Feedback Loop (Bozeman Science)