Negative Feedback Loops

• causes a decrease in function

• the feedback tends to stabilize the system

• occurs in response to some kind of stimulus

• can be referred to as homeostasis, as in biology

Example of Negative Feedback

Control of blood sugar (glucose) by insulin is a good example of a negative feedback mechanism. When blood sugar rises, receptors in the body sense a change. In turn, the control center (pancreas) secretes insulin into the blood effectively lowering blood sugar levels.

Positive Feedback

• occurs in nature when the product of a reaction leads to an increase in that reaction

• in homeostasis, a positive feedback loop moves a system further away from the target of equilibrium

• Example, ripening of fruit or childbirth