Negative Feedback Loops

Negative feedback loops involve the process by which particular factors change, but ultimately reach homeostasis (or constant levels that are considered normal). Negative feedback loops happen all throughout nature, in plants and in animals. In humans we often see Negative feedback loops in relation to blood sugar or body temperature, or other similar physical factors.

In class we used the example of blood sugar to demonstrate how negative feedback loops work. Dr. Rood tested his blood sugar at the beginning of class, and then consumed a soda and a candy bar before testing his blood sugar again. The graph below shows how his blood sugar levels changed.

There was a clear increase in blood sugar in the minutes following Dr. Rood's consumption of the junk food. However, his body was able to recognize the spike and prevent the levels from becoming dangerously high. A negative feedback loop slowly occurred, in which his body brought the levels back down to normal. His body had reached homeostasis, and he was in no danger of becoming sick due to the intake of sugar. However, if Dr. Rood had been diabetic, then his body would not have been able to properly control the blood sugar level and reach homeostasis, which would have put him at risk of illness.