Question

Negative feedback loops, although the most common, aren’t the only homeostasis mechanisms that exist. There are also positive feedback loops. While negative feedback loops work to counteract changes, positive feedback loops amplify the changes, moving a system away from its set point. This can sound dangerous, but in certain cases positive feedback loops are necessary. For example, when we bleed from a cut or other injuries, platelets release chemicals after detecting that a blood vessel has been damaged. These chemicals attract more platelets to the site of the injury, which then bind to the tissue and seal the cut by forming blood clots.

Which of the following is an example of a positive feedback loop?

A
Releasing insulin to counteract high blood sugar levels after consuming food

B
Shivering when external temperatures drop to increase body temperature

C
Releasing oxytocin during childbirth labor contractions, leading to more oxytocin being released

D
Sweating when it’s hot outside to cool the body down

Answer 1

The example of a positive feedback loop from the options provided is:

**C. Releasing oxytocin during childbirth labor contractions, leading to more oxytocin being released.**

In this case, the release of oxytocin causes more contractions, which in turn leads to the release of even more oxytocin, amplifying the process during childbirth. The other options describe negative feedback mechanisms that help to maintain homeostasis.