What is an example of a negative feedback system in homeostasis?

An example of a negative feedback system in homeostasis is the regulation of blood glucose levels. This process exemplifies how the body maintains internal stability through feedback mechanisms.

When blood glucose levels rise after eating, the pancreas detects this increase and responds by releasing insulin, a hormone that facilitates the uptake of glucose by cells, lowering blood glucose levels back to a normal range. Conversely, when blood glucose levels drop too low, the pancreas secretes glucagon, another hormone that promotes the release of glucose into the bloodstream from the liver.

This system is self-regulating: insulin lowers glucose levels when they are too high, and glucagon raises them when they are too low. Thus, it demonstrates classic negative feedback where the response to a stimulus counteracts the initial change, maintaining homeostasis.

The other options describe various processes but do not exemplify negative feedback. Increased heart rate during exercise is a positive feedback mechanism since it accelerates heart rate to meet the body's increased demand for oxygen and nutrients. Changes in respiratory rate during sleep may be regulatory, but they don't operate based on feedback correction like blood glucose regulation. Lastly, body temperature rising in hot weather signifies a disruption that can trigger responses like sweating, but this too is not a homeostatic feedback loop