IGCSE science: Negative Feedback

Question

Explain how negative feedback and a set point are involved in the control of blood glucose concentration.

Answer 1

A feedback loop links a response back to an initial stimulus. In a negative feedback loop the response reduces the initial stimulus.

In humans the set point of glucose is 70-110 mg/100 mL. The body uses the opposing hormones insulin and glucagon to maintain this blood glucose level. When glucose levels rise, it triggers the release of insulin from pancreas that helps cells absorb the glucose and store it. When the glucose levels drop below a set point glucagon promotes the release of glycogen from stored supplies like liver glycogen to bring the glucose levels up to the set point.

Answer 2

Negative feedback involves insulin and glucagon help to keep blood sugar levels within a narrow concentration range. if the glucose levels get too high insulin is released in the blood stream. If the glucose levels get too low pancreas releases the hormone Glucagon