Question

3. Some tiny particles are breathed in through the nostrils. They lodge themselves in the nasal mucosa at the top of the nose, irritating the membrane there. Irritation of the nasal mucosa causes the release of histamine from some nearby connective tissue cells. Histamine causes fluid to gather near the neurons in the mucous membrane of the nose. This irritates the neurons in the mucosa, causing histamine release, leading to irritation of the mucosa. When enough fluid has built up, the irritation in the mucosal neurons causes activation of the trigeminal nerve leading to a sneeze.

A. Is this an example of positive feedback or negative feedback?

B. Use your knowledge of the characteristics of positive and negative feedback to explain your reasoning. Do not just repeat what is stated in the question – use the facts provided in the question and your knowledge of feedback mechanisms to explain your answer.

4. When the amount of glucose in the blood is high the pancreas secretes insulin. Insulin signals the cells of the body to take up available glucose and use it or store. The glucose is then allowed to enter the cells of the body and is no longer in the bloodstream. The pancreas notices the drop in blood glucose and stops secreting Insulin.

A. Is this an example of positive feedback or negative feedback?

B. Use your knowledge of the characteristics of positive and negative feedback to explain your reasoning. Do not just repeat what is stated in the question – use the facts provided in the question and your knowledge of feedback mechanisms to explain your answer.

Answer 1