Question

One role of the pancreas is to help regulate blood glucose levels. Two types of cells in the pancreas, beta and alpha, serve as sensors to detect changes in blood glucose levels. High glucose levels cause beta cells to increase the amount of insulin given off by the pancreas. The insulin triggers body cells to take in glucose and the liver to store excess glucose as glycogen, decreasing the blood glucose level. On the other hand, low glucose blood levels trigger alpha cells to signal for glycogen to free up stored glucose from your liver, thus increasing the blood glucose level.
What type of feedback mechanism is this, positive or negative? Explain your answer based on the description of the mechanism.
Blood glucose levels change throughout the day. What causes these changes, and how do these feedback cycles work together to maintain a dynamic homeostasis.
Predict what will happen to this feedback mechanism and then to a person’s body if the beta cells are destroyed by an autoimmune disease.

Answer 1

1. Regulation of glucose blood levels is an example of negative feedback mechanism.

Negative feedback mechanism is a control mechanism involved in homeostasis maintain, in this case maintenance of glucose blood levels in normal range.

Negative feedback mechanism contains sensory system that detects the changes, control system that responds to change and activates mechanisms of effector system that reverse the changes in order to restore conditions to their normal levels.

• Pancreatic cells-sensors

• Insulin-control system

• Body cells- effector cells

2. Blood glucose levels change throughout the day because of the food consumption, but in healthy individuals levels of glucose are successfully regulated via the mechanism of hormones such as insulin and glucagon in a process called glucose blood regulation.

This tight regulation of pancreatic hormones is referred to as glucose homeostasis. Insulin lowers blood sugar and glucagon raises it.

3. If the beta cells are destroyed by an autoimmune disease (immune system attacks its own cells), there would be no insulin release, and consequently, the glucose blood levels would be increased.

Diabetes type I is a metabolic disorder caused by the destruction of insulin-producing pancreatic beta cells.