Question

Glucagon increases blood glucose levels by stimulating what?

O cells to make glycogen
O cells to break down muscle glycogen
O cells to break down liver glycogen
O liver and muscle cells to break down their glycogen stores
O cells to make glycogen

Answer 1

Glucagon increases blood glucose levels by stimulating the liver to break down glycogen into glucose. Released by the pancreas when blood glucose is low, glucagon's hyperglycemic effect helps maintain energy levels.

Step-by-step explanation:

Glucagon increases blood glucose levels by stimulating cells to break down liver glycogen into glucose, a process known as glycogenolysis.

The hormone glucagon is released by alpha cells of the pancreas when blood glucose levels fall. Glucagon’s primary role is to raise blood glucose levels to maintain a homeostatic balance. It triggers the liver to convert glycogen stores into glucose, which is then released into the bloodstream. This response is vital in maintaining energy supply between meals or during periods of high energy expenditure. While glucagon stimulates the breakdown of liver glycogen, it does not have a significant direct effect on muscle glycogen; instead, muscle glycogen is primarily broken down for local muscle use.

The breakdown of liver glycogen releases glucose into the bloodstream, thus glucagon has a hyperglycemic effect and is crucial for energy balance and metabolic homeostasis. This process allows glucose to be released into circulation and utilized as energy by muscle cells. Glucagon also stimulates the liver to convert amino acids into glucose, a process called gluconeogenesis, and prompts adipose cells to release fatty acids into the bloodstream.