How do insulin and glucagon work together to regulate blood glucose levels?

• A. Insulin raises blood glucose while glucagon lowers it
• B. Insulin promotes uptake and storage, glucagon stimulates breakdown
• C. Insulin and glucagon function independently of each other
• D. Insulin and glucagon both lower blood glucose levels

Answer: (B)

Insulin and glucagon play crucial and complementary roles in maintaining blood glucose homeostasis. Insulin is produced by the beta cells of the pancreas and functions primarily to lower blood glucose levels by promoting the uptake of glucose into cells, especially muscle and adipose tissues. This hormone stimulates processes such as glycogenesis (the conversion of glucose into glycogen for storage in the liver and muscles) and lipogenesis (the storage of fats), effectively reducing the amount of glucose circulating in the bloodstream.

On the other hand, glucagon, produced by the alpha cells of the pancreas, has the opposite effect. It acts to raise blood glucose levels by stimulating glycogenolysis (the breakdown of glycogen into glucose), gluconeogenesis (the production of glucose from non-carbohydrate sources), and the release of glucose into the bloodstream from the liver.

The regulation of blood glucose is a dynamic balance between these two hormones. When blood glucose levels are high after a meal, insulin helps to lower them. Conversely, when blood glucose levels drop, such as during fasting or prolonged periods without food, glucagon is released to increase glucose levels.

This partnership forms a feedback system that ensures blood glucose levels remain stable, demonstrating how insulin promotes uptake and storage while glucagon stimulates