AP BIOLOGY

Detailed explanation-1: -Glucagon is a peptide hormone secreted from the alpha cells of the pancreatic islets of Langerhans. Hypoglycemia is physiologically the most potent secretory stimulus and the best known action of glucagon is to stimulate glucose production in the liver and thereby to maintain adequate plasma glucose concentrations.

Detailed explanation-2: -The secretion of glucagon by pancreatic -cells plays a critical role in the regulation of glycaemia. This hormone counteracts hypoglycaemia and opposes insulin actions by stimulating hepatic glucose synthesis and mobilization, thereby increasing blood glucose concentrations.

Detailed explanation-3: -The -cells secrete glucagon as a response to low blood glucose. The major function of glucagon is to release glucose from the glycogen stores in the liver.

Detailed explanation-4: -While the beta cell produces insulin, the only blood glucose-lowering hormone of the body, the alpha cell releases glucagon, which elevates blood glucose. Under physiological conditions, these two cell types affect each other in a paracrine manner.

Detailed explanation-5: -It is produced by the alpha cells, found in the islets of Langerhans, in the pancreas, from where it is released into the bloodstream. The glucagon-secreting alpha cells surround the insulin-secreting beta cells, which reflects the close relationship between the two hormones.