AP BIOLOGY

Detailed explanation-1: -Insulin is secreted by the -cells of the pancreatic islets of Langerhans in response to elevation of the intracellular Ca2+ concentration ([Ca2+]i).

Detailed explanation-2: -Insulin is released by the ‘beta cells’ in the islets of Langerhans in response to food. Its role is to lower glucose levels in the bloodstream and promote the storage of glucose in fat, muscle, liver and other body tissues. ‘Alpha cells’ in the islets of Langerhans produce another important hormone, glucagon.

Detailed explanation-3: -Insulin is a peptide hormone composed of 51 amino acids that is synthesized, packaged, and secreted in pancreatic beta cells.

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: -Insulin is normally secreted by the beta cells (a type of islet cell) of the pancreas. The stimulus for insulin secretion is a high blood glucose-it’s as simple as that. Although there is always a low level of insulin secreted by the pancreas, the amount secreted into the blood increases as the blood glucose rises.