Pancreatic islet

A pancreatic islet is a cluster of endocrine cells that releases hormones into the bloodstream. Its cell types coordinate blood-glucose regulation and other metabolic processes.

Beta cell: A pancreatic endocrine cell that produces and secretes insulin. Beta cells are the islet’s main source of insulin, which lowers blood glucose.
Glucose-stimulated insulin secretion: The process by which rising glucose triggers pancreatic beta cells to release insulin. It explains how islets translate a meal-related glucose rise into a hormone response.
Type 1 diabetes: An autoimmune disease in which pancreatic beta cells are destroyed, causing severe insulin deficiency. Loss of beta cells disrupts the insulin-producing function of pancreatic islets.
Pancreas: An abdominal organ that produces digestive enzymes and hormones including insulin and glucagon. Pancreatic islets are endocrine structures embedded within this organ’s exocrine tissue.
Alpha cell: A pancreatic endocrine cell that produces and secretes glucagon. Alpha cells counter falling blood glucose by releasing glucagon.
Glucagon: A hormone that raises blood glucose by promoting glucose production and release, mainly in the liver. Alpha cells release it when glucose is low, opposing insulin’s effect.
Type 2 diabetes: A metabolic disease involving insulin resistance and, over time, inadequate insulin secretion. Islet beta cells may fail to meet the body’s increased insulin demand.
Endocrine system: A network of glands and hormone-producing cells that regulates body functions through circulating chemical signals. Islets are one endocrine organ component among glands distributed throughout the body.
Delta cell: A pancreatic endocrine cell that produces somatostatin. Delta cells locally restrain the secretion of insulin and glucagon.
Paracrine signaling: Cell signaling in which secreted molecules act on nearby cells. Islet hormones can regulate neighboring endocrine cells before entering the circulation.

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