Islets of Langerhans

**Definition:** Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.

**Tree numbers:** - A03.734.414 - A06.300.414

**Synonyms:** - Nesidioblasts - Pancreas, Endocrine - Islet Cells - Pancreatic Islets - Islands of Langerhans