islet of Langerhans

The islets contain several hormone-secreting cell types: alpha cells (glucagon), beta cells (insulin, the most abundant type), delta cells (somatostatin), PP cells (pancreatic polypeptide), and epsilon cells (ghrelin). Each cell type regulates distinct metabolic functions.

Islets are endocrine structures that secrete hormones directly into the bloodstream, comprising about 1-2% of the pancreatic mass. The surrounding exocrine pancreas produces digestive enzymes secreted into the duodenum via ducts.

In type 1 diabetes, the immune system attacks and destroys the insulin-producing beta cells within the islets of Langerhans. This autoimmune destruction results in absolute insulin deficiency, requiring lifelong insulin therapy.