The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain its endocrine (hormone-producing) cells, discovered in 1869 by German pathological anatomist Paul Langerhans.

The pancreatic islets constitute 1 to 2% of the pancreas volume and receive 10–15% of its blood flow. The pancreatic islets are arranged in density routes throughout the human pancreas, and are important in the metabolism of glucose.

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