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Islets of Langerhans

Cell clusters in the pancreas that form the endocrine part of that organ; secrete insulin and other hormones. Cells found in the pancreas that are responsible for secreting insulin and glucagon. The endocrine region of the pancreas, i.e. pancreatic cells that produce hormones, mainly glucagon and insulin
The pancreas is a glandular structure that functions mainly for the production of pancreatic enzymes for digestion and of hormones such as insulin and glucagon. Its production of such hormones makes the pancreas a part of the endocrine system. The cells in the pancreas that carry out endocrine functions are the islets of Langerhans. The name came from the German anatomist, Paul Langerhans, who first described them in 1869. The islets of Langerhans make up about 4.5% of the pancreas.1

In humans, the two major cells of the islets are the alpha cells and the beta cells. The alpha cells produce glucagon whereas the beta cells make insulin. In type 1 diabetic individuals, the beta cells have become non-functional resulting in the insufficiency of insulin that regulates blood sugar levels.

The other cells that make up the islets of Langerhans include delta cells (producing somatostatin), gamma cells (producing polypeptide), and epsilon cells (producing ghrelin).

Word origin: named after Paul Langerhans, the German anatomist who first described it.


  • pancreatic islets


1 Ionescu-Tirgoviste, C., Gagniuc, P. A., Gubceac, E., Mardare, L., Popescu, I., Dima, S., & Militaru, M. (2015). “A 3D map of the islet routes throughout the healthy human pancreas”. Scientific Reports 5.

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