Small islands of Langerhans

See also: Small island (homonymy)

The small islands of Langerhans are endocrine cells (producing hormones) Pancréas gathered in small island S disseminated between the Acinus séreux (round cavities leading to the pancreatic channel.)

These small islands were discovered in 1868 by the German biologist Paul Langerhans (1847-1888). The small islands of Langerhans account for approximately 1 to 2% of the mass of the pancreas, that is to say 1 to 1,5 grams. An adult has between 750.000 and 1.500.000 small islands, the majority located at the back of the pancreas. Of a size ranging between 50 and 900 µm, the small island thus consists of some cells for the smallest small islands, and of approximately 5000 cells for largest.

The hormones produced by the small islands of Langerhans are secreted directly in blood circulation by at least 4 types of cells:

the Insuline is produced by beta (65-80% of the small islands)
the Glucagon is produced by alpha (15-20%)
the Somatostatine is produced by the delta (3-10%)
the pancreatic Polypeptide by the cells F (or PP) (1%).

The insular cells can be influenced by a communication autocrine and paracrine. Thus, insulin can it control its own biosynthesis, via receivers with insulin on the cell beta itself, but also on the biosynthesis of the close insular cells within the small island.

Insulin: Activates beta concealments and inhibits alpha concealments. Glucagon: Activates beta concealments and delta concealments. Somatostatin: Inhibits alpha concealments and beta concealments. Electrical activity off pancreatic islets has been studied using patch clamp technical, and it has turned out that the behavior off concealments in intact islets differs significantly from the behavior off dispersed concealments. -->

Internal bonds

not to confuse with the cells of Langerhans which are dendritic cells presenters of Antigène S that one finds in cutaneous fabric, the lymphatic ganglia
Glycémie and Régulation of the glycemia
Hormone

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