Islets

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Islets of Langerhans

The Islets of Langerhans are a group of cells in the pancreas that produce and secrete hormones. They were discovered in 1869 by German pathologist Paul Langerhans, after whom they are named. The islets are scattered throughout the pancreas and represent approximately 1-2% of the organ's mass.

Structure[edit | edit source]

The Islets of Langerhans are made up of four different types of cells: alpha cells, beta cells, delta cells, and PP cells. Each type of cell produces a different hormone.

  • Alpha cells (alpha cells) produce glucagon, a hormone that raises blood sugar levels.
  • Beta cells (beta cells) produce insulin, a hormone that lowers blood sugar levels.
  • Delta cells (delta cells) produce somatostatin, a hormone that inhibits the release of other hormones in the islet.
  • PP cells (PP cells) produce pancreatic polypeptide, a hormone that regulates the pancreas and digestive tract.

Function[edit | edit source]

The primary function of the Islets of Langerhans is to maintain normal blood glucose levels. They do this by producing and secreting insulin and glucagon, hormones that work together to regulate the amount of glucose in the blood.

When blood glucose levels are high, beta cells in the islets produce insulin, which signals cells in the body to take in glucose from the blood. When blood glucose levels are low, alpha cells in the islets produce glucagon, which signals the liver to release stored glucose into the blood.

Clinical significance[edit | edit source]

Dysfunction of the Islets of Langerhans can lead to a number of diseases, including diabetes mellitus (diabetes mellitus), a condition characterized by high blood glucose levels. In type 1 diabetes (type 1 diabetes), the body's immune system destroys the beta cells in the islets, leading to a lack of insulin. In type 2 diabetes (type 2 diabetes), the body's cells become resistant to insulin, and the beta cells in the islets may not produce enough insulin in response.

See also[edit | edit source]

References[edit | edit source]


Islets Resources
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Contributors: Prab R. Tumpati, MD