Islets of Langerhans

Clusters of cells within the pancreas that play a vital role in hormone production.

Islets of Langerhans are small clusters of endocrine cells located in the pancreas. They are responsible for the regulation of blood sugar levels through the secretion of hormones such as insulin and glucagon. These islets make up about 1-2% of the pancreatic mass and are composed of several types of cells, each producing different hormones that work in concert to maintain glucose homeostasis.

Terminologia Anatomica

insulae-pancreaticae

System

Endocrine system

Function

The primary function of the Islets of Langerhans is to regulate blood glucose levels, ensuring that the body has a steady supply of energy. Insulin, produced by beta cells within the islets, lowers blood sugar levels by promoting the uptake of glucose by the body’s cells and stimulating the liver to store glucose as glycogen. In contrast, glucagon, secreted by alpha cells, increases blood sugar levels by signaling the liver to release stored glucose back into the bloodstream when needed. The delicate balance between these hormones is crucial for preventing conditions like hypoglycemia and hyperglycemia, which can have serious health implications. Furthermore, the islets also produce somatostatin and pancreatic polypeptide, which help regulate the functions of both the endocrine and exocrine systems of the pancreas.

Location

The Islets of Langerhans are found scattered throughout the pancreas, which is located in the upper abdomen, behind the stomach. The pancreas itself is an elongated gland that extends horizontally across the abdomen, measuring about 15 centimeters in length. The islets are interspersed among the pancreas's exocrine tissue, which is involved in digestion. Typically, larger clusters of islets can be found in the tail of the pancreas, although they are present throughout the organ, highlighting the pancreas's dual role in both endocrine and digestive functions.

Did You Know?

The Islets of Langerhans were discovered in 1869 by the German pathologist Paul Langerhans.
There are approximately 1-2 million islets in a typical human pancreas, which collectively weigh about 1-2 grams.
Stress can affect the balance of hormones produced by the Islets of Langerhans, impacting blood sugar levels.
Diabetes mellitus is a result of dysfunction in the Islets of Langerhans, either through insufficient insulin production or insensitivity of body cells to insulin.