Where Are the Islets of Langerhans?
These islets are not to be found in an atlas but are located in the human pancreas, which manufactures juices to aid the digestion of fats and continues the work of the saliva and gastric juices. Pancreatic islets, also called islets of Langerhans, are tiny clusters of cells scattered throughout the pancreas.
The pancreas is an organ about the size of a hand located behind the lower part of the stomach. Langerhans was a German anatomist (1847-88) who gave his name to two other parts of the body. He discovered cells in the epidermis called Langerhans Cells and also the Langerhans Layer which is a layer of the skin.
There are many groups of cells without ducts distributed through the pancreas. But the importance of the islets of Langerhans is that their beta cells are a source of insulin. It is damage to or removal of the islets of Langerhans that leads to pancreatic diabetes. Insulin, which is a protein, is synthesized by the beta cells.
There are about 3 million islets distributed in the form of density routes throughout the pancreas of a healthy adult human, each of which measures an average of about 0.1 mm (109 µm) in diameter. Each is separated from the surrounding pancreatic tissue by a thin fibrous connective tissue capsule which is continuous with the fibrous connective tissue that is interwoven throughout the rest of the pancreas. The combined mass of the islets is 2 grams.
Islets of Langerhans can also form super structures called Islet clusters which are composed of small islets that surround large blood vessels. The roundness of islets along the pancreas has also been quantified through the Index of Sphericity method. Thus, the islets closest to the spherical form are mainly found in the pancreas tail whereas the islets farthest from the spherical form are found in the pancreas neck.
When the level of blood glucose, also called blood sugar, rises after a meal, the pancreas responds by releasing insulin into the bloodstream. Insulin helps cells throughout the body absorb glucose from the bloodstream and use it for energy. Diabetes develops when the pancreas does not make enough insulin, the body’s cells do not use insulin effectively, or both. As a result, glucose builds up in the blood instead of being absorbed by cells in the body.
In type-1 diabetes, the beta cells of the pancreas no longer make insulin because the body’s immune system has attacked and destroyed them. The immune system protects people from infection by identifying and destroying bacteria, viruses, and other potentially harmful foreign substances.
A person who has type-1 diabetes must take insulin daily to live. Type-2 diabetes usually begins with a condition called insulin resistance, in which the body has trouble using insulin effectively. Over time, insulin production declines as well, so many people with type-2 diabetes eventually need to take insulin.