Pancreas

From Diabetes Wiki

The pancreas is an organ in the digestive and endocrine system that produces several important hormones, including insulin, glucagon and somatostatin.

There are two different types of tissue in the pancreas. The exocrine pancreas produces enzymes that break down digestible foods, while the endocrine pancreas secretes hormones that regulate blood glucose levels.

These hormone-producing cells are grouped together in the Islets of Langerhans, which make up approximately 1 to 2% of the pancreas. There are about one million islets in a healthy adult human pancreas, which are interspersed evenly throughout the organ, and their combined weight is 1 to 1.5 grams. Each islet contains approximately one thousand cells.

[edit] Cell types

Hormones produced in the Islets of Langerhans are secreted directly into the blood flow by (at least) four different types of cells:

• Beta cells ("B cells") producing insulin and amylin (65-80% of the islet cells)
• Alpha cells ("A cells") releasing glucagon (15-20%)
• Delta cells ("D cells") producing somatostatin (3-10%)
• PP cells containing polypeptide (1%)

The islets are crisscrossed by a dense network of capillaries, so that most endocrine cells can spill the hormones they produce directly into the tiny blood vessels.

[edit] Blood sugar regulation

Beta cells monitor the blood glucose level. As the glucose level rises, the pancreas produces more insulin, which stores the glucose in muscle and fat cells. As the glucose level falls, the pancreas slows down the release of insulin. This prevents hypoglycemia, or low blood glucose. At the same time, the alpha cells release glucagon, stimulating the liver begins to release glycogen from storage.