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Structure of a Pancreatic Beta Cell

Pancreatic beta cells constitute the predominant type of cells in the pancreas, which secretes a hormone called insulin. Insulin regulates the storage of glycogen in the liver and accelerates the oxidation of sugar in cells. So, deterioration of beta cells often results in type I or insulin-dependent diabetes. The pancreas is an elongated exocrine gland located just behind the stomach. Within the pancreas, there are clusters of cells that form the endocrine part of that organ, called the islets of Langerhans. Beta cells are most prevalent in the islets.

  1. Significance

    • Pancreatic beta cells generate and release a hormone called insulin that is essential especially for the metabolism of carbohydrates and the regulation of glucose levels in the blood (blood sugar). Another hormone, called C-peptide, is released in the bloodstream during the production of insulin in pancreatic beta cells, giving resistance against neuropathy and other nervous diseases.

    Structure

    • Pancreatic beta cells are anatomically and functionally different from pancreas endocrine tissue (unlike beta cells, pancreas endocrine tissue secretes pancreatic enzymes), and they produce insulin and glucagon. The number of pancreatic beta cells varies from hundreds to thousands of cells. Their total weight is only 1 to 2 g, and they make up just 1 to 2 percent of the total mass of the pancreas.

    Features

    • The clusters of pancreatic beta cells are enclosed by several types of cells such as alpha cells which secrete glucagon (a hormone whose function is opposite to that insulin; it helps to increase blood sugar level in the blood), delta cells that secrete somatostatin (a neurohormone that inhibits the secretion of insulin) and PP cells that secrete pancreatic polypeptide. All these cells are connected with each other via extracellular spaces and gap junctions so they can send out cellular products between them.

    Identification

    • Pancreatic beta cells lack uniformity in size. The diameters of the smallest and largest beta cells are 50 and 300 micrometers, respectively.

    Function

    • Pancreatic beta cells do not simultaneously produce and release insulin into the blood. Under the condition of high glucose level, stored insulin is set free in order to restore the normal glucose level in the blood. Pancreatic beta cells also release amylin, which is a hormonal constituent of the pancreas. The function of amylin, or islet amyloid polypeptide (IAPP), is the regulation of the effect of different foods on blood sugar levels.

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