Enterocytes are the cells that line the small intestine absorbing all the bodies nutrients and fluids and protecting against pathogenic bacteria, helping maintain the immune function of the gastrointestinal tract. Without direct nutrition enterocytes atrophy within as little as 90minutes, and so 24hrs to 72hrs fasting can have a devastating effect to the integrity and motility of the GI barrier.

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Know the cells of the Gastrointestinal tract:

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• The intestinal epithelium is made up of four major types of cells – enterocytes, mucous cells, enteroendocrine cells and Paneth cells. These four cell types all originate from stem cells located in the ‘valleys at the bottom of the villi, named the crypts of Lieberkuhm.

• Secondary digestion and absorption of nutrient molecules takes place in the small intestine through a layer of finger-like villi.

• Enterocytes are simple, column-shaped epithelial cells found in the small intestine and also the colon. they are also known as ‘surface absorptive cells’ and are the workhouses of the intestine. Enterocytes are coontinuously formed and replenished from the stem cells that are located in the crypts between the villi. Enterocytes are ‘born’ at the bottom of the villus and take 2-5 days to slowly migrate up to the apex of the villus. Once they reach the apex, they are programmed to die. In contrast, red blood cells live for about 3 months in the circulation.

• Enterocytes are responsible for absorbing sugars, amino acids, water and electrolytes. They adhere tightly to eachother and therefore also serve as a physical barrier that prevents food and bacteria in the intestinal lumen from migrating freely into the systematic circulation.

• Each enterocyte also forms numerous tiny folded extensions of its cell membrane, about 1 micrometer long, that are termed microvilli or ‘striated border’. These folds increase the surface area for absorption. Enzymes located in these microvilli break down sugars and proteins into their final forms, ready for absorption and transport through the enterocyte.

• Mucous cells release mucin that acts as a protective barrier for the villi.

• Enteroendocrine cells are scatter throughout the stomach, pancreas and small intestine. They are responsible for producing various hormones that control gastroinintestinal functions, such as gastrin, chloecystokinin, insulin and glycagon.

• Paneth cells are the guardians for the stem cells. They can release substances that causelysis of bacteria. Paneth cells actually live for about 3 weeks and are located in the crypts.