Human Gastrointestinal Tract

The human gastrointestinal tract is the stomach and intestine, sometimes including all the structures from the mouth to the anus. (The "digestive system" is a broader term that includes other structures, including the accessory organs of digestion).

In an adult male human, the gastrointestinal (GI) tract is 5 metres (20 ft) long in a live subject, or up to 9 metres (30 ft) without the effect of muscle tone, and consists of the upper and lower GI tracts. The tract may also be divided into foregut, midgut, and hindgut, reflecting the embryological origin of each segment of the tract.

The GI tract always releases hormones to help regulate the digestion process. These hormones, including gastrin, secretin, cholecystokinin, and grehlin, are mediated through either intracrine or autocrine mechanisms, indicating that the cells releasing these hormones are conserved structures throughout evolution.

Read more about Human Gastrointestinal Tract:  Upper Gastrointestinal Tract, Lower Gastrointestinal Tract, Embryology, Transit Time, Pathology, Immune Function, Histology

Famous quotes containing the words human and/or tract:

    ... geometry became a symbol for human relations, except that it was better, because in geometry things never go bad. If certain things occur, if certain lines meet, an angle is born. You cannot fail. It’s not going to fail; it is eternal. I found in rules of mathematics a peace and a trust that I could not place in human beings. This sublimation was total and remained total. Thus, I’m able to avoid or manipulate or process pain.
    Louise Bourgeois (b. 1911)

    Mr. Bok is giving the bird sanctuary as a tract of land at this place. He is dedicating it as a bird sanctuary and putting up these bells to interest the birds in music.
    Calvin Coolidge (1872–1933)