Intestine

In human anatomy, the intestine (or bowel) is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. In humans, the small intestine is further subdivided into the duodenum, jejunum and ileum while the large intestine is subdivided into the cecum and colon.[1]

Contents

Structure and function

The structure and function can be described both as gross anatomy and at a microscopic level. The intestinal tract can be broadly divided into two different parts, the small and large intestine. .[2] People will have different sized intestines according to their size and age.

The lumen is the cavity where digested food passes through and from where nutrients are absorbed. Both intestines share a general structure with the whole gut, and are composed of several layers. Going from inside the lumen radially outwards, one passes the mucosa (glandular epithelium and muscularis mucosa), submucosa, muscularis externa (made up of inner circular and outer longitudinal), and lastly serosa.

The large intestine hosts several kinds of bacteria that deal with molecules the human body is not able to break down itself. This is an example of symbiosis. These bacteria also account for the production of gases inside our intestine (this gas is released as flatulence when eliminated through the anus). However the large intestine is mainly concerned with the absorption of water from digested material (which is regulated by the hypothalamus) and the reabsorption of sodium, as well as any nutrients that may have escaped primary digestion in the ileum.

Diseases and disorders

In non-human animals

Animal intestines have multiple uses. From each species of livestock that is a source of milk, a corresponding rennet is obtained from the intestines of milk-fed calves. Pig and calf intestines are eaten, and pig intestines are used as sausage casings. Calf intestines supply Calf Intestinal Alkaline Phosphatase (CIP), and are used to make Goldbeater's skin.

See also

References

  1. ^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1. 
  2. ^ Thomasino.shtml "Length of a Human Intestine". http://hypertextbook.com/facts/2001/AnneMarice Thomasino.shtml. Retrieved 2 September 2009. 
  3. ^ http://www.irregularbowelsyndrome.info