Examine individual changes

'In human [[anatomy]], the '''intestine''' (or '''bowel''') is the segment of the [[Gastrointestinal tract|alimentary canal]] extending from 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 (anatomy)|colon]].<ref>{{cite book | last = Maton | first = Anthea | authorlink = | coauthors = Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright | title = Human Biology and Health | publisher = Prentice Hall | date = 1993 | location = Englewood Cliffs, New Jersey, USA | pages = | url = | doi = | id = | isbn = 0-13-981176-1}}</ref> ==Structure and function== [[Image:Stomach colon rectum diagram.svg|right]] 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. Grayish-purple in color and about 35 millimeters (1.5&nbsp;inches) in diameter, the small intestine is the first, measuring 6 to 7 meters (20–23&nbsp;ft) long average in an adult man. Shorter and relatively stockier, the large intestine is a dark reddish color, measuring roughly 1.5 meters (5 ft) long on average.<ref>{{cite web |url=http://hypertextbook.com/facts/2001/AnneMarieThomasino.shtml|title=Length of a Human Intestine|accessdate=2 September 2009}}</ref> People will have different sized intestines according to their size and age. The [[Lumen (anatomy)|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. [[File:Gut wall.svg|thumb|left|300px|The general structure of the intestinal wall]] *Along the whole length of the gut in the [[glandular epithelium]] are [[goblet cell]]s. These secrete [[mucus]] which lubricates the passage of food along and protects it from digestive enzymes. [[Intestinal villus|Villi]] are vaginations (folds) of the [[Mucous membrane|mucosa]] and increase the overall surface area of the intestine while also containing a [[lacteal]], which is connected to the [[Lymphatic system|lymph system]] and aids in the removal of [[lipid]]s and tissue fluid from the blood supply. Microvilli are present on the epithelium of a villus and further increase the surface area over which absorption can take place. *The next layer is the muscularis mucosa which is a layer of smooth muscle that aids in the action of continued [[peristalsis]] and [[catastalsis]] along the gut. The [[Gastrointestinal tract#Submucosa|submucosa]] contains nerves (e.g. [[Meissner's plexus]]), blood vessels and elastic fibre with collagen that stretches with increased capacity but maintains the shape of the intestine. *Surrounding this is the [[Gastrointestinal tract#Muscularis externa|muscularis externa]] which comprises longitudinal and smooth muscle that again helps with continued peristalsis and the movement of digested material out of and along the gut. In between the two layers of muscle lies [[Auerbach's plexus]]. *Lastly there is the [[Serous membrane|serosa]] which is made up of loose connective tissue and coated in mucus so as to prevent friction damage from the intestine rubbing against other tissue. Holding all this in place are the [[Mesentery|mesenteries]] which suspend the intestine in the abdominal cavity and stop it being disturbed when a person is physically active. The large intestine hosts several kinds of [[bacteria]] that deal with molecules the human body is not able to break down itself.{{fact|date=September 2010}} 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== *[[Gastroenteritis]] is an inflammation of the intestines. It is the most common disease of all the intestines. *[[Ileus]] is a blockage of the intestines. *[[Ileitis]] is an inflammation of the [[ileum]]. *[[Colitis]] is an inflammation of the [[large intestine]]. *[[Appendicitis]] is inflammation of the [[vermiform appendix]] located at the caecum. This is a potentially fatal disease if left untreated; most cases of appendicitis require surgical intervention. *[[Coeliac disease]] is a common form of [[malabsorption]], affecting up to 1% of people of northern European descent. An autoimmune response is triggered in intestinal cells by digestion of gluten proteins. Ingestion of proteins found in wheat, barley and rye, causes villous atrophy in the small intestine. Life-long dietary avoidance of these foodstuffs in a gluten-free diet is the only treatment. *[[Crohn's disease]] and [[ulcerative colitis]] are examples of [[inflammatory bowel disease]]. While Crohn's can affect the entire gastrointestinal tract, ulcerative colitis is limited to the large intestine. Crohn's disease is widely regarded as an [[autoimmunity|autoimmune disease]]. Although ulcerative colitis is often treated as though it were an autoimmune disease, there is no consensus that it actually is such. (See [[List of autoimmune diseases]]). *[[Enteroviruses]] are named by their transmission-route through the intestine (''enteric'' meaning intestinal), but their symptoms aren't mainly associated with the intestine. *[[Irritable bowel syndrome]] (IBS) is the most common [[functional disorder]] of the intestine. Functional constipation and [[chronic functional abdominal pain]] are other disorders of the intestine that have physiological causes, but do not have identifiable structural, chemical, or infectious pathologies. They are aberrations of normal bowel function but not diseases. *[[Diverticular disease]] is a condition that is very common in older people in industrialized countries. It usually affects the large intestine but has been known to affect the small intestine as well. [[Diverticulosis]] occurs when pouches form on the intestinal wall. Once the pouches become inflamed it is known as [[diverticulitis]]. *[[Endometriosis]] can affect the intestines, with similar symptoms to IBS. *[[Bowel twist]] (or similarly, bowel strangulation) is a comparatively rare event (usually developing sometime after major bowel surgery). It is, however, hard to diagnose correctly, and if left uncorrected can lead to bowel [[infarction]] and death. (The singer [[Maurice Gibb]] is understood to have died from this.) * [[Angiodysplasia]] of the colon * [[Chronic functional abdominal pain]] * [[Colorectal cancer]] * [[Constipation]] * [[Diarrhea]] * [[Hirschsprung's disease]] (aganglionosis) * [[Intussusception (medical disorder)|Intussusception]] * [[Polyp (medicine)]] (see also [[Colorectal polyp]]) * [[Pseudomembranous colitis]] * [[Ulcerative colitis]] and [[toxic megacolon]] ==In non-human animals== {{Expand section|date=December 2009}} 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 {{linktext|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== {{Wiktionary}} *[[Inflammatory bowel disease]] (or "IBD") *[[Diarrhea]] *[[Constipation]] BOWEL PICKING IS GOOD FOR YOU, AS YOU DON'T EAT IT! MOIST! ==References== {{No footnotes|date=June 2008}} {{reflist}} * [http://www.britannica.com/eb/article-9002491/intestine Encyclopædia Britannica article on intestine] retrieved on 2007-03-27 {{digestive_system}} [[Category:Digestive system]] [[Category:Gastroenterology]] [[Category:Offal]] [[ar:أمعاء]] [[arc:ܡܥܝܐ]] [[ca:Intestí]] [[cs:Střevo]] [[cy:Coluddion]] [[da:Tarm (anatomi)]] [[de:Darm]] [[el:Έντερο]] [[es:Intestino]] [[eo:Intesto]] [[eu:Heste]] [[fa:روده]] [[fr:Intestin]] [[ko:창자]] [[hi:आंत]] [[io:Intestino]] [[id:Usus]] [[it:Intestino]] [[he:מעיים]] [[pam:Bituka]] [[ht:Zantray]] [[la:Intestinum]] [[lt:Žarnynas]] [[nl:Ingewanden]] [[ja:腸]] [[oc:Intestin]] [[pl:Jelito]] [[pt:Intestino]] [[qu:Ch'unchul]] [[ru:Кишечник]] [[sah:Оhоҕос]] [[sq:Zorra]] [[simple:Intestine]] [[sl:Črevo]] [[su:Peujit]] [[fi:Suolisto]] [[sv:Tarm]] [[tl:Bituka]] [[th:ลำไส้]] [[uk:Кишечник]] [[vec:Budele]] [[fiu-vro:Sooliguq]] [[yi:געדערעם]] [[zh:腸臟]]'