Jejunum
99608
212521316
2008-05-15T03:19:45Z
67.58.149.150
/* Internal structure */
{{Infobox Anatomy |
Name = {{PAGENAME}} |
Latin = |
GraySubject = 248 |
GrayPage = 1170 |
Image = Illu small intestine.jpg |
Caption = Small intestine |
Image2 = Gray1041.png |
Caption2 = Superior and inferior duodenal fossæ. |
Precursor = [[midgut]] |
System = |
Artery = [[jejunal arteries]] |
Vein = [[jejunal veins]] |
Nerve = [[celiac ganglia]], [[vagus]] <ref>{{GeorgiaPhysiology|6/6ch2/s6ch2_30}}</ref> |
Lymph = |
MeshName = Jejunum |
MeshNumber = A03.556.124.684.500 |
DorlandsPre = |
DorlandsSuf = |
}}
In [[anatomy]] of the [[digestive system]], the '''jejunum''' is the central of the three divisions of the [[small intestine]] and lies between the [[duodenum]] and the [[ileum]]. The change from the duodenum to the jejunum is usually defined as the [[ligament of Treitz]].
In adult [[human]]s, the small intestine is usually between 5.5-6m long, 2.5m of which is the jejunum.
The [[pH]] in the jejunum is usually between 7 and 8 (neutral or slightly [[alkaline]]).
The jejunum and the ileum are suspended by [[mesentery]] which gives the bowel great mobility within the [[abdomen]]. It also contains muscles to help move the food along.
==Internal structure==
The inner surface of the jejunum, its [[mucous membrane]], is covered in projections called [[villus|villi]], which increase the surface area of tissue available to absorb nutrients from the gut contents. The epithelial cells which line these villi possess even larger numbers of microvilli. The transport of nutrients across epithelial cells through the jejunum and ileum includes the [[passive transport]] of sugar fructose and the [[active transport]] of amino acids, small peptides, vitamins, and most glucose. The villi in the jejunum are much longer than in the duodenum or ileum.
The jejunum contains very few [[Brunner's glands]] (found in the duodenum) or [[Peyer's patches]] (found in the ileum). Instead, it has many large [[circular folds]] in its [[submucosa]] called plicae circulares which increase the surface area for nutrient absorption.
==Etymology==
''Jejunum'' is derived from the adjective ''jejune'', which means "[[fasting]]" or "hungry" in [[Early Modern English]].
It was so called because this portion of the intestine was found "empty" following death {{Fact|date=April 2007}}[Latin: jejunus, fasting; barren]
==Additional images==
<gallery>
Image:Gray1042.png|Duodenojejunal fossa.
Image:Microvilli.jpg|Transmission electron microscope (TEM) of Human [[Jejunum]]
Image:Nudemousejejunum_EM.jpg|TEM of Mouse Jejunum x14000
</gallery>
==References==
<references/>
==External links==
*[http://www.gastrolab.net/bb12je.htm Gastrolab.net:The Jejunum]
*[http://www.thehealthnews.org/news/06/08/01/Peyers.Patches.html Peyer's patches]
* {{SUNYAnatomyLabs|37|11|01|00}} - "Abdominal Cavity: The Jejunum and the Ileum"
* {{SUNYAnatomyImage|7|8|56}}
{{digestive_system}}
[[Category:Digestive system]]
{{digestive-stub}}
[[de:Jejunum]]
[[es:Yeyuno]]
[[eo:Jejuno]]
[[fa:تهیروده]]
[[fr:Jéjunum]]
[[id:Usus kosong]]
[[is:ásgörn]]
[[it:Digiuno (anatomia)]]
[[lt:Tuščioji žarna]]
[[hu:Jejunum]]
[[nl:Nuchtere darm]]
[[ja:空腸]]
[[pl:Jelito czcze]]
[[pt:Jejuno]]
[[sk:Lačník]]
[[sl:Tešče črevo]]
[[tr:Jejunum]]
[[zh:空腸]]