Compilation of free information about human parts, their function, assembly, repair, and maintenance
Jejunum
| Jejunum | |
|---|---|
 |
|
| Small intestine | |
 |
|
| Superior and inferior duodenal fossæ. | |
| Gray's | subject #248 1170 |
| Artery | intestinal arteries |
| Nerve | celiac ganglia, vagus [1] |
| Precursor | midgut |
| MeSH | Jejunum |
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.
In adult humans, 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 villi, which increase the surface area of tissue available to absorb nutrients from the gut contents. The villi in the jejunum are much longer than in the duodenum or ileum.
It differs from the duodenum due to lack of Brunner's glands.
It is also different from the ileum due to fewer goblet cells and generally lacks Peyer's patches.
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[citaton needed][Latin: jejunus, fasting; barren]
Additional images
 Duodenojejunal fossa.
|
 Transmission electron microscope (TEM) of Human Jejunum
|
 TEM of Mouse Jejunum x14000
|
References
External links
- Gastrolab.net:The Jejunum
- Peyer's patches
- SUNY Labs 37:11-0100 - "Abdominal Cavity: The Jejunum and the Ileum"
- SUNY Anatomy Image 7856
|
[show]
|
|
|---|---|
| Upper gastrointestinal tract | Mouth • Pharynx (nasopharynx, oropharynx, hypopharynx) • Esophagus • Crop • Stomach (rugae, gastric pits, cardia/gland, fundus/gland, pylorus/gland, pyloric antrum) |
| Lower gastrointestinal tract |
Small intestine (duodenum, jejunum, ileum) • Vermiform appendix • Ileocecal valve Large intestine: Cecum • Colon (ascending colon, transverse colon, descending colon, sigmoid colon) • Rectum (Houston valve, rectal ampulla, pectinate line) • Anal canal (anal valves, anal sinuses, anal columns) Anus: Sphincter ani internus muscle • Sphincter ani externus muscle GALT: Peyer's patches • M cells intestinal villus • crypts of Lieberkühn • circular folds • taenia coli • haustra • epiploic appendix |
| | Digestive system |
The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Jejunum" modified December 8, 2006 with previous authors listed in its history.
