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| Jejunum |
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| Small intestine |
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| Superior and inferior duodenal fossæ. |
| Gray's |
subject #248 1170 |
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 2-8m (6' 7"-26' 3") long; 1-2 m 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.
[edit] Villi
Transmission electron microscope (TEM) of Human
Jejunum
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. 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.
[edit] Etymology
Jejunum is derived from the adjective jejune, which means "fasting" or "hungry" in Early Modern English. The original meaning of the term was derived from the Greeks and Romans who found this section of the intestines "empty" following death [Latin: jejunus, empty]
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