Jejunum

German: Jejunum

1 Definition

The jejunum is the 2-2.5 meters long middle part of the small intestine, situated between duodenum and ileum. Its structure is characterized by intestinal glands (crypts of Lieberkühn) and high circular folds.

2 Histology

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3 Properties

There is no structural border between jejunum and ileum (which forms the last part of the small intestine).

Like all hollow organs, the jejunum is lined with a mucous membrane. On the outside, the jejunum is covered with two layers of smooth muscles. The outermost, serous layer is formed by the peritoneum. The jejunum is connected to the posterior abdominal wall by its mesentery, the mesojejunum.

4 Blood supply

The jejunum receives arterial blood via the jejunal arteries from the superior mesenteric artery. The main veins of the jejunum are the jejunal veins which drain into the superior mesenteric vein.