Definition: The proximal (lateral) two fifths of the small intestine, about 8 feet in length, between the duodenum and the ileum. The jejunum is distinct from the ileum in being more proximal, of larger diameter with a thicker wall, having larger, more highly developed circular folds (plicae circulares), being more vascular (redder in appearance), with the jejunal arteries forming fewer tiers of arterial arcades and longer vasa recta.
[L. jejunus, empty]
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Examples: glitazone, GI cocktail, etc.