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ileum

ileum The section of the small intestine beyond the duodenum and the jejunum, and ending where it joins the caecum. Digestion is mostly completed before this point, but absorption into the blood of the resulting simpler substances continues here. The surface area of the lining is increased (though less than in the jejunum) by its folds and protrusions (villi). The last part of the ileum has a unique and essential function in the absorption of vitamin B12, necessary for normal blood formation.

Stuart Judge


See alimentary system.

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ileum

il·e·um / ˈilēəm/ • n. (pl. il·e·a / ˈilēə/ ) Anat. the third portion of the small intestine, between the jejunum and the cecum. DERIVATIVES: il·e·ac / -ˌak/ adj. il·e·al / -əl/ adj.

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ileum

ileum The portion of the mammalian small intestine that follows the jejunum and precedes the large intestine. It is a site of digestion and absorption. The internal lining of the ileum bears numerous small outgrowths (see villus), which increase its absorptive surface area.

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ileum

ileum (il-iŭm) n. the lowest of the three portions of the small intestine (see intestine). It runs from the jejunum to the ileocaecal valve.
ileal, ileac adj.

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ileum

ileum Major part of the small intestine, c.4m (13ft) long. Its inner wall is lined with finger-like villi, which increase the area for the absorption of nutrients.

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ileum

ileum Last portion of the small intestine, between the jejunum and the colon (large intestine); see gastro‐intestinal tract.

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ileum

ileum In Mammalia, the final part of the small intestine.

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ileum

ileum: see intestine.

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