ileum

(noun)

The last, and usually the longest, division of the small intestine; the part between the jejunum and large intestine.

Related Terms

Examples of ileum in the following topics:

  • Anatomy of the Small Intestine

    • The villi in the jejunum are much longer than in the duodenum or ileum.
    • The ileum is the final section of the small intestine.
    • The function of the ileum is mainly to absorb vitamin B12, bile salts, and any products of digestion that were not absorbed by the jejunum.
    • The ileum has an extremely large surface area both for the adsorption of enzyme molecules and for the absorption of products of digestion.
    • An illustration of the small intestine with the duodenum, jejunum, and ileum labeled.

  • Histology of the Small Intestine

    • The jejunum and ileum do not have Brunner's glands in the submucosa, while the ileum has Peyer's patches in the mucosa, but the duodenum and jejunum do not.
    • They are aggregations of lymphoid tissue that are found in the lowest portion of the small intestine, which differentiate the ileum from the duodenum and jejunum.

  • Anatomy of the Digestive System

    • Jejunum: This is the midsection of the intestine, connecting the duodenum to the ileum.
    • Ileum: This has villi, where all soluble molecules are absorbed into the blood ( through the capillaries and lacteals).

  • Development of Metabolism

    • This diagram indicates the ileum, jejunum, and duodenum.

  • Absorption in the Small Intestine

    • Absorption of the majority of nutrients takes place in the jejunum, with the following notable exceptions: iron is absorbed in the duodenum; vitamin B12 and bile salts are absorbed in the terminal ileum; water and lipids are absorbed by passive diffusion throughout the small intestine; sodium bicarbonate is absorbed by active transport and glucose and amino acid co-transport; and fructose is absorbed by facilitated diffusion.

  • False and True Pelves

    • The false pelvis supports the intestines (specifically, the ileum and sigmoid colon), and transmits part of their weight to the anterior wall of the abdomen.

  • Yolk Sac Development

    • Sometimes, a narrowing of the lumen of the ileum is seen opposite the site of attachment of the duct.

  • Aging and the Digestive System

    • Several aspects of the digestive tract are labeled in this diagram, including the mouth, large intestine (colon), rectum, anus, ileum, small intestine, stomach, and esophagus.

  • Digestive System Development

    • The midgut is the lower duodenum, leading to the first two-thirds of the transverse colon, jejunum, ileum, cecum, appendix, ascending colon, and first two-thirds of the transverse colon.

  • Mucosa

    • In the small intestine, the epithelium (particularly the ileum) is specialized for absorption, with villi and microvilli increasing surface area.