AskDefine | Define mesentery

Dictionary Definition

mesentery n : a double layer of peritoneum that attaches to the back wall of the abdominal cavity and supports the small intestines

User Contributed Dictionary

English

Etymology

From μέσος + έντερον

Noun

  1. The membrane that attaches the intestines to the wall of the abdomen, maintaining their position in the abdominal cavity, and supplying them with blood vessels, nerves, and lymphatics.

Derived terms

Translations

the membrane that attaches the intestines to the wall of the abdomen
  • Norwegian: mesenterium

Extensive Definition

In anatomy, a mesentery is the double layer of peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen. Its meaning, however, is frequently extended to include double layers of peritoneum connecting various components of the abdominal cavity.

Mesentery (proper)

The mesentery proper (i.e. the original definition) refers to the peritoneum responsible for connecting the jejunum and ileum, parts of the small intestine, to the back wall of the abdomen. Between the two sheets of peritoneum are blood vessels, lymph vessels, and nerves. This allows these parts of the small intestine to move relatively freely within the abdominopelvic cavity. The brain, however, cannot map sensation accurately, so sensation is usually referred to the midline, an example of referred pain.

Development

The mesentery is derived from what is known in the embryo as the dorsal mesentery. The dorsal mesentery is larger than the ventral mesentery, which gradually becomes other parts of the peritoneum. Most parts of the ventral mesentery are associated with the liver.

Mesentery (general)

Mesenteries are composed of two layers of peritoneum. The peritoneum that lies on the walls of the abdominopelvic cavity (parietal peritoneum) invaginates at certain parts, with an organ inside this invagination. This invaginated peritoneum (visceral peritoneum) will often surround all but a part of the organ ("bare area"), through which the organ transmits blood vessels and nerves. If this organ is invaginated far enough into the peritoneum, the visceral peritoneum will come in contact with itself, forming the organ's mesentery.
Mesenteries in the body: The fetal pig is considered a good reference for this subject.

Pathology

A lack of blood-supply to the mesentery causes mesenteric ischemia.

Invertebrate anatomy

In invertebrates, the term mesentery is used for any tissue that divides the body cavity (coelom) into partitions.

Additional images

External links

mesentery in Catalan: Transcavitat dels epiplons
mesentery in German: Gekröse
mesentery in Spanish: Mesenterio
mesentery in French: Mésentère
mesentery in Italian: Mesentere
mesentery in Polish: Krezka jelita cienkiego
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