peritoneum

peritoneum

a thin translucent serous sac that lines the walls of the abdominal cavity and covers most of the viscera

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

peritoneum

[‚per·ə·tə′nē·əm]

(anatomy)

The serous membrane enveloping the abdominal viscera and lining the abdominal cavity.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Peritoneum

 

a thin, semitransparent membrane with a smooth, shiny surface that lines the interior wall of the abdominal cavity and covers the organs inside it in vertebrate animals and humans.

In the normal state, the cavity between the parietal and visceral peritoneums is filled with serous fluid, which facilitates the shifting of organs in relation to each other and the abdominal wall. The total area of the peritoneum in an adult human is approximately 1.6-2.04 sq m (16,000-20,400 sq cm), and its thickness is 0.7-1.1 mm. The outer layer of the peritoneum is formed of mesothelium, and its base is composed of fibrous connective tissue. The peritoneum that covers internal organs (visceral peritoneum) is compactly knitted with them; the peritoneum covering the abdominal wall (parietal peritoneum) is united with underlying parts by an interlayer of loose connective tissue or subperitoneal fatty tissue. The diaphragmatic peritoneum lacks such an interlayer. The peritoneum is abundantly supplied with blood and lymph vessels and nerves.

Covering the wall of the abdominal cavity and the organs inside it, the peritoneum forms a system of slitlike spaces— the peritoneal cavity, which is completely closed in men and which communicates with the external environment through the opening of the Fallopian tube in women. Going from organ to organ and from organ to the wall of the abdominal cavity, the peritoneum forms ligaments, mesenteries, omenta, pouches, pits, and folds. Internal organs may penetrate through depressions in the transperitoneal space, forming hernias. Internal organs may be covered with peritoneum on all sides (intraperitoneally), on three sides (mesoperitoneally), or on only one side (extraperitoneally). Depending on the disposition of blood and lymph vessels, sections of peritoneum that primarily absorb or secrete serous fluid are distinguished; this conditions the circulation of fluid in the peritoneal cavity. In some sections of the peritoneum (on the diaphragm, in the pelvic cavity, and other sections) are located special apparatus, so-called pipes of the peritoneum, which assure especially intensive absorption of fluids. Of diseases of the peritoneum, the most dangerous is its inflammation—peritonitis.

IU. I. DENISOV-NIKOL’SKII

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.