Mesentery 637855 218814355 2008-06-12T08:19:59Z Ghirlandajo 147410 /* External links */ ru: {{Infobox Anatomy | Name = Mesentery | Latin = | GraySubject = 246 | GrayPage = 1157 | Image = Gray1038.png | Caption = Horizontal disposition of the peritoneum in the lower part of the abdomen. The mesentery is marked with red.| Image2 = Gray1035.png | Caption2 = Vertical disposition of the peritoneum. Main cavity, red; omental bursa, blue. | Width = 300 | System = | MeshName = Mesentery | MeshNumber = A01.047.025.600.451 | }} 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 [[nerve]]s. 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: * Mesentery (proper) - surrounds parts of the [[small intestine]] (the [[jejunum]] and the [[ileum]]) * Mesocolon - surrounds parts of the [[Colon (anatomy)|colon]] ** [[Meso-appendix]] - peritoneum of the [[vermiform appendix]] ** [[Transverse mesocolon]] - peritoneum of the [[transverse colon]] ** [[Sigmoid mesocolon]] - peritoneum of the [[sigmoid colon]] * [[Broad ligament of the uterus]] - peritoneum of the [[uterus]], [[uterine tube]]s, and [[ovaries]] 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 [[invertebrate]]s, the term '''mesentery''' is used for any tissue that divides the body cavity ([[coelom]]) into partitions. ==Additional images== <gallery> Image:Gray54.png|Figure obtained by combining several successive sections of a human embryo of about the fourth week. Image:Gray985.png|Abdominal part of digestive tube and its attachment to the primitive or common mesentery. Human embryo of six weeks. </gallery> ==External links== * {{SUNYAnatomyLabs|39|01|01|00}} * {{NormanAnatomy|jejunumileum}} * [http://learning.mgccc.cc.ms.us/science/cat/sld048.htm McGill] * {{GPNotebook|-1724579760}} {{Peritoneum}} {{Development of digestive system}} [[Category:Digestive system]] [[Category:Abdomen]] [[ca:Transcavitat dels epiplons]] [[de:Gekröse]] [[es:Mesenterio]] [[fr:Mésentère]] [[it:Mesentere]] [[pl:Krezka jelita cienkiego]] [[ru:Брыжейка]]