Endothelium
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222179942
2008-06-27T23:16:07Z
WadeSimMiser
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Reverted edits by [[Special:Contributions/66.161.125.41|66.161.125.41]] to last version by 192.35.79.70 (using [[WP:HG|Huggle]])
[[Image:Anatomy_artery.png|thumb|350px||right|Diagram showing the location of endothelial cells]]
{{dablink|This article is about the lining of [[blood vessel]]s. For the endothelium of the [[cornea]], see [[corneal endothelium]]}}
The '''endothelium''' is the thin layer of [[cell (biology)|cells]] that line the interior surface of [[blood vessel]]s, forming an interface between circulating [[blood]] in the [[lumen (anatomy)|lumen]] and the rest of the vessel wall. Endothelial cells line the entire [[circulatory system]], from the [[heart]] to the smallest [[capillary]]. These cells reduce [[turbulence]] of the flow of blood allowing the fluid to be pumped farther.
Endothelial tissue is a specialized type of [[epithelium]] tissue (one of the four types of [[biological tissue]] in animals). More specifically, it is [[Squamous epithelium|simple squamous epithelium]].
Endothelium of the interior surfaces of the heart chambers are called [[endocardium]]. Both blood and lymphatic capillaries are composed of a single layer of endothelial cells.
==Function==
Endothelial cells are involved in many aspects of vascular biology, including:
* [[vasoconstriction]] and [[vasodilation]], and hence the control of [[blood pressure]]
* [[coagulation|blood clotting]] ([[thrombosis]] & [[fibrinolysis]])
* [[atherosclerosis]]
* formation of new blood vessels ([[angiogenesis]])
* [[inflammation]] and swelling ([[oedema]])
Endothelial cells also control the passage of materials — and the transit of [[white blood cell]]s — into and out of the bloodstream.
In some organs, there are highly differentiated endothelial cells to perform specialized 'filtering' functions. Examples of such unique endothelial structures include the [[glomerulus (kidney)|renal glomerulus]] and the [[blood-brain barrier]].
==Pathology==
''[[Endothelial dysfunction]]'', or the loss of proper endothelial function, is a hallmark for vascular diseases, and often leads to [[atherosclerosis]]. This is very common in patients with [[diabetes mellitus]], [[hypertension]] or other chronic pathophysiological conditions. One of the main mechanisms of endothelial dysfunction is the diminishing of [[nitric oxide]], often due to high levels of [[asymmetric dimethylarginine]], which interfere with the normal [[Arginine|L-arginine]]-stimulated [[Nitric oxide synthase|nitric oxide synthesis]].
==See also==
*[[Endothelium-derived relaxing factor]] ([[EDRF]])
*[[Robert F. Furchgott]] (1998 Nobel prize for discovery of EDRF)
*[[Caveolae]]
*[[Weibel-Palade body|Weibel-Palade bodies]]
*[[Endothelial microparticle]]s
*[[Endothelial progenitor cell|Endothelial progenitor cells]]
*[[Endocardium]]
*[[Tunica intima]]
*[[Apelin]]
*[[Susac's syndrome]]
==External links==
* {{eMedicineDictionary|endothelium}}
* {{UCDavisOrganology|Circulatory/vessels/capillaries1/capillaries3}} - "Capillaries, non-fenestrated (EM, Low)"
* {{BUHistology|21402ooa}}
* ''Endothelium: Journal of Endothelial Research'' [http://www.informaworld.com/smpp/title~content=t713617829]
==References==
* Molecular Biology of the CELL, 4th edition, Alberts et al., 2002
[[Category:Cardiovascular system]]
[[Category:Tissues]]
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