The endothelium is the thin layer of cells that line the interior surface of
blood vessels, forming an interface between circulating bloodin the lumen and the rest of the vessel wall. Endothelial cells line the entire circulatory system, from the heartto the smallest capillary. These cells reduce turbulenceof the flow of blood allowing the fluid to be pumped farther.
Endothelial tissue is a specialized type of
epitheliumtissue (one of the four types of biological tissuein animals). More specifically, it is 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.
Endothelial cells are involved in many aspects of vascular biology, including:
vasoconstrictionand vasodilation, and hence the control of blood pressure
* blood clotting (
* formation of new blood vessels (
inflammationand swelling ( oedema)
Endothelial cells also control the passage of materials — and the transit of
white blood cells — 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 renal glomerulus and the
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, hypertensionor 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 L-arginine-stimulated nitric oxide synthesis.
Endothelium-derived relaxing factor( EDRF)
Robert F. Furchgott(1998 Nobel prize for discovery of EDRF)
*Endothelial progenitor cells
* - "Capillaries, non-fenestrated (EM, Low)"
* "Endothelium: Journal of Endothelial Research" [http://www.informaworld.com/smpp/title~content=t713617829]
* Molecular Biology of the CELL, 4th edition, Alberts et al., 2002
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