AskDefine | Define endothelium

Dictionary Definition

endothelium n : an epithelium of mesoblastic origin; a thin layer of flattened cells that lines the inside of some body cavities [also: endothelia (pl)]

User Contributed Dictionary



endothelium (plural endothelia)
  1. A thin layer of flat epithelial cells that lines the heart, serous cavities, lymph vessels, and blood vessels.

Derived terms

Extensive Definition

The endothelium is the thin layer of cells that line the interior surface of blood vessels, forming an interface between circulating blood in the 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 friction 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 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:
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 blood-brain barrier.


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 L-arginine-stimulated nitric oxide synthesis.

See also

External links


  • Molecular Biology of the CELL, 4th edition, Alberts et al., 2002
endothelium in Bulgarian: Ендотел
endothelium in Catalan: Endoteli
endothelium in German: Endothel
endothelium in Spanish: Endotelio
endothelium in Esperanto: Endotelio
endothelium in French: Endothélium
endothelium in Italian: Tessuto endoteliale
endothelium in Latin: Endothelium
endothelium in Dutch: Endotheel
endothelium in Japanese: 血管内皮
endothelium in Low German: Endothel
endothelium in Polish: Śródbłonek
endothelium in Portuguese: Endotélio
endothelium in Serbian: Ендотел
endothelium in Swedish: Endotel
endothelium in Vietnamese: Tế bào nội mô
endothelium in Chinese: 內皮細胞
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