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 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 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:
* vasoconstriction and vasodilation, and hence the control of blood pressure
* 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 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.

ee also

*Endothelium-derived relaxing factor (EDRF)
*Robert F. Furchgott (1998 Nobel prize for discovery of EDRF)
*Weibel-Palade bodies
*Endothelial microparticles
*Endothelial progenitor cells
*Tunica intima
*Susac's syndrome

External links

* - "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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Look at other dictionaries:

  • Endothelium — Endothélium L endothélium vasculaire est la couche la plus interne des vaisseaux sanguins, celle en contact avec le sang. Sommaire 1 Structure 2 Fonction 3 Spécialisation de l endothélium …   Wikipédia en Français

  • endothélium — [ ɑ̃dɔteljɔm ] n. m. • 1878; de endo et rad. de épithélium ♦ Anat. Couche de cellules épithéliales qui tapisse l intérieur des parois du cœur et des vaisseaux. ● endothélium nom masculin Fine couche de cellules tapissant la face interne de la… …   Encyclopédie Universelle

  • Endothelium — En do*the li*um, n.; pl. {Endothelia}. [NL., fr. Gr. e ndon within + ? nipple.] (Anat.) The thin epithelium lining the blood vessels, lymphatics, and serous cavities. See {Epithelium}. [1913 Webster] …   The Collaborative International Dictionary of English

  • Endothelĭum — (griech.), s. Epithelium …   Meyers Großes Konversations-Lexikon

  • Endothelium — Endothelĭum (grch.), feine zarte Haut auf der Innenfläche der Blutgefäße und Körperhöhlen; endotheliāl, mit dem E. zusammenhängend, von ihm ausgehend; Endotheliōm, geschwulstartige Neubildung des E …   Kleines Konversations-Lexikon

  • Endothelium — vgl. Endothel …   Das Wörterbuch medizinischer Fachausdrücke

  • endothelium — [en΄dō thē′lē əm] n. pl. endothelia [en΄dō thē′lēə] [ModL < ENDO + (EPI)THELIUM] the layer of cells lining the inside of blood and lymph vessels, of the heart, and of some other closed cavities endothelial adj. endothelioid adj. endotheloid… …   English World dictionary

  • Endothélium — L endothélium vasculaire est la couche la plus interne des vaisseaux sanguins, celle en contact avec le sang. Sommaire 1 Structure 2 Fonction 3 Spécialisation de l endothélium …   Wikipédia en Français

  • endothelium — A layer of flat cells lining especially blood and lymphatic vessels and the heart. [endo + G. thele, nipple] e. of anterior chamber [TA] a single layer of large, squamous cells that covers the posterior …   Medical dictionary

  • endothelium — n. the single layer of cells that lines the heart, blood vessels, and lymphatic vessels. It is derived from embryonic mesoderm. The corneal endothelium is the innermost layer of the cornea. Compare: epithelium Derivatives: endothelial adj …   The new mediacal dictionary

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