Diagram showing the location of endothelial cells

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. The cornea is the transparent front part of the Eye that covers the iris, Pupil, and Anterior chamber. The corneal endothelium is a monolayer of specialized flattened mitochondria-rich cells that lines the posterior surface of the Cornea and faces the Anterior The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called The blood vessels are part of the Circulatory system and function to transport Blood throughout the body Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells ��such as nutrients and oxygen—and transports Waste products A lumen (Lat lūmen, an opening or light (pl lumina is the inside space or lining of a tubular structure such as an artery or intestine Endothelial cells line the entire circulatory system, from the heart to the smallest capillary. This is an article about the rock music band "Circulatory System" The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic Capillaries are the smallest of a body's Blood vessels measuring 5-10 μm in diameter which connect Arterioles and Venules and enable the interchange These cells reduce friction of the flow of blood allowing the fluid to be pumped farther. Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e

Endothelial tissue is a specialized type of epithelium tissue (one of the four types of biological tissue in animals). In biology and medicine epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body Tissue is a cellular organizational level intermediate between cells and a complete organism More specifically, it is simple squamous epithelium. In Anatomy, squamous epithelium (from Latin squama, "scale" is an Epithelium characterised by its most superficial layer consisting

Endothelium of the interior surfaces of the heart chambers are called endocardium. The endocardium is the innermost layer of tissue that lines the chambers of the heart 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
• 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. Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles Blood pressure is also the title of a short story by Damon Runyan in Guys and Dolls and Other Stories Coagulation is a complex process by which Blood forms Clots It is an important part of Hemostasis (the cessation of blood loss from a damaged vessel whereby Thrombosis is the formation of a blood Clot ( Thrombus) inside a Blood vessel, obstructing the flow of Blood through the Circulatory Fibrinolysis is the process wherein a Fibrin clot, the product of Coagulation, is broken down Atherosclerosis is a Disease affecting arterial Blood vessels It is a chronic inflammatory response in the walls of arteries in large part due to the accumulation Angiogenesis is a physiological process involving the growth of new Blood vessels from pre-existing vessels Inflammation ( Latin, inflamatio, to set on fire is the complex biological response of vascular tissues to harmful stimuli such as Pathogens Oedema (or Edema in American English formerly known as dropsy or hydropsy, is the increase of Interstitial fluid in any organ &mdash swelling

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. A glomerulus is a Capillary tuft surrounded by Bowman's capsule in Nephrons of the vertebrate Kidney. The blood-brain barrier (BBB is a metabolic or cellular structure in the Central nervous system (CNS that restricts the passage of various chemical substances and microscopic

Pathology

Endothelial dysfunction, or the loss of proper endothelial function, is a hallmark for vascular diseases, and often leads to atherosclerosis. Endothelial dysfunction is a physiological Dysfunction of normal biochemical processes carried out by the Endothelium, the cells that line the inner surface of all Atherosclerosis is a Disease affecting arterial Blood vessels It is a chronic inflammatory response in the walls of arteries in large part due to the accumulation This is very common in patients with diabetes mellitus, hypertension or other chronic pathophysiological conditions. Diabetes mellitus (ˌdaɪəˈbiːtiːz or /ˌdaɪəˈbiːtəs/ /məˈlaɪtəs/ or /ˈmɛlətəs/ often referred to simply as diabetes ( Ancient Greek: grc Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the Blood pressure is chronically elevated 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. Nitric oxide or nitrogen monoxide is a Chemical compound with Chemical formula N[[Oxygen O]] Asymmetric dimethylarginine (ADMA is a naturally occurring chemical found in Blood plasma. Arginine (abbreviated as Arg or R) is an α- Amino acid. The L-form is one of the 20 most common natural amino acids Nitric oxide synthases ((NOSs are present among Eukaryotic enzymes as dimeric calmodulin-dependent or calmodulin-containing Cytochrome p450 -like Hemoprotein that

See also

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

External links

• endothelium at eMedicine Dictionary
• Organology at UC Davis Circulatory/vessels/capillaries1/capillaries3 - "Capillaries, non-fenestrated (EM, Low)"
• Histology at BU 21402ooa
• Endothelium: Journal of Endothelial Research [1]

References

• Molecular Biology of the CELL, 4th edition, Alberts et al. This article is about the biological functions of Nitric oxide. This article is about the biological functions of Nitric oxide. Robert Francis Furchgott (born June 4, 1916 in Charleston, South Carolina) is a Nobel Prize -winning American Biochemist In Biology, caveolae ( Latin for little caves) are small (50&ndash100 Nanometer) invaginations of the Plasma membrane in many vertebrate In Physiology, Weibel-Palade bodies are Organelles in the Endothelial cells the cells which make up the Endothelium, the exceedingly thin cell Endothelial microparticles are small vesicles that are released from endothelial cells and can be found circulating in the Blood. Endothelial progenitor cells are Bone marrow -derived cells that circulate in the blood and have the ability to differentiate into Endothelial cells, the cells that The endocardium is the innermost layer of tissue that lines the chambers of the heart The tunica intima (or just intima) is the innermost layer of an Artery or Vein. Susac's syndrome ( Retinocochleocerebral Vasculopathy) is a Microangiopathy characterized by Encephalopathy, branch Retinal artery occlusions eMedicine is an online clinical medical knowledge base that was founded in 1996 by Scott Plantz and Richard Lavely two medical doctors The University of California Davis, commonly known as UC Davis, or just UCD, is a public coeducational university located in the city of Davis, For similarly-named academic institutions see Education in Boston MA. , 2002