The endothelium is the layer of thin, flat cells that lines 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. In small blood vessels and capillaries, endothelial cells are often the only cell-type present. Endothelial cells are involved in many aspects of vascular biology, including: Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, and are sometimes called the building blocks of life. ... The arterial system The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... In anatomy, the lumen is the cavity or channel within a tube or tubular structure, such as the vascular lumen of a blood vessel, along which blood flows. ... A circulatory system (sometimes cardiovascular system) is an organ system that moves substances to and from cells; it can also help stabilize body temperature and pH (part of homeostasis). ... The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ in vertebrates that pumps blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods. ... Capillaries are the smallest of a bodys blood vessels, measuring 5-10 μm. ...

• vasoconstriction & vasodilation, and hence the control of blood pressure
• blood clotting (thrombosis & fibrinolysis)
• atherosclerosis
• formation of new blood vessels (angiogenesis)
• inflammation and swelling (edema)

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. The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Blood pressure is the pressure exerted by the blood on the walls of the blood vessels. ... The coagulation of blood is a complex process during which blood forms solid clots. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... Fibrinolysis is the process where a fibrin clot, the product of coagulation, is broken down. ... Angiogenesis is the physiological process involving the formation of new blood vessels from pre-existing vessels. ... Inflammation is the first response of the immune system to infection or irritation and may be referred to as the innate cascade. ... Edema (BE: oedema, formerly known as dropsy) is swelling of any organ or tissue due to accumulation of excess fluid. ... White blood cells (also called leukocytes or immune cells) are a component of blood. ... The glomerulus is a capillary bed found surrounded by the Bowmans capsule of the nephron in the vertebrate kidney. ... The blood-brain barrier is a physical barrier between the blood vessels in the central nervous system, and most parts of the central nervous system itself. ...

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. Endothelial dysfunction is a physiological dysfunction of normal biochemical processes carried out by endothelial cell, the cells that line the inner surface of all blood vessels, arteries and veins. ... For the disease characterised by excretion of large amounts of severely diluted urine, see diabetes insipidus. ... For other forms of hypertension see hypertension (disambiguation) Hypertension or high blood pressure is a medical condition wherein the blood pressure is chronically elevated. ...

See also

• Endothelium-derived relaxing factor (EDRF)
• Robert F. Furchgott (1998 Nobel prize for discovery of EDRF)
• Caveolae
• Weibel-Palade bodies
• Endothelial microparticles
• Endocardium

Endothelium-derived relaxing factor (EDRF) was the tentative name of what was later discovered to be nitric oxide (NO). ... Endothelium-derived relaxing factor (EDRF) was the tentative name of what was later discovered to be nitric oxide (NO). ... Robert F. Furchgott (born June 4, 1916 in Charleston, South Carolina) is a Nobel Prize-winning American chemist. ... In biology, caveolae (Latin for little caves) are small invaginations of the plasma membrane in many cell types, especially in endothelial cells. ... In physiology, Weibel-Palade bodies are organelles in the endothelium, the cells lining all blood vessels. ... Endothelial microparticles are small vesicles that are released from endothelial cells and can be found circulating in the blood. ... In the heart, the endocardium is the innermost layer of cells, embryologically and biologically similar to the endothelium that lines blood vessels. ...

External links

• Endothelium -- Journal of Endothelial Cell Research