Endothelium forms the inner lining of blood vessels and lymphatic ducts. It lines all the vessels and hence it is distributed throughout the body. It exhibits structural and functional heterogeneity and has multiple functions. It regulates angiogenesis and maintains a delicate balance between coagulation and fibrinolysis. It is not just a simple barrier between intra and extravascular compartments but it regulates exchange of solutes, water, regulates permeability, synthesizes, converts and metabolises many hormones/mediators. Endothelial cells release vasoconstrictors and vasodilators to regulate vascular tone and expresses adhesion molecules for the extravasation of leucocytes and lymphocytes in health and inflammation. The endothelium present in all the blood vessels exhibits wide variety of functions and therefore endothelial dysfunction results in widespread disease of the body. This review gives a gross view of the various functions of endothelium and a basic idea about its dysfunction.
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