[The endothelium].

It is well known that the endothelial cells represent one of the most active and versatile elements in the human organism. In fact apart from being the lining of the vessel wall they exert both antithrombotic and prothrombotic functions. Endothelial cells regulate the vasomotor tone and also have a part in the different immunological and inflammatory process. All these functions are possible because the endothelial cells produce many receptors on their surface. This paper is a review of the latest data on different roles played and substances produced by endothelial cells.