Endothelial cell

The endothelial cell is a flattened cell type that forms a sheet (the endothelium) lining a blood vessel.

Endothelial cells line the entire vascular system[?], from heart to the smallest capillary, and control the passage of materials - and the transit of white blood cells - into and out of the bloodstream. They repair and renew the lining of established blood vessels, and creat new blood vessels.