Endothelial Cells

Endothelial cells are cells that cover all blood vessels; the layer being called the endothelium. These cells reduce turbulence of the flow of blood allowing the fluid to be pumped farther.

Endothelial cells are involved in many aspects of vascular biology, including:

• Barrier function - the endothelium acts as a selective barrier between the vessel lumen and surrounding tissue, controlling the passage of materials and the transit of white blood cells into and out of the bloodstream. Excessive or prolonged increases in permeability of the endothelial monolayer, as in cases of chronic inflammation, may lead to tissue swelling.
• control of blood pressure
• Blood clotting
• Formation of new blood vessels

In some organs, there are highly differentiated endothelial cells to perform specialized 'filtering' functions.