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The epithelial layer of cells lining the heart and vessels of the circulatory system.



a tissue found in animals and man consisting of specialized cells that line the inner surfaces of blood and lymph vessels, as well as the cavities of the heart. The endothelium is formed from the mesenchyme. It consists of a single layer of closely packed flat cells, which are usually separated from underlying tissues by a basal membrane. The endothelium of lymph vessels has no basal membrane. The cytoplasm of endothelial cells of certain capillaries may have pores that account for the permeability of the capillary wall, as, for example, in the renal glomeruli.

The endothelium of the enlarged capillaries of the blood-forming organs and the endothelium present in the liver, adrenal cortex, and certain other organs has a great capacity for phagocytosis. The endothelial cells of these organs belong to the reticuloendothelial system.

References in periodicals archive ?
Considering the ability of LEL to recognize GlyNAc and poly-N-acetyllactosamine we suggest that some material associated with the endothelia of pineal vessels can have these oligosaccharides residues.
Despite the immaturity of the initial stages (PN 1 and 3--many undifferentiated cells among a few connective tissue) (Calvo & Boya, 1984) the endothelia of these vessels showed sugar residues capable to bind tomato lectin.
However we are hopeful that our results showing a material containing specific residues (poly-acetyllactosamine and Gly-NAc) in the endothelia of PG vessels (specially in the majority of pseudo-rosettes) during the development and in adults rats will benefit future studies about the physiology of this gland.