Endothelium

[Sarah]

The thin epithelium lining the blood vessels, lymphatics, andserous cavities. See Epithelium.

[Merna]

the thin layer of cells that cover the inside walls of the blood vessels, heart and some other body parts)

[Tina]

The tissue which forms a single layer of cells lining various organs and cavities of the body, especially the blood vessels, heart, and lymphatic vessels. It is formed from the embryonic mesoderm.