Epithelium

[Sarah]

The superficial layer of cells lining the alimentary canal andall its appendages, all glands and their ducts, blood vessels andlymphatics, serous cavities, etc. It often includes the epidermis (i.e., keratin-producing epithelial cells), and it is sometimesrestricted to the alimentary canal, the glands and their appendages,-- the term endothelium being applied to the lining membrane of theblood vessels, lymphatics, and serous cavities.

[Tanya Shivari]

The thin tissue forming the outer layer of a bodys surface and lining the alimentary canal and other hollow structures.