Epithelium

(EP-ih-THEE-lee-um) A thin layer of tissue that covers organs, glands, and other structures within the body.

The layer of cells forming the epidermis of the skin. These cells serve the general functions of protection, absorption, and secretion, and play a specialized role in moving substances through ducts, in the production of germ cells, and in the reception of stimuli. Their ability to regenerate is excellent; the epithelium may replace itself as frequently as every 24 hours.