Sunday, November 4, 2012
The epithelium is a membranous tissue which covers the external part of the body, in the form of skin, and lines the internal cavities of body organs and vessels. Since it is closely packed in one or two layers, it has no blood vessels. It is made up of three types of epithelial cells: cuboidal, squamous, and columnar. The epithelium has protective, secretory, sensory, absortive, and lubricating functions.