<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Epithelium (epi - + thele + - ium) is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue . Epithelial tissues line the cavities and surfaces of blood vessels and organs throughout the body . </P> <P> There are three principal shapes of epithelial cell: squamous, columnar, and cuboidal . These can be arranged in a single layer of cells as simple epithelium, either squamous, columnar, cuboidal, pseudo-stratified columnar or in layers of two or more cells deep as stratified (layered), either squamous, columnar or cuboidal . All glands are made up of epithelial cells . Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport, and sensing . </P>

Where are epithelial tissues located in the body