What are the three types of epithelial cells; what traits characterize each type? What distinguishes simple epithelial tissues from those that are pseudostratified or from those that are stratified?
Three types of epithelial cells exist: Squamous cells are thin and flat, cuboidal cells have a square shape in section and a polygonal shape when looking at the surface of a tissue, and columnar cells are much taller than they are wide. Simple epithelial tissues are only one cell thick and are named on the basis of their cell type: Simple squamous, simple cuboidal, and simple columnar epithelia are the three types of simple epithelial tissues. Psuedostratified epithelial tissues appear to have more than one layer of cells, but, actually, all the cells of such a tissue reach the underlying tissue just as the cells of a simple epithelial tissue do. Stratified epithelial tissues have two or more layers of cells. In stratified epithelial tissues, the outermost layer of cells determines the name of the tissue: Stratified squamous, stratified cuboidal, and stratified columnar epithelia are the three types of stratified epithelial tissues.
