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-layer 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.
