six different types of epithelia
1) simple - single cell layer. Typically found where absorption, secretion, and filtration occur and a thin barrier is desired
2) stratified - two or more cell layers stacked on top of each other, are common in high-abrasion areas where protection is important, such as skin surface and lining of mouth
3) squamous - flattened and scalelike. Flat oval nucleus.
4) cuboidal - boxlike, approx as tall as they are wide. Nucleus is circular
5) columnar - tall and column shaped. Nucleus is oblong and toward bottom.
6) pseudostratified - cells varies in height, gives false impression that several layers are present