Please forward this error screen to 81. Further documentation is available here. This article is about epithelium in animal anatomy. There are three principal shapes of epithelial atlas of histology with functional and clinical correlations pdf: squamous, columnar, and cuboidal.
The three principal shapes associated with epithelial cells are—squamous, cuboidal and columnar. However, when taller simple columnar epithelial cells are viewed in cross section showing several nuclei appearing at different heights, they can be confused with stratified epithelia. In general, it is found where absorption and filtration occur. The thinness of the epithelial barrier facilitates these processes. In general, simple epithelial tissues are classified by the shape of their cells. Stratified epithelium differs from simple epithelium in that it is multilayered. It is therefore found where body linings have to withstand mechanical or chemical insult such that layers can be abraded and lost without exposing subepithelial layers.
Cells flatten as the layers become more apical, though in their most basal layers the cells can be squamous, cuboidal or columnar. This specialization makes the epithelium waterproof, so is found in the mammalian skin. The lining of the esophagus is an example of a non-keratinized or “moist” stratified epithelium. In this case, the most apical layers of cells are filled with keratin, but they still retain their nuclei. Transitional epithelia are found in tissues that stretch and it can appear to be stratified cuboidal when the tissue is not stretched or stratified squamous when the organ is distended and the tissue stretches. The basic cell types are squamous, cuboidal, and columnar classed by their shape.