Epithelial tissue types

Stratified squamous: A stratified squamous epithelium consists of squamous (flattened) epithelial cells arranged in layers upon a basal membrane. Although this epithelium is referred to as squamous, many cells within the layers may not be flattened; this is due to the convention of naming epithelia according to the cell type at the surface. In the deeper layers, the cells may be columnar or cuboidal. This type of epithelium is well suited to areas in the body subject to constant abrasion, as it is the thickest and layers can be sequentially sloughed off and replaced before the basement membrane is exposed. It allows passage of materials by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae. Location: Kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, and lymphatic vessels; lining of ventral body cavity (serosae). Simple Columnar: A simple columnar epithelium is a columnar epithelium that is uni-layered. In humans, a simple columnar epithelium lines most organs of the digestive tract including the stomach, small intestine, and large intestine. Simple ciliated columnar epithelia line the uterus. The main function of simple columnar epithelial cells is protection.

Simple cuboidal: Simple cuboidal cells are classified as simple since they consist of only a single layer of cells and are cube shaped. By lining the surface of various ducts of various glands and organs, simple cuboidal cells are able to provide a layer of protection from abrasion, foreign particles, invading bacteria and excessive water loss (due to its selective permeability) to the underlying tissue. In the kidney tubules, the cells aid in the absorption and transport of filtered substances. In the kidney tubules, the cells aid in the absorption and transportation of filtered substances. Simple cuboidal epithelium lines the surface of small excretory ducts in various organs and glands in the body, compose some of the