Flat epithelial tissues which are flat
and have more than one layer.
The Skin for a barrier. Your skin, for example, is a formidable barrier against many things. Skin is created when the basal cells in skin are dividing by the process of mitosis and, as division takes place, the cells get pushed upwards. As a result, the newer cells tend to stay near the bottom of the epithelial tissue, and the older cells get pushed upward and eventually are lost as they flake off. Cells flake off because by the time they reach the free surface of the tissue(top) they are dead. These dead cells form a covering of keratin, and because of that, skin is called a keratinized membrane. Due to the fact that the basement membrane is avascular. The nutrients and oxygen which keep cells alive must diffuse through the basement membrane and up into the cells of the epithelium. And because in the stratified epithelium the upper cells are often too far way to get enough oxygen and nutrients, so they die. -Though this is not always the case in stratified squamous epithelium. Although skin is an example of stratified squamous epithelial tissue that forms a keratinized membrane, there is other stratified squamous epithelial tissue whose surface cells are still alive. They are called Moist Stratified Squamous Epithelium because the surface cells are covered with mucus.
i.e Epithelial tissue in your mouth is an example of a Moist Stratified Squamous Epithelium. Though the surface cells are alive, they still are much less active then the cells below, because they are father away from the source of diffusing oxygen and nutrients.
The Body also has Stratified Cuboidal Epithelial Tissue and Stratified Columnar epithelial Tissue.
2. Stratified Transitional Epithelium
The Stratified Transitional Epithelium is a kind of tissue offers good protection (due to the fact that it is...