Stratified Squamous Epithelium
Stratified squamous - This epithelium is composed of many layers of cells. Cells adjacent to the basement membrane are usually cuboidal, higher layers are polyhedral & surface cells are always flattened, hence the name "squamous". In certain locations the surface cells have a significant intracellular accumulation of the protein keratin; these epithelia are called "keratinized", “cornified”, or "dry". Cellular maturation from base to the apex leads to loss of organelles & nuclei and so surface squamous cells are non-nucleated. In epithelia where keratin does not form, the nucleus is retained even in the most superficial cells; this is called "non-keratinized", “non-cornified” or "wet" type.