Slide #DMS 032 [Esophagus, H&E] Stratified squamous epithelium that is non-keratinized appears on moist surfaces that are subject to some abrasion. This type covers internal surfaces and is kept moist by the presence of mucus or other fluids and thereby, lubricated. This slide is of esophagus. Give particular attention to changes in the character of the cells as you study the various strata proceeding from the basal layer toward the surface. The most superficial cells still contain visible, albeit, pyknotic nuclei and may retain some viability prior to their sloughing. The human vagina is also lined by this type of epithelium.
This low power view of the adluminal portion of the esophagus shows the lumen (Lu) of the tube and the stratified squamous surface epithelium.
At medium power, the surface epithelium lining the esophagus can be seen to be comprised of multiple layers of cells and is thus stratified. While the shapes of the cells varies within the epithelium, the apical-most surface layer is comprised of flattened, or squamous cells. This epithelium is thus described as a stratified, squamous epithelium. Since the surface epithelium is exposed to a moist environment, the outermost cells do not exhibit the extensive keratinization (cornification) seen in the skin, and nuclei may be seen in these still living squamous cells.