Changes

On slide 131, Esophagus (H&E) identify the noncornified/nonkeratinized, stratified squamous epithelium. Note the flattened, nucleated surface cells, the “middle zone” of the polyhedral shaped cells, and the basal layer of the polyhedral shaped cells, and the basal layer of columnar cells which rests on the basement membrane. Characteristically, the lower surface of the epithelium is undulated.

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On slide 4, Thin skin (H&E) and Slide 46, Thick skin (H&E), study the representative types of cornified/keratinized, stratified squamous epithelium. Note the characteristics of the cells at the various levels. The surface layer of cells, represented by the stratum corneum of the epidermis, lacks nuclei and keratin proteins have replaced the cytoplasm. The surface cells of the skin are constantly desquamated. They are replenished by mitotic divisions occurring in the basal layer of epithelial cells. Note how much thicker the stratum corneum is for thick skin than for thin skin.

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On slide 111, Epiglottis (H&E), look in the connective tissue underlying the surface epithelium for ducts of glands lined with stratified cuboidal or stratified columnar epithelium. The surface epithelium of the epiglottis is an intermediate type where a change is being made from stratified squamous to pseudostratified columnar epithelium (some of the surface cells are torn off).

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