What is the functional ROLE and PATTERN of cells of stratified squamous epithelial tissue?
Answers
Answer:
Stratified squamous epithelia are found in nearly every organ system where the body comes into close contact with the outside environment – from the skin to the respiratory, digestive, excretory and reproductive systems. They also protect the body from desiccation and water loss.
Explanation:
Answer:
Stratified squamous epithelium is limited to the esophagus in the human foregut. It does not occur in the stomach. This is not universal to all species; ruminating animals have squamous epithelium in the proximal stomach.
The normal stratified squamous epithelium of the esophagus can be reliably differentiated from columnar epithelium at gross examination of specimens (Figs. 4.3 and 4.4) and endoscopy (Fig. 4.5). Histologically, it has multiple layers of epithelial cells with a flat surface and broad rete pegs in its deep aspect (Fig. 4.6). The rete pegs are separated by short papillae that give the deep aspect of the epithelium an undulating appearance.
Explanation:
Stratified squamous epithelium
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Thickens and matures under influence of estrogen [peak levels at mid-cycle (day 15)]
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Estrogen gradually diminishes after day 15 and progesterone predominates; both hormones diminish approaching end of cycle
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Healthy, mature cervicovaginal stratified squamous epithelium in women of reproductive age has 3 main zones
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Basal zone (consisting of least mature, basal cells)
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Mid zone (consisting of parabasal cells and intermediate cells)
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Superficial zone (consisting of superficial cells)
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Due to lower estrogen levels during menopause, squamous epithelium is atrophic, maturing up to lower mid zone (i.e., predominantly parabasal cells)
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Progesterone permits squamous epithelial maturation to upper mid zone, thickening intermediate cell layers
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Proliferation &/or maturation of cervicovaginal squamous epithelium may also occur secondary to chronic irritation, inflammation, or infection and may produce hyperkeratosis &/or parakeratosis regardless of patient age