Mucus is the major organic secretion of the gut produced by epithelia throughout the gastrointestinal (GI) tract. It is apparent as a viscous secretion slopping over the mucosal surfaces. In histological sections, the presecreted mucus endows the gastroduodenal epithelia with its characteristic neutral [periodic acid-Schiff (PAS) stain] and acidic (Alcian blue or high iron diamine) staining characteristics. Such observations do not, however, indicate the true nature of the protective mucus barrier, which is a layer of water-insoluble gel firmly adherent to the epithelial surfaces and forming a continuous protective barrier between them and the gastric juice in the lumen. It should be emphasized that this adherent mucus layer exists as a stable gel phase that is physically quite distinct from the viscous sloppy soluble mucus mixed with the gastroduodenal luminal contents.
KeywordsMucus Secretion Duodenal Ulcer Patient Unstirred Layer Gastric Mucus Mucosal Protection
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