Epithelium acid resistance

An integrated model of acid resistance of the gastric epithelium, where the surface cell provides neutralization and generally a proton impermeable barrier. The parietal cell extrudes bicarbonate into the serosal side to supply this anion to the surface cell, and acid also appears to stimulate surface cell bicarbonate secretion. 

Because there is no resistant cyst, transmission from host to host must be direct. The inflammatory response in trichomoniasis is the major pathology associated with this organism however, the mechanisms of induction are not known. It is likely that mechanical irritation resulting from contact between the parasite and vaginal epithelium is a major cause of this response but the organism produces high concentrations of acidic end-products and poly amines, both of which would also irritate local tissues. 

Resistance to acid may therefore depend more on the ability of the esophageal epithelium to neutralize an add load than on restriction of entry of acid between the cells. Neutralization of acid occurs at the surface due to net HCOf secretion and also diffusion across the paracellular pathway, because... 

Barnes GT, La Mer VK. The evaporation resistances of monolayers of long-chain acids and alcohols and their mixtures. In La Mer VK, ed. Retardation of Evaporation by Monolayers Transport Processes. New York Academic Press, 1962 9-33. Ikeda K, Sasaki T, Shimura S, Satoh M, Isihara H, Sasaki H, Takishima T, Saitoh Y, Nishiyama A. Effect of surfactant on bioelectric properties of canine tracheal epithelium. Respir Physiol 1990 81 41-49. 

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