Bicarbonate Secretion and the Alkaline Microclimate
The surface mucosa of the healthy stomach and duodenum is continually exposed to a corrosive mixture of hydrochloric acid, pepsin, transient reflux of bile (exposing the stomach to the detergent effects of bile salts), food with varied consistency and temperature, microorganisms, and in some instances alcohol and drugs. In the duodenum, acid emptying from the stomach is rapidly neutralized, but pH values of ∼2 may still occur in the proximal duodenum for variable lengths of time. Clearly, these aggressive damaging luminal factors, along with ingested agents such as nonsteroidal anti-inflammatory drugs (NSAID) and alcohol, must be balanced by defense and repair processes, if mucosal integrity is to be maintained.
KeywordsGastric Inhibitory Polypeptide Mucosal Blood Flow Bicarbonate Secretion Proximal Duodenum Gastroduodenal Mucosa
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