<prompt> Apical membrane of parietal cells contains which ion channels-Na K ATPaseH K ATPaseNa K 2Cl- transporterNa - Ca2 cotransporter  <response>: Ans. is b i.e., H K ATPase o The H are produced inside the parietal cell through the reaction of metabolic CO., with water. The reaction is catalyzed by carbonic anhydrase. H is secreted by proton pump H KATPase into the gastric lumen in exchange with a K ion and the HCG, is transported out of the parietal cells at the basolateral membrane by HCO3 - Cl- antiport into the interstitial fluid and from there into the blood. This HCO3- increases the blood pH. Hence after a meal, there is a rise in blood pH which is called the post-prandial alkaline tide.o The Cl that enter the parietal cell in exchange for HCO3 are secreted into the lumen. So, inside the gastric lumen secreted H and Cl- from hydrochloric acid HC1. 