Gastric acid is secreted by the parietal cells in gastric mucosa. The basolateral membranes of these cells contain receptors for the three main stimulants of acid secretion, namely gastrin (from antral G cells), histamine (from enterochromaffin-like cells) and acetylcholine (from vagal efferents). The action
Fig. 31.1 Factors involved in maintaining acid balance
Prostaglandins Mucus Bicarbonate Mucosal blood flow of all these is to stimulate the gastric acid (proton) pump, which is the final common pathway for acid secretion. The pump is an H+/K+ ATPase, and when stimulated it translocates from cytoplasmic vesicles to the secretory canaliculus of the parietal cell and uses energy, derived from hydrolysis of ATP, to transport H+ out of parietal cells in exchange for K+. Hydrogen ions combine with chloride ions to form HC1, which is secreted into the gastric lumen.
On average, patients with duodenal ulcer produce about twice as much HC1 as normal subjects, but there is much overlap, and about half the patients with duodenal ulcer have acid outputs in the normal range. Patients with gastric ulcer produce normal or reduced amounts of acid.
Was this article helpful?
Do You Suffer From ASTHMA Chronic asthma is a paralyzing, suffocating and socially isolating condition that can cause anxiety that can trigger even more attacks. Before you know it you are caught in a vicious cycle Put an end to the dependence on inhalers, buying expensive prescription drugs and avoidance of allergenic situations and animals. Get control of your life again and Deal With Asthma Naturally