RECENT ADVANCES IN THE PHYSIOLOGY OF GASTRIC ACID SECRETION

The classic scheme of gastric acid secretion which divided the digestive period into cephalic, gastric and antral phases has become obsolete in the last 10 years. These "phases" are now seen as concurrently acting mechanisms which depend upon one another to be fully efficient. About half of all gastrin released during a meal is dependent upon vagal stimulation of the antrum. Also, vagotomy desensitizes the acid-secreting parietal cells to the effect of all other types of stimuli.The number of parietal cells (parietal cell mass) varies greatly according to the gastric secretory activity of each individual. It is highest with duodenal ulcer and lowest with gastric ulcer.Parietal cell hyperplasia or atrophy can be induced experimentally, but the factors controlling the size of the parietal cell mass in man have not been studied.A scheme of acid secretion which incorporates recent advances is presented.