In descriptions of the mechanism of gastric secretion, physiologists1 frequently speak of the nervous, the gastric, and the intestinal phases of secretion. These terms refer to the fact that a secretion of gastric juice in the stomach may be stimulated by impulses in the vagus nerves aroused reflexly by the sight, odor, or taste of food or by the introduction of food into the stomach or upper portions of the intestinal tract. The main outlines of the nervous phase of gastric secretion were delineated by the extensive studies of Pavlov and his pupils2 and have been confirmed and extended to man by observations made on ulcer patients treated by division of the vagus nerves to the stomach.3 These studies have indicated that the fasting continuous secretion of gastric juice in normal man is chiefly of nervous origin and that it is tremendously increased in duodenal ulcer patients.
DRAGSTEDT LR. The Physiology of the Gastric Antrum. AMA Arch Surg. 1957;75(4):552-557. doi:10.1001/archsurg.1957.01280160062007