Final answer:
Stomach distension stimulates acid secretion, while amino acids and peptides in the stomach also stimulate acid secretion. Gastrin and other GI hormones are involved in regulating gastric acid secretion.
Step-by-step explanation:
Stomach distension stimulates the vagus nerve, resulting in acid secretion. Amino acids and peptides in the stomach also stimulate acid secretion. When food enters the stomach, stretch receptors are activated, causing the release of acetylcholine that stimulates the secretion of gastric juice. Gastrin, a hormone released by enteroendocrine G cells, is also stimulated by partially digested proteins, caffeine, and rising pH. Gastrin then induces parietal cells to increase their production of HCl, creating an acidic environment for protein digestion. Hormonal controls, such as gastrin and other GI hormones, play a role in regulating gastric acid secretion.