Final answer:
Somatostatin is the hormone that stops acid secretion in the stomach, acting as a negative feedback mechanism following the stimulation by gastrin.
Step-by-step explanation:
The hormone that stops acid secretion in the stomach is somatostatin. During the gastric phase, the hormone gastrin is secreted by G cells in response to the presence of proteins, thus stimulating the release of stomach acid, or hydrochloric acid (HCl). However, somatostatin is the hormone that inhibits the secretion of gastric acid once the stomach has been emptied.
It is important to note that while gastrin is responsible for signaling the secretion of gastric acid, somatostatin functions as a negative feedback mechanism, ensuring that excess stomach acid is not produced, which can be harmful to the stomach lining and overall digestion.