Final answer:
Gastrin is a hormone secreted by the stomach in response to protein presence, stimulating the production of hydrochloric acid which assists in protein digestion and is regulated by a negative feedback mechanism involving the hormone somatostatin.
Step-by-step explanation:
When discussing the process of digestion, particularly with regard to gastrin, it is essential to understand its role in the regulation of stomach acid which is pivotal for protein digestion. Gastrin is a hormone secreted by G cells in the stomach in response to the presence of proteins in the stomach contents. It stimulates the parietal cells of the stomach lining to release hydrochloric acid (HCl), which decreases the pH of the stomach, aiding in the effective breaking down of protein structures.
This acidic environment also leads to the conversion of pepsinogen to its active form, pepsin, which is crucial for protein digestion. Additionally, gastrin plays a part in the hormonal control of the digestive system. The release of gastrin is part of a negative feedback mechanism; when the stomach empties, the hormone somatostatin halts the release of acid.