BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The primary stimulus for secretion of gastrin is the presence of certain foodstuffs, especially peptides, certain amino acids and calcium, in the gastric lumen. Also, as yet unidentified compounds in coffee, wine and beer are potent stimulants for gastrin secretion.

Detailed explanation-2: -Gastrin is a hormone that is produced by ‘G’ cells in the lining of the stomach and upper small intestine, and released into the blood circulation. During a meal, gastrin stimulates the stomach to release gastric acid (hydrochloric acid).

Detailed explanation-3: -Secretin is synthesized and secreted by S cells in the small intestine, and neurons in the brain. Secretin release is mainly stimulated by gastric acid delivered into the duodenal lumen. In addition, secretin is released by digested products of fat and protein.

Detailed explanation-4: -Gastric secretion is stimulated chiefly by three chemicals: acetylcholine (ACh), histamine, and gastrin. Below pH of 2, stomach acid inhibits the parietal cells and G cells; this is a negative feedback loop that winds down the gastric phase as the need for pepsin and HCl declines.