A. D cells in the pancreas – Explanation
Gastrointestinal hormones
Below is a brief summary of the major hormones involved in food digestion:
| Location | Stimulus | Actions | |
| Gastrin | G cells in the antrum of the stomach | Distension of stomach, vogue nerves (mediated by gastrin-releasing peptide), luminal peptides/amino acids Inhibited by: low antral pH, somatostatin |
Increases HCL, pepsinogen, and IF secretion, increases gastric motility, trophic effect on gastric mucosa |
| CCK | I cells in upper small intestine | Partially digested proteins and triglycerides | Increases secretion of enzyme-rich fluid from pancreas, contraction of gallbladder, relaxation of sphincter of Oddi, decreases gastric emptying, induces satiety |
| Secretin | S cells in upper small intestine | Acidic chyme, fatty acids | Increases secretion of bicarbonate-rich fluid from pancreas and hepatic duct cells, decreases gastric acid secretion |
| VIP | Small intestine, pancreas | Neural | Stimulates secretion by pancreas and intestines, inhibits acid secretion |
| Somatostatin | D cells in the pancreas & stomach | Fat, bile salts, and glucose in the intestinal lumen | Decreases secretion of acid |
