What triggers the release of CCK leading to gallbladder contraction and pancreatic enzyme secretion?

• A. Fatty acids in the small intestine
• B. Glucose in the small intestine
• C. Amino acids in the stomach
• D. Alcohol in the stomach

Answer: (A)

Fatty acids in the chyme entering the small intestine stimulate I cells to release cholecystokinin (CCK). This hormone travels to the gallbladder, causing it to contract and push bile into the duodenum to help emulsify fats. At the same time, CCK acts on the pancreatic acinar cells to secrete digestive enzymes and relaxes the sphincter of Oddi so bile and pancreatic juice can flow into the intestine. So fats in the small intestine are the primary trigger for CCK-driven gallbladder contraction and pancreatic enzyme release. Glucose in the small intestine mainly activates other pathways (like GIP) rather than CCK. Amino acids in the stomach mainly stimulate gastrin for acid secretion, and alcohol in the stomach does not notably trigger CCK release.