THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Gallbladder contractions are induced by the action of cholecystokinin (CCK), a peptide hormone released by the neuroendocrine cells of the small intestine, on the CCK-A receptors of the interstitial cells of Cajal.

Detailed explanation-2: -Cholecystokinin is secreted by cells of the upper small intestine. Its secretion is stimulated by the introduction of hydrochloric acid, amino acids, or fatty acids into the stomach or duodenum.

Detailed explanation-3: -In humans, physiologic properties of CCK include the ability to stimulate gallbladder contraction, increase pancreatic enzyme secretion, delay gastric emptying, potentiate insulin secretion, and regulate food intake (table 1).

Detailed explanation-4: -Cholecystokinin (CCK) is produced by discrete endocrine cells in the proximal small intestine and is released following the ingestion of food. CCK is the primary hormone responsible for gallbladder contraction and has potent effects on pancreatic secretion, gastric emptying, and satiety.