Which structure is stimulated to contract by cholecystokinin?

Cholecystokinin (CCK) is a peptide hormone that plays a crucial role in digestion, particularly in the digestion of fats and proteins. When food enters the small intestine, especially fats, CCK is released by the enteroendocrine cells in the duodenum. One of its primary functions is to stimulate the contraction of the gallbladder.

When CCK is secreted, it signals the gallbladder to contract and release bile into the duodenum. Bile is essential for the emulsification and digestion of fats, enabling more effective absorption of fatty acids and fat-soluble vitamins. The action of CCK on the gallbladder is a vital part of the digestive process following the intake of a meal rich in lipids.

Other structures in the body, such as the liver, pancreas, and stomach, do respond to CCK but in different ways. The pancreas, for example, is stimulated to secrete digestive enzymes, while the stomach's activity may decrease during the dosing of CCK. However, the direct effect of CCK and its primary purpose is to induce gallbladder contraction for bile release.