Anatomy and Physiology II Practice Test 2026 - Free Anatomy Practice Questions and Study Guide

Cholecystokinin (CCK) plays a crucial role in the digestive system primarily by stimulating the contraction of the gallbladder. When food—especially fats and proteins—enters the small intestine, CCK is released from the lining of the small intestine in response to these nutrients. The contraction of the gallbladder causes it to release bile into the duodenum, which is essential for emulsifying fats and aiding in their digestion and absorption.

Additionally, while CCK does have other functions such as inhibiting gastric secretion, stimulating the pancreas to produce digestive enzymes, and influencing appetite, its primary action linked to digestion is related to the gallbladder. This makes the stimulation of gallbladder contraction a key factor in the coordinated response necessary for digestive efficiency, particularly in the breakdown of dietary fats.