The tube system that carries bile from the liver and gallbladder to the duodenum, where it emulsifies dietary fat for digestion. The hepatic ducts from the liver join the cystic duct from the gallbladder to form the common bile duct, which delivers bile precisely when fatty food arrives. Blockage, most often by gallstones, backs bile up into the liver causing jaundice, pale stools, and the severe pain of biliary colic, while depriving the gut of the bile needed to absorb fats and fat-soluble vitamins. Surgeons navigate this anatomy carefully during gallbladder removal, since injuring the duct is a serious complication. The system’s elegant timing, storing bile between meals and releasing it on demand, shows digestion’s precise coordination.