The bile duct is a tube that carries bile, a digestive fluid produced by the liver, to the small intestine. Bile helps in the digestion of fats and is essential for nutrient absorption. The bile duct system includes the common bile duct, which connects the liver and gallbladder to the small intestine. Bile is stored in the gallbladder until it is needed for digestion. When food enters the small intestine, the bile duct releases bile to aid in breaking down fats. Any blockage or inflammation in the bile duct can lead to digestive issues and may require medical attention.