The bile ducts are those ductal structures that carry bile secreted by the liver to the duodenum. It generally includes two parts: intrahepatic and extrahepatic bile ducts. The intrahepatic biliary tract has bile ducts, left and right hepatic ducts; the extrahepatic biliary tract includes the common hepatic duct, common bile duct, cystic duct and gallbladder. If we think of the biliary system as a “river” that gradually converges and grows from small to large, the source is the numerous bile ducts located in the lobules of the liver. . The gallbladder is connected by the cystic duct, which has the functions of storage, concentration, contraction (bile discharge) and secretion, and plays the role of storing and regulating bile.