The biliary tract (or biliary tree) is the common anatomical term for the path by which bile is secreted by the liver then transported to the first part of the small intestine, also known as the duodenum. A structure common to most members of the mammal family, it is referred to as a tree because it begins with many small branches which end in the common bile duct, sometimes referred to as the trunk of the biliary tree. The duct, the branches of the hepatic artery, and the portal vein form the central axis of the portal triad. Bile flows in the direction opposite to that of the blood present in the other two channels.
Clinical significance 
The biliary tract can also serve as a reservoir for intestinal tract infections. Since the biliary tract is an internal organ, it has no somatic nerve supply, and colicky pain due to infection and inflammation of the biliary tract is not a somatic pain. Rather, pain may be caused by luminal distension, which causes stretching of the wall. This is the same mechanism that causes pain in bowel obstructions.
The path is as follows:
- Bile canaliculi >> Canals of Hering >> bile ductules (in portal tracts) >> intrahepatic bile ducts >> left and right hepatic ducts >>
- merge to form >> common hepatic duct >>
- exits liver and joins >> cystic duct (from gall bladder) >>
- forming >> common bile duct >> joins with >> pancreatic duct >>
- forming >> ampulla of Vater >> enters duodenum
An obstruction of the biliary tract can result in jaundice, a yellowing of the skin and whites of the eyes.
- Biliary tract at the US National Library of Medicine Medical Subject Headings (MeSH)
- "Dorlands Medical Dictionary:biliary tract".
- "Definition: biliary tract from Online Medical Dictionary".