The bile duct is a tube and is part of the network called the biliary tree. It is also called the common bile duct (CBD). It is present in the gastrointestinal tract and is formed with the connection of the hepatic duct and the cystic duct in the gallbladder. The CBD along its path is connected to the pancreatic duct. The combination of these ducts is called the ampulla of Vater. The CBD is a tubular structure and it carries bile from the gallbladder to the duodenum (small intestine). As food enters the small intestine, bile enters the small intestine via the CBD in order to facilitate digestion. The end point of the CBD is called the sphincter of Oddi. Disorders of CBD include birth defects leading to obstruction, presence of gallbladder stones, inflammation, scarring, bile duct obstruction (See: Bile Duct Obstruction), and bile duct cancer. Since the liver and pancreas are closely connected by the CBD, in people with diabetes, a major cause for bile duct obstruction is diabetes. In fact, diabetes is also linked to bile duct cancer.