Molecular Classification
Other
Other Names
biliary duct, biliary tree (system of all ducts), ductus biliaris (Latin), common bile duct, intrahepatic bile duct, extrahepatic bile duct, hepatic duct, cystic duct
Disease Roles
Cancer (notably cholangiocarcinoma)Inflammation (cholangitis)Infection (primary sclerosing cholangitis, other cholangiopathies)

Bile duct Overview

The **bile duct** system comprises a branching network of tubes that transport bile from the liver and gallbladder to the duodenum (small intestine)[1][3][5][9]. The network is collectively termed the **biliary tree** and includes intrahepatic ducts (within the liver) and extrahepatic ducts (outside the liver), such as the right and left hepatic ducts, common hepatic duct, cystic duct, and common bile duct. The main biological function is to channel bile—a digestive fluid produced by the liver and stored in the gallbladder—that is essential for digesting fats and absorbing fat-soluble vitamins[1][3][5][9]. Diseases involving the bile ducts, such as cholangiocarcinoma (bile duct cancer), cholangitis (duct inflammation), obstruction, and congenital defects, are significant causes of hepatobiliary morbidity. The bile ducts themselves are not receptors, enzymes, or molecular targets, but rather anatomical structures lined by cholangiocytes (specialized epithelial cells)[7]. Emerging cancer therapies may target molecular alterations in the epithelial cells lining the ducts in diseases like cholangiocarcinoma, but not the duct as a molecular entity[2][4][6].

Mechanism of Action

Biological Functions

Bile transport
Fat digestion
Elimination of waste products
Homeostasis of bile acids

Disease Associations

Cancer (notably cholangiocarcinoma)
Inflammation (cholangitis)
Infection (primary sclerosing cholangitis, other cholangiopathies)
Obstructive disorders (gallstones, bile duct strictures)
Other (biliary atresia, congenital disorders)

Safety Considerations

  • Bile duct injury (iatrogenic during surgery)
  • Cholangitis (potential for infection)
  • Biliary strictures or leakage

Associated Biomarkers

Biomarker
Alkaline phosphatase
Gamma-glutamyl transferase (GGT)
Bilirubin
CA 19-9 (in cholangiocarcinoma)