Gallenwege

The Gallenwege, or biliary tract, are the network of ducts that transport bile from the liver and gallbladder to the small intestine. They comprise intrahepatic ducts (including canaliculi and interlobular ducts) and the extrahepatic ducts: the left and right hepatic ducts, which join to form the common hepatic duct. The cystic duct from the gallbladder merges with the common hepatic duct to form the common bile duct, which typically travels to the second part of the duodenum and opens at the major duodenal papilla under the control of the sphincter of Oddi.

Bile produced by hepatocytes flows through these ducts to aid digestion, particularly fat emulsification. Between meals the gallbladder stores and concentrates bile; hormonal signals, especially cholecystokinin, trigger bile release into the intestine. Bile consists of bile acids, bilirubin, cholesterol, phospholipids, and electrolytes.

Clinical relevance includes obstruction of the biliary tract, most commonly by gallstones, which can cause jaundice, dark urine, pale stools, and abdominal pain. Other conditions include cholangitis (infection of the bile ducts), PSC (primary sclerosing cholangitis), and biliary strictures or tumors. Diagnosis typically involves ultrasound, magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP). Laboratory tests often show a cholestatic pattern with elevated alkaline phosphatase and bilirubin. Treatment depends on the cause and may involve stone extraction or stenting, biliary drainage, or cholecystectomy.

Embryology and anatomy notes: the bile ducts arise from the hepatic diverticulum and share close relationships with the pancreatic duct system; anatomical variants are common and relevant for surgery, particularly cholecystectomy.