Sappitiehyen

Sappitiehyen, or bile ducts, are a network of thin-walled tubes that convey bile from the liver and gallbladder to the duodenum. They include intrahepatic bile ducts within the liver and extrahepatic ducts outside it, such as the common hepatic duct, cystic duct, and common bile duct. Bile produced by hepatocytes drains into canaliculi, then into progressively larger ducts that converge into the left and right hepatic ducts and, together, form the common hepatic duct. The cystic duct from the gallbladder joins to create the common bile duct, which traverses to the duodenum via the hepatopancreatic ampulla and the major duodenal papilla, under control of the sphincter of Oddi.

The primary function of the sappitiehyen is to transport bile, a digestive fluid that contains bile acids, cholesterol, phospholipids, and bilirubin. Bile emulsifies fats and aids in their digestion and absorption. Flow through the ducts is regulated by hormonal and neural signals and can increase after a meal, aligning with digestive needs.

Clinical relevance is significant, as obstructions or injuries to the bile ducts can cause jaundice, cholestasis, or cholangitis. Common causes include gallstones, tumors, inflammation, or surgical injury. Diagnosis commonly involves ultrasound, magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP). Treatment may include stone extraction, biliary stenting, or surgical reconstruction.

Developmentally, sappitiehyen arise from the hepatic diverticulum in foregut endoderm. Anatomical variations can occur, including atypical ductal courses or duplications, which are important considerations in surgery and imaging. See also hepatobiliary system.