Sappikanavat

Sappikanavat are the ducts that form part of the biliary system, responsible for carrying bile from the liver to the small intestine. They include intrahepatic ducts, which operate within the liver, and the extrahepatic ducts that transport bile to the duodenum.

Within the liver, bile flows from hepatocytes into small canaliculi, which drain into progressively larger interlobular and then intrahepatic ducts. The left and right hepatic ducts collect bile from the respective lobes and merge to form the common hepatic duct. The cystic duct, which connects to the gallbladder, can join with the common hepatic duct to form the common bile duct. The common bile duct then passes to the duodenum and joins the pancreatic duct before opening at the major duodenal papilla, controlled by the sphincter of Oddi.

The primary function of the sappikanavat is to transport bile, a digestive fluid essential for emulsifying fats. Bile contains bile acids, cholesterol, phospholipids, bilirubin, and waste products. After meals, bile is released from the gallbladder and flows through the ducts into the duodenum; between meals, bile production continues but the flow is reduced or diverted.

Clinical relevance includes obstruction or inflammation of the ducts, which can cause cholestasis, jaundice, and abdominal pain. Common conditions affecting sappikanavat include choledocholithiasis (bile duct stones), cholangitis (infection of the ducts), and cholangiocarcinoma (bile duct cancer). Diagnosis often uses ultrasound, magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP). Congenital anomalies, such as biliary atresia, can affect duct development and bile drainage in early life.