Maksukanavat

Maksukanavat, or maksakanavat, are a network of ducts that transport bile produced by the liver to the digestive tract. They form part of the biliary system and are essential for fat digestion and waste elimination. The intrahepatic component consists of progressively larger ducts within the liver, beginning with bile canaliculi and biliary ductules that merge into left and right hepatic ducts.

The left and right hepatic ducts exit the liver and join to form the common hepatic duct. The cystic duct from the gallbladder may join the common hepatic duct to form the common bile duct, which delivers bile into the duodenum through the major duodenal papilla, regulated by the sphincter of Oddi. Bile ducts are lined by cholangiocytes and receive arterial and portal venous blood supply; they are accompanied by peribiliary glands and a surrounding connective tissue sheath.

Physiology and flow of bile are influenced by feeding and intestinal signals. Bile secretion includes bile acids, cholesterol, phospholipids, and bicarbonate, contributing to fat emulsification and digestion. Bile flow can be altered by hormonal and neural inputs, as well as by the enterohepatic circulation of bile acids.

Clinical relevance includes obstruction or injury to the biliary tree, which can cause cholestasis, jaundice, and abdominal pain. Common conditions affecting maksukanavat include gallstone obstruction of the common bile duct, cholangiocarcinoma, biliary atresia in infancy, and inflammatory diseases such as primary sclerosing cholangitis. Diagnostic tools include ultrasound and magnetic resonance cholangiopancreatography (MRCP), while treatment may involve endoscopic or surgical drainage and, in some cases, resection or bypass procedures.