bile ducts

Bile ducts

Tubes that carry bile, a thick yellowish-green fluid that is made by the liver, stored in the gallbladder, and helps the body digest fats.

Mentioned in: Liver Transplantation, Percutaneous Transhepatic Cholangiography

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bile [bīl]

a clear yellow or orange fluid produced by the liver. It is concentrated and stored in the gallbladder, and is poured into the small intestine via the bile ducts when needed for digestion. Bile helps in alkalinizing the intestinal contents and plays a role in the emulsification, absorption, and digestion of fat; its chief constituents are conjugated bile salts, cholesterol, phospholipid, bilirubin, and electrolytes. The bile salts emulsify fats by breaking up large fat globules into smaller ones so that they can be acted on by the fat-splitting enzymes of the intestine and pancreas. A healthy liver produces bile according to the body's needs and does not require stimulation by drugs. Infection or disease of the liver, inflammation of the gallbladder, or the presence of gallstones can interfere with the flow of bile.

bile acids steroid acids derived from cholesterol; classified as primary, those synthesized in the liver, e.g., cholic and chenodeoxycholic acids, or secondary, those produced from primary bile acids by intestinal bacteria and returned to the liver by enterohepatic circulation, e.g., deoxycholic and lithocholic acids.

bile ducts the canals or passageways that conduct bile. There are three bile ducts: the hepatic duct drains bile from the liver; the cystic duct is an extension of the gallbladder and conveys bile from the gallbladder. These two ducts may be thought of as branches that drain into the “trunk,” or common bile duct. The common bile duct passes through the wall of the small intestine at the duodenum and joins with the pancreatic duct to form the hepatopancreatic ampulla, or ampulla of Vater. At the opening into the small intestine there is a sphincter that automatically controls the flow of bile into the intestine.

The bile ducts may become obstructed by gallstones, benign or malignant tumors, or a severe local infection. Various disorders of the gallbladder or bile ducts are often diagnosed by ultrasonography, radionuclide imaging, and x-ray examination of the gallbladder and bile ducts using a special contrast medium so that these hollow structures can be clearly outlined on the x-ray film.