The gallbladder stores bile formed within the liver, releasing it for fat digestion.
Bile travels through the intrahepatic ducts into the paired hepatic ducts; these merge into the common hepatic duct. Bile is then diverted via the cystic duct to the gallbladder for storage.
When food is ingested and travels through the stomach to the duodenum, a hormone is released (cholecystokinin) which stimulates the gallbladder to contract and the sphincter of Oddi to relax. This allows bile to flow through the cystic duct and the common bile duct into the duodenum.
The most common pathology in the extrahepatic biliary system is bile (gall) stones (concretions of bile salts, cholesterol, and minerals) which can block ducts, causing inflammation, pain, and jaundice.