gallstones are stones that form in the gall (bile). bile is a watery liquid made by the cells of the liver that is important for digesting food in the intestine particularly fat. liver cells secrete the bile they make into small canals within the liver. the bile flows through the canals and into larger collecting ducts within the liver (the intrahepatic bile ducts). the bile then flows within the intrahepatic bile ducts out of the liver and into the extrahepatic bile ducts -- first into the hepatic bile ducts then into the common hepatic duct and finally into the common bile duct. from the common bile duct there are two different directions that bile can flow. the first direction is on down the common bile duct and into the intestine where the bile mixes with food and promotes digestion of food. the second direction is into the cystic duct and from there into the gallbladder (often misspelled as gall bladder). once in the gallbladder bile is concentrated by the removal (absorption) of water. during a meal the muscle that makes up the wall of the gallbladder contracts and squeezes the concentrated bile in the gallbladder back through the cystic duct into the common duct and then into the intestine. (concentrated bile is much more effective for digestion than the un-concentrated bile that goes from the liver straight into the intestine). the timing of gallbladder contraction -- during a meal -- allows the concentrated bile from the gallbladder to mix with food. gallstones usually form in the gallbladder; however they also may form anywhere there is bile; in the intrahepatic hepatic common bile and cystic ducts. gallstones also may move about within bile for example from the gallbladder into the cystic or common duct.
what are gallstones?