Not all mammals have gallbladders. The rat, for example, does not have a specialised organ for the storage of bile.
The gallbladder is connected to the main bile duct through the gallbladder duct (cystic duct or, in Latin, ductus cysticus). The main biliary tract runs from the liver to the duodenum, and the cystic duct is effectively a "cul de sac", serving as entrance and exit to the gallbladder. The surface marking of the gallbladder is the intersection of the mid-clavicular line (MCL) and the transpyloric plane, or the tip of the ninth rib.
Vascularisation is by the cystic artery and vein, which run parallel to the cystic duct.
The gallbladder has an epithelial lining characterised by recesses (called Aschoff's recesses), which are pouches inside the lining. Under the epithelium there is a layer of connective tissue, followed by a muscular wall that contracts in response to cholecystokinin.
Up to 25% of all people have gallstones, composed of cholesterol, lecitin and bile acids. These can cause colicky shooting abdominal pain, usually in relation with the meal, as the gallbladder contracts and gallstones pass through the bile duct. Surgery (cholecystectomy) is the most common treatment for gallstones. It can be performed laparoscopically, and it is in fact one of the most common procedures done through the laparoscope.
People at an increased risk of cholelithiasis are people who are 5 F's:
