The gallbladder is a pear-shaped sac located on the posterior surface of the liver that is around 7-10 cm long and 3 cm broad with a capacity of 30-50 ml. It has three parts - the body, fundus, and neck - and is attached to the liver by connective tissue. The cystic duct is around 3-4 cm long and connects the gallbladder neck to the bile duct, which is around 8 cm long and formed by the union of the cystic and common bile ducts. The gallbladder stores and concentrates bile and regulates pressure in the biliary system.