Gallbladder

The gallbladder is a small, pear-shaped sac that stores and concentrates bile made by the liver, then releases it into the intestine to help digest fats. Though not essential for survival, it makes fat digestion more efficient by delivering a concentrated bile bolus right when a meal arrives.

Structure and Location

The gallbladder measures roughly 7 to 10 cm long and about 4 cm wide and typically holds 30 to 50 mL of bile. It rests in a shallow fossa on the undersurface of the liver (around liver segments IV and V) in the right upper quadrant of the abdomen. It has three main parts: the rounded fundus at the front, the central body, and the tapering neck, which narrows into the cystic duct. The cystic duct joins the common hepatic duct to form the common bile duct, the channel that carries bile to the duodenum.

Function

Between meals, bile produced continuously by the liver is diverted into the gallbladder, where the lining reabsorbs water to concentrate it severalfold. When fatty food enters the small intestine, the gut hormone cholecystokinin (CCK) signals the gallbladder to contract, squeezing concentrated bile through the cystic and common bile ducts into the duodenum. Bile salts then emulsify fats, breaking large fat globules into tiny droplets so that enzymes can digest them and the body can absorb fats and fat-soluble vitamins.

Clinical Relevance

The most common problem is gallstones (cholelithiasis), hardened deposits that form when bile components fall out of balance. A stone lodged in the cystic duct can block outflow and trigger painful inflammation called cholecystitis, while a stone in the common bile duct can obstruct bile flow and cause jaundice or pancreatitis. Symptomatic gallstone disease is often treated by surgically removing the gallbladder (cholecystectomy); the liver then delivers bile directly to the intestine. This page is educational and not medical advice.