Gall bladder

The gallbladder is a small pear shaped organ that lies in the upper right part of the abdomen just underneath the liver and close to the diaphragm and rib cage. It acts as a reservoir for bile which is a digestive juice made by the liver and excreted down the bile duct which is a narrow tube coming out of the liver. The gallbladder is connected to the bile duct by a tube called the cystic duct. Bile enters and leaves the gallbladder via this connecting tube. The bile duct runs down to the bowel where it enters the duodenum. The valve where the bile duct meets the duodenum is called the ampulla (ampulla of Vater) it is also known as the sphincter of Oddi.

When you have a meal the sight and smell of food causes a complex chain of events to start which control release of bile into the duodenum from the gallbladder and bile duct via the ampulla. Food, particularly fatty food, entering the gut is a further strong stimulus for release of bile, which continues to be released until food and digestive juices reach the next part of the bowel.

If you do not have a gallbladder (e.g. following surgery) it makes very little difference to this process since bile is stored in the bile duct instead of the gallbladder. A normal gallbladder holds only around 25-40ml of bile. An average person makes 500-800ml of bile per day.