The gallbladder is an organ that lies inside the abdomen just under the liver. If you put your hand just under your right ribs at the front, this is roughly where your gallbladder is. Not surprisingly, this is where you get your pain if you get an inflamed gall bladder - a condition called cholecystitis.

A normal gallbladder is usually a floppy sack, often pinky green in colour, that is about 10 cm long and 2 or 3 cm across. Its job in normal life is to store bile that is made by the liver, and to discharge it into the bowel when you eat.

The bile contains several things. It contains the bile pigments which give bile its green colour. These bile pigments are in fact breakdown products of the blood and are therefore waste from the liver. However the bile also contains useful chemicals such as the bile salts.The bile salts are made by the liver and are essential to be able to absorb fat.

When you eat a meal, particularly if it is high in fat content, a chemical is released from the stomach called cholecystokinin (CCK). This causes the gallbladder to contract, forcing the bile through the cystic duct - a tube connecting the gallbladder with a larger tube called the common bile duct. The common bile duct is a tube connecting the liver with the duodenum - the part of the small intestine straight after the stomach.

The gallbladder is not essential, and therefore if it becomes inflamed - usually due to gallstones - it can be removed without causing any long-lasting problems.

If the gallbladder is removed, nowadays it is almost always removed using keyhole surgery - an operation called laparoscopic cholecystectomy.