Stephen Lichter, age 9, of Omaha, Neb., for his question:

WHAT DOES THE GALLBLADDER DO?

Most of the body's bile, which is also called gall, is manufactured by the liver and is stored in the gallbladder before it is released into the intestines to aid in the disgestion of food.

The gallbladder is a small sac and usually contains about one fluid ounce of bile. Bile from the liver enters the gallbladder through a cystic duct, and leaves the same way. It then passes on down to the common duct, which joins another from the pancreas, and then into the duodenum, a part of the small intestine.

A hormone called cholecystokinin acts as a signal for the gallbladder to contract and empty its contents into the intestines. The hormone is produced when there is an abundance of gastric juices in the duodenum.