What is the gallbladder?

Structure and Functions

The gallbladder is part of the digestive system. Bile originates in the liver then flows into the gallbladder through a system of ducts. Some bile flows directly into the small intestine, but the gallbladder collects and concentrates much of the bile. It then contracts and releases more bile into the small intestine as food is eaten. Bile helps break down the fats and neutralize the acids in the food. The organs and ducts that transport bile are collectively called the biliary system and include the gallbladder, liver, pancreas, stomach, small intestine, and the ducts connecting these organs.

Disorders and Diseases

Gallstones are a very common gallbladder problem. Two types of stones may form. Cholesterol stones are the most common type of gallstone, and they form when there is too much cholesterol in the bile. Pigment stones are less common, occurring only about 20 percent of the time; they are formed when there is too much bilirubin in the bile. Gallstones may be any size, ranging from stones that are tiny, like grains of sand, up to the size of a golf ball. When stones are small, they may form a type of “sludge” that affects the functioning of the gallbladder. If they are large, then they may move about and cause blockage of the ducts that drain the bile from the gallbladder into the digestive system, causing pain or a “gallbladder attack.” Stones may exit the gallbladder and block other areas of the digestive system, causing pain, infection, or organ damage. However, it is possible to have gallstones that cause no pain or problem at all.

Some risk factors for gallstones include being female (especially females who have been pregnant or have taken hormones), being overweight, losing weight quickly (such as with “crash” dieting), or having high blood cholesterol levels.

Common symptoms of gallstones include pain in the upper right abdomen (especially within thirty minutes after a fatty meal), nausea, vomiting, fever, indigestion, gas, constipation, diarrhea, or bloating. Stones blocking the common bile duct are likely to cause symptoms such as jaundice, dark urine, and rapid drop in blood pressure. Some relief may be found by following a low-fat diet, and some patients find relief through nontraditional methods, such as acupuncture or herbal medicine. More conventional treatments may involve dissolving the gallstones by various methods; however, once gallstones begin to form, they are very likely to return, so this option may not be a long-lasting one. Another possibility is to perform a therapeutic endoscopic retrograde cholangiopancreatography (ERCP), which allows stones to be removed or ducts to be opened. In complicated or recurring cases, the treatment for gallstones involves removing the gallbladder (cholecystectomy). Without the gallbladder, all bile flows directly from the
liver into the small intestine. In most people, gallbladder removal has almost no side effects; in a very small percentage (approximately 1 percent), bile traveling directly into the small intestine can cause diarrhea.

Untreated gallstones can become life-threatening due to infection or organ damage because of blockages, and complications including gangrene and perforation of the gallbladder can occur. People with diabetes are, for unknown reasons, more likely to have serious complications from gallstones.

Gallbladder cancer
is quite rare, with new cases of less than ten thousand per year in the United States. It is seen most often in people aged seventy and older and is more common in women than in men. The cause of gallbladder cancer is unknown, but risk factors include a history of gallstones, porcelain gallbladder (a rare condition where calcium lines the walls of the gallbladder), smoking, family history of gallbladder cancer, and obesity. There are usually no symptoms of gallbladder cancer; most cancers are found incidentally during surgery to remove gallstones. Surgery to remove the gallbladder, radiation therapy, and/or chemotherapy are all possible treatments for gallbladder cancer.

Perspective and Prospects

The gallbladder has been recognized throughout history as an important organ in the digestive process. It is one of the organs in the “four humors” system of medicine, which may have originated in Mesopotamia or Egypt but reached its height in the Greek system of medicine. In that system, the gallbladder was linked to the season of summer and the element of fire, and an overabundance of bile was thought to cause one to be bad-tempered or “choleric.” In traditional Chinese medicine, the gallbladder is thought to affect the quality and length of sleep.

Bibliography

Andrén-Sandberg, Åke. "Diagnosis and Management of Gallbladder Cancer." North American Journal of Medical Sciences 4, no. 7 (July, 2012): 293–99.

Clavien, Pierre-Alain, ed. Diseases of the Gallbladder and Bile Ducts: Diagnosis and Treatment. 2d ed. Wiley-Blackwell, 2006.

"Gallbadder Removal—Laparoscopic." MedlinePlus, August 1, 2011.

Kraus, J. The Etiology, Symptoms, and Treatment of Gall-Stones. BiblioLife, 2009.

Lack, Ernest E. Pathology of the Pancreas, Gallbladder, Extrahepatic Biliary Tract, and Ampullary Region. New York: Oxford University Press, 2001.

Mitchell, George. Learn About Your Liver and Gallbladder. Dupage Digital, 2008.

PM Medical Health. Twenty-first Century Ultimate Medical Guide to Gallbladder and Bile Duct Disorders: Authoritative Clinical Information for Physicians and Patients. Progressive Management, 2009.

Savitsky, Diane. "Gallstones." Health Library, September 30, 2012.

Thomas, Charles, and Clifton Fuller, eds. Biliary Tract and Gallbladder Cancer: Diagnosis and Therapy. Demos, 2008.

Thudichum, John Louis William. A Treatise on Gall-stones: Their Chemistry, Pathology, and Treatment. BiblioLife, 2009.