Encyclopedia of Health and Medicine

G
gallbladder A small, muscular pouch on the
underside of the LIVER that concentrates and stores
BILE. The gallbladder absorbs about 90 percent of
the water in the bile that arrives from the liver,
creating concentrated, potent bile. Fats and proteins
in the chyme (partly digested food) the STOM-
ACH sends to the DUODENUM trigger the duodenum
to release the digestive HORMONE cholecystokinin
(CCK). CCK stimulates the gallbladder to contract,
expelling bile into the duodenum to aid with
digestion. The most common health conditions
that affect the gallbladder are cholelithiasis (gallstones),
cholecystitis (INFLAMMATION of the gallbladder),
and biliary dyskinesia (inadequate
contraction of the gallbladder). CANCER of the gallbladder
occurs though is rare.
For further discussion of the gallbladder within
the context of gastrointestinal structure and function,
please see the overview section “The Gastrointestinal
System.”
See also CHOLECYSTECTOMY; DIGESTIVE HORMONES;
GALLBLADDER DISEASE.
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gallbladder disease Disorders and dysfunctions
of the GALLBLADDER. Gallbladder disease becomes
more common with increasing age. Though medical
treatments can help some people with gallbladder
disease, surgery to remove the gallbladder is the
most common treatment and permanently resolves
symptoms in about 90 percent of people who have
primary gallbladder disease. Tumors and CANCER of
the gallbladder occur, though are very rare.
INFLAMMATION of the BILE DUCTS and HEPATITIS also can
affect BILE production and gallbladder function.
Gallbladder disease can be acute or chronic.
Biliary dyskinesia Dysfunction of the gallbladder
prevents it from contracting to eject bile,
reducing or stopping the flow of bile from the gallbladder
to the DUODENUM (first segment of the
small intestine). Biliary dyskinesia may occur as a
result of injury to the nerves that supply the gallbladder,
as a consequence of metabolic disorders
affecting LIVER function, or for unknown reasons
(most common).
Cholelithiasis Commonly called gallstones,
cholelithiasis develops over years to decades in
most people. Gallstones can range in size from a
few millimeters to several centimeters. There can
be one to a few to dozens. About 80 percent of
gallstones contain mostly cholesterol; bile pigments
such as BILIRUBIN make up the remainder.
Many people have gallstones without symptoms.
Gallstones become a health concern when they
lodge in the bile ducts or when they cause irritation
and inflammation of the gallbladder’s
mucosal lining. In a variation of cholelithiasis,
called choledocholithiasis, the gallstones form in
the bile ducts.
Cholecystitis Inflammation or INFECTION of the
gallbladder most commonly occurs in conjunction
with gallstones that block the flow of bile out of
the gallbladder, though it can develop in biliary
dyskinesia when the bile in the gallbladder stagnates.
This stagnation irritates and inflames the
lining of the gallbladder. Cholecystitis that occurs
without gallstones is acalculus cholecystitis.
GALLBLADDER DISEASE AND WEIGHT LOSS
These weight-loss efforts increase the risk for
gallbladder disease:
• rapid weight loss (3 pounds a week or greater)
• BARIATRIC SURGERY (gastric banding, stapling,
bypass)
• weight loss cycling (cycles of loss and regaining
weight, especially large amounts)