The gallbladder (or cholecyst) is a pear-shaped organ
that stores about 50 mL of bile (or "gall") until the body needs it for digestion. The gallbladder is about 7-10cm
long in humans and is dark green in appearance due to its contents (bile), not its tissue. It is connected to the liver and the
duodenum by the bilary tract.
The gallbladder stores bile, which is released when food containing
fat enters the digestive tract, stimulating the secretion of cholecystokinin (CCK). The bile emulsifies fats and neutralizes
acids in partly digested food. After being stored in the gallbladder, the bile becomes more concentrated than when it left
the liver, increasing its potency and intensifying its effect on fats
The gallbladder has an epithelial lining characterised by recesses
called Aschoff's recesses, which are pouches inside the lining. Under the epithelium there is a layer of connective tissue,
followed by a muscular wall that contracts in response to cholecystokinin, a peptide hormone secreted by the duodenum.
role in disease
Cholestasis is the blockage in the supply of bile into
the digestive tract. It can be "intrahepatic" (the obstruction is in the liver) or "extrahepatic" (outside the liver). It
can lead to jaundice, and is identified by the pr
Up to 25% of all people have gallstones (cholelithiasis),
composed of cholesterol, lecithinand bile acids. These can cause colicky shooting abdominal pain, usually in relation
with the meal, as the gallbladder contracts and gallstones pass through the bile duct. Surgery (cholecystectomy, removal of
the gallbladder) is the most common treatment for gallstones. It can be performed laproscopically, and it is in fact one of
the most common procedures done through the laparoscope.
People traditionally considered at an increased risk of cholelithiasis
are people who are 5 F's:
- fat (obesity)
- fair (Caucasian, but this is disputed by recent studies)
- forty (middle-aged)
- fertile (the risk is increased in pregnancy)
Acute or chronic inflammation of the gall bladder causes abdominal
pain 90% of cases of acute cholecystitis are caused by the presence of gallstones. The actual inflammation is due to secondary
infection with bacteria of an obstructed gallbladder, with the obstruction caused by the gallstones.
Not all mammals have gallbladders. The rat and horse, for example,
do not have a specialized organ for the storage of bile. The gallbladder is connected to the main bile duct through the gallbladder
duct (cystic duct or, in Latin, ductus cysticus). The main biliary tract runs from the liver to the duodenum, and
the cystic duct is effectively a "cul de sac", serving as entrance and exit to the gallbladder. The surface marking
of the gallbladder is the intersection of the mid-clavicular line (MCL) and the transpyloric plane, at the tip of the ninth
rib. The blood supply is by the cystic artery and vein, which run parallel to the cystic duct. The cystic artery is highly
variable, and this is of clinical relevance since it must be clipped and cut during a cholecystectomy
When gallstones obstruct the common bile duct, the patient
develops jaundiceand liver cell damage. It is a medical emergency, requiring endoscopic or surgical treatment.esence
of elevated bilirubin level that is mainly conjugated.
Gallbladder Polyps and Primary Scerlosing Cholangitis
Polyps (growths) are sometimes detected during diagnostic tests
for gallbladder disease. Small gallbladder polyps (up to 10 mm) pose little or no risk, but large ones (greater than 15 mm)
pose some risk for cancer, so the gallbladder should be removed. Patients with polyps 10 mm to 15 mm have a lower risk but
they should still discuss removal of their gallbladder with their physician. Of special note is a condition called primary
sclerosing cholangitis, which causes inflammation and scarring in the bile duct. It is associated with a lifetime risk of
7% to 12% for gallbladder cancer. The cause is unknown, although primary sclerosing cholangitis tends to strike younger men
who have ulcerative colitis. Polyps are often detected in this condition and have a very high likelihood of malignancy.