The above posts are right on with their comments on the function of the gallbladder. One thing that I might add is that in some extreme cases the gallbladder can be removed and people can go on and live a pretty normal life.
The gall bladder is attached to the liver. It is a small organ and acts as a reservoir to store bile. Bile is a green-yellow-brown substance that is capable of emulsifying fat from the diet. Emulsification is important as it breaks up large fat globules into smaller ones, much in the way dishwashing liquid breaks up grease in a frying pan. By emulsifying the fat we eat, the lipases(enzymes that digest fats and lipids) have smaller molecules to act on, thus, emulsification is an important step before digestion of fat can proceed. The liver is where bile is synthesized and the gall bladder is the structure where that bile is stored until needed. During digestion, the bile duct, which connects the gall bladder to the small intestine, releases bile into the small intestine. This is where the digestion of fats and lipids occurs.
Gallbladder (or cholecyst) is a temporary reservoir of bile, that is a yellowish brown fluid, produced by the liver. It is located in gallbladder fossa, beneath the liver. Gallbladder is specific to vertebrates. Gallbladder joins the liver, from where it receives the bile. Gallbladder joins the duodenum, where it discharges the bile, that emulsifies the fats in the food.
When we eat fatty foods, the gallbladder contracts and pour it's contents into the duodenum (if it is not irritated). Bile also contains substances that are toxic to liver, but stimulate the function of intestine.
Gallbladder has a pear shape. It has an average length of 8-10 cm and a volume of about 40 -50 cm ³. The gallbladder has a gray-green color. It is located on the visceral region of the liver, in the gallbladder fossa.
Lithiasis (gallstones) may be located in the gallbladder. Gallstones are composed of cholesterol and other constituents that are found in bile. Their size may be smaller than a grain of wheat or larger than a golf ball. The vast majority of these gallstones does not raise problems, but if they lock an excretory canal, urgent treatment is required.
Gall bladder is an organ found in the bodies of all animals with backbone that is used to store bile, which is a fluid secreted by lever. In humans the gall bladder of humans is pear shaped sac capable of holding about 45 millilitres of bile at a time. It is located on the underside of right portion of liver. During digestion bile flows from gall bladder and the liver, through the hepatic duct, to the duodenum, the first section of intestine The bile helps in digestion and absorption fatty foods. It also rids the body of certain waste products.
Between the meals the liver continues to produce bile which flows, through common bile duct, into the gall bladder, where it is concentrated and stored until needed for digestion.
The basic function of the gallbladder is to store bile that is produced in the liver before the bile is secreted into the intestines (bile is used to help your body digest fats). The most common problems associated with gall bladders include: inflammation of the gall bladder and bile ducts, muscular spasms and/or poor contraction of the gall bladder wall, formation of stones in the gall bladder and/or bile ducts, and obstruction to the free flow of bile. Depending on the severity of the gallbladder disease, a physician may recommend the removal of the gallbladder in a procedure called cholecystectomy.