The gallbladder is a pear-shaped sac that is attached to the posterior surface of the right lobe of liver. The gallbladder is divided into the fundus, body and neck. The portion that joins the neck is referred to as the infundibulum.
The main function of the gallbladder is to store and release bile into the duodenum. The release of bile is stimulated by the presence of dietary fats in the small intestine, where it acts as a surfactant to emulsify and digest lipids from the food.
The wall of the gallbladder is composed of three layers - mucosa, muscularis and serosa. There is no muscularis mucosae or submucosa. The mucosa is made up of branching folds lined by a single layer of columnar cells having a pale cytoplasm. The lamina propria encompasses loose connective tissue, blood vessels, nerves and sparse plasma cells. The muscularis is made up of randomly distributed smooth muscle fibers.