- Category: Digestive system
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The gallbladder is a small storage organ located inferior and posterior to the liver. Though small in size, the gallbladder plays an important role in our digestion of food. The gallbladder holds bile produced in the liver until it is needed for digesting fatty foods in the duodenum of the small intestine. Bile in the gallbladder may crystallize and form gallstones, which can become painful and potentially life threatening.
Anatomy of the gallbladder
Hollow, muscular and pear-shaped, the gallbladder is a small organ – only about 3 inches in length and 1.5 inches in width at its widest point. The larger end of the gallbladder extends inferiorly and to the right while the tapered end points superiorly and medially. The tapered end of the gallbladder narrows into a small bile duct known as the cystic duct. The cystic duct connects to the common hepatic duct that carries bile from the liver. These ducts merge to form the common bile duct that extends to the wall of the duodenum.
The mucosa, which forms the innermost layer of the gallbladder, lines the gallbladder with simple columnar epithelial tissue. The columnar epithelial tissue contains microvilli on its surface, increasing the surface area and allowing the lining to absorb water and concentrate the dilute bile.
Beneath the columnar tissue is a thin lamina propria layer made of connective tissue and capillaries that support and anchor the epithelial layer.
Deep to the lamina propria is the muscularis layer that contains smooth muscle tissue. Contraction of the muscularis pushes bile out of the gallbladder and into the cystic duct.
Surrounding the muscularis is a thin layer of fibrous connective tissue that helps to reinforce and strengthen the wall of the gallbladder.
Finally, the serosa forms the outermost layer of the gallbladder. The serosa is an epithelial layer that forms part of the peritoneum, or lining of the abdominal cavity. The serosa gives the gallbladder a smooth, slick surface to prevent friction between moving organs.