The gall bladder is a sac-like reservoir for the bile secreted by the liver, below which it is located. It is an elongated organ, with a wide bottom that tapers towards the other end (neck) where the exit opening is situated. Thus, the gall bladder consists of a fundus (the widest part), a body (the middle portion), and a neck (the narrowest part). The length of this organ varies from 9 to 14 cm, while its width measures between 3 and 5 cm, giving it an average capacity of 60 cm3 (cubic centimeter). It is dark green in color and its wall is relatively thin. A cystic duct connects it to the common hepatic duct, which discharges bile into the duodenum through the common bile duct; all three conduits are collectively known as the biliary ducts. Function: it works as a reservoir for the bile produced by the liver.
This bile-containing sac lies on the lower surface of the liver, in the fossa for the gall bladder. Therefore, it is mesoperitoneal. Its superior surface is attached to the fibrous coat of the liver by areolar tissue. It free surface facing downwards into the abdominal cavity is covered by the visceral peritoneum, which passes onto it from the adjacent areas of the liver. In some cases, the gall bladder may be intraperitoneal and may even have a mesentery (a fold of the peritoneum which connects a visceral organ to the dorsal abdominal wall). Meanwhile, its fundus (bottom widest portion) projects downwards onto the anterior abdominal wall from under the notch of the liver and it is usually completely covered by the peritoneum.
Structure
The gall bladder composed of three layers: 1) a serous coat, which consists of mesothelium; 2) a muscular coat, which is formed by a single circular layer of smooth muscle, with bundles of longitudinal and oblique fibers; 3) a mucous coat, which is thin, forming numerous small folds. In the region of the neck, this mucous coat has a few spirally-arranged folds passing next to one another; these are called the spiral valves, which are also present in the cystic duct. The mucous coat of the gall bladder is lined with single layer of columnar epithelium. Glands are embedded in this layer.
Medical condition
Gallstones sometimes form inside of the gallbladder when it does not empty for a long time, and the bile is saturated with bilirubin. This causes inflammation and is painful. This organ does not empty its full content of bile into the duodenum when the diet is poor in fat, but rich in carbohydrates. This proves that it is more natural to consume saturated fat-rich nutrients than sugars and starch.
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| Schematic picture of gall bladder and the biliary ducts. |
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