Gallbladder
From Wikipedia, the free encyclopedia
| Gall Bladder | |
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| Gall bladder is #5 | |
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| Diagram of Stomach | |
| Latin | vesica fellea |
| Gray's | subject #250 1197 |
| System | Digestive system (GI Tract) |
| Artery | Cystic artery |
| Vein | Cystic vein |
| Nerve | Celiac ganglia, vagus[1] |
| Precursor | Foregut |
The gallbladder (or cholecyst, sometimes gall bladder) is a small non-vital organ which aids in the digestive process and concentrates bile produced in the liver.
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[edit] Human anatomy
The gallbladder is a hollow organ that sits in a concavity of the liver known as the gallbladder fossa. In adults, the gallbladder measures approximately 10 cm in length and 4 cm in diameter when fully distended.[2] It is divided into three sections: fundus, body, and neck. The neck tapers and connects to the biliary tree via the cystic duct, which then joins the common hepatic duct to become the common bile duct.
[edit] Microscopic anatomy
The different layers of the galbladder are as follows:[3]
- The gallbladder has a simple columnar epithelial lining characterized by recesses called Aschoff's recesses, which are pouches inside the lining.
- Under the epithelium there is a layer of connective tissue (lamina propria).
- Beneath the connective tissue is a wall of smooth muscle (muscularis externa) that contracts in response to cholecystokinin, a peptide hormone secreted by the duodenum.
- There is essentially no submucosa separating the connective tissue from serosa and adventitia, but there is a thin lining of muscular tissue to prevent infection.
[edit] Function
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This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2008) |
The gallbladder stores about 50 mL (1.7 US fluid ounces / 1.8 Imperial fluid ounces) of bile, which is released when food containing fat enters the digestive tract, stimulating the secretion of cholecystokinin (CCK). The bile, produced in the liver, emulsifies fats 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. Most digestion occurs in the heat.
Most vertebrates have gallbladders (exceptions include the horse, cervids, and the rat), while invertebrates do not.
The human gallbladder is shaped like a pear, although the organ's shape and function vary considerably among other mammalian species; in fact, in some species, such as the lamoids, the gallbladder is absent.[4]
[edit] Abnormal conditions
Gallstones may develop in the gallbladder as well as elsewhere in the biliary tract. If gallstones in the gallbladder are symptomatic and cannot be dissolved by medication or broken into small pieces by ultrasonic waves, surgical removal of the gallbladder, known as cholecystectomy, may be indicated.
Other indications for this procedure include porcelain gallbladder and gallbladder cancer.
[edit] References
- ^ Ginsburg, Ph.D., J.N. (2005-08-22). "Control of Gastrointestinal Function". in Thomas M. Nosek, Ph.D.. Gastrointestinal Physiology. Essentials of Human Physiology. Augusta, Georgia, United State: Medical College of Georgia. pp. p. 30. http://www.lib.mcg.edu/edu/eshuphysio/program/section6/6ch2/6ch2line.htm. Retrieved on 2007-06-29.
- ^ Jon W. Meilstrup (1994). Imaging Atlas of the Normal Gallbladder and Its Variants. Boca Raton: CRC Press. pp. 4. ISBN 0-8493-4788-2.
- ^ "Slide 5: Gall Bladder". JayDoc HistoWeb. University of Kansas. http://www.kumc.edu/instruction/medicine/anatomy/histoweb/epithel/epith05.htm. Retrieved on 2007-06-29.
- ^ C. Michael Hogan. 2008. Guanaco: Lama guanicoe, GlobalTwitcher.com, ed. N. Strömberg
[edit] External links
- Diagram of Human Stomach and Gallbladder – Human Anatomy Online, MyHealthScore.com.
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