||It has been suggested that Body of gallbladder be merged into this article. (Discuss) Proposed since July 2013.|
|Diagram of Stomach|
|Surface projections of the organs of the trunk, with gallbladder labeled at the transpyloric plane|
|Latin||Vesica biliaris, vesica fellea|
|Gray's||subject #250 1197|
|Nerve||Celiac ganglia, vagus|
In vertebrates the gallbladder (cholecyst, gall bladder or biliary vesicle) is a small organ where bile is stored, before it is released into the small intestine. In humans, the loss of the gallbladder, in most cases, is easily tolerated by the body. The surgical removal of the gallbladder is called a cholecystectomy.
The gallbladder is a hollow system that sits just beneath the liver. In adults, the gallbladder measures approximately 8 centimetres (3.1 in) in length and 4 centimetres (1.6 in) in diameter when fully distended. 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. At the neck of the gallbladder is a mucosal fold called Hartmann's pouch,where gallstones commonly get stuck. The angle of the gallbladder is located between the costal margin and the lateral margin of the rectus abdominis muscle.
The different layers of the gallbladder are as follows:
- The epithelium, a thin sheet of cells closest to the inside of the gallbladder
- The lamina propria, a thin layer of loose connective tissue (the epithelium plus the lamina propria form the mucosa)
- The muscularis, a layer of smooth muscular tissue that helps the gallbladder contract, squirting its bile into the bile duct
- The perimuscular ("around the muscle") fibrous tissue, another layer of connective tissue
- The serosa, the outer covering of the gallbladder that comes from the peritoneum, which is the lining of the abdominal cavity
Unlike elsewhere in the intestinal tract, the gallbladder does not have a muscularis mucosae.
When food containing fat (and amino acids) enters the digestive tract, it stimulates the secretion of cholecystokinin (CCK) from I cells of the duodenum and jejunum. In response to CCK, the adult human gallbladder, which stores about 50 millilitres (1.7 U.S. fl oz; 1.8 imp fl oz) of bile, contracts and releases its contents into the duodenum. The bile, originally produced in the liver, emulsifies fats in partly digested food.
During storage in the gallbladder, bile becomes more concentrated which increases its potency and intensifies its effect on fats.
In other animals
Most vertebrates have gallbladders, whereas invertebrates do not. However, its precise form and the arrangement of the bile ducts may vary considerably. In many species, for example, there are several separate ducts running to the intestine, rather than a single common bile duct, as in humans. Several species of mammals (including horses, deer, rats, and various laminis) and several species of birds lack a gallbladder altogether, as do lampreys.
- 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. Retrieved 2007-06-29.
- "Where is the Gallbladder Located in the Body". Buzzle.com. 2013-02-28. Retrieved 2013-08-18.
- Jon W. Meilstrup (1994). Imaging Atlas of the Normal Gallbladder and Its Variants. Boca Raton: CRC Press. p. 4. ISBN 0-8493-4788-2.
- "Staging of Gallbladder Cancer".
- Sahu S, Joglekar MV, Dumbre R, Phadnis SM, Tosh D, Hardikar AA. (2009) Islet-like cell clusters occur naturally in human gallbladder and are retained in diabetic conditions. J Cell Mol Med. 2009 May;13(5):999-1000
- C. Michael Hogan. 2008. Guanaco: Lama guanicoe, GlobalTwitcher.com, ed. N. Strömberg
- Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 355. ISBN 0-03-910284-X.
|Wikimedia Commons has media related to Gall bladder.|
- Diagram of Human Stomach and Gallbladder – Human Anatomy Online dd, MyHealthScore.com.
- www.newchronicles.webs.com/f/gastrointestinalphysiology – Gastrointestinal Physiology Review.