• Login/Register
  • Section: Health /Monday 13th October 2014

    Alphabetic Index : A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

    Search β):

    * Gallbladder *

    کیسه صفرا


    Iranian_Flag_Hand_Love_Heart.jpg
    (Wikipedia) - Gallbladder This is the latest accepted revision, accepted on 7 October 2014. For other uses, see Gallbladder (disambiguation). Gallbladder Latin Gray''s System Artery Vein Nerve Precursor MeSH Dorlands /Elsevier
    The gallbladder is located beneath the liver and drains bile into the duodenum via the biliary tree.
    The gallbladder connects to the liver via the cystic duct gross anatomy and local ducts connecting to the liver, pancreas and duodenum of the small intestine.
    Vesica biliaris, vesica fellea
    p.1197
    Digestive system
    Cystic artery
    Cystic vein
    Celiac ganglia, Vagus (CN X)
    Foregut
    Gallbladder
    12383343
    Anatomical terminology

    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. Humans can live without a gallbladder. The surgical removal of the gallbladder is called a cholecystectomy.

    Contents

    StructureParts of the gall bladder.

    The gallbladder is a hollow organ that sits just beneath the right lobe of 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. The gallbladder has a capacity of about 100 mL.:298

    The gallbladder is shaped like a tapered sac, with the open end opening into the biliary tree and the cystic duct. Anatomically, the gallbladder is divided into three sections: the fundus, body, and neck: The fundus is a rounded end that faces the front of the body. The body (Latin: corpus) is in contact with the liver, lying in depression at the bottom of the liver. The neck tapers and is continuous with the cystic duct, part of the biliary tree. The cystic duct unites with 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 fundus is at the same level as the transpyloric plane.

    HistologyMicrograph of a normal gallbladder wall. H&E stain.

    Under the microscope, the layers of the gallbladder wall can be seen. The gallbladder wall''s innermost surface is lined by a single layer of columnar cells with an apical brush border of microvilli, very similar to intestinal absorptive cells. Underneath the epithelia is an underlying lamina propria, muscularis, perimuscular layer and serosa. Unlike elsewhere in the intestinal tract, the gallbladder does not have a muscularis mucosae, and the muscular fibres are not arranged in distinct layers. In greater detail, the layers are:

    Development

    The gallbladder develops from an outpouching of the embryonic gut tube, an endodermal structure.

    Early in development, the human embryo has three layers and abuts an embryonic yolk sac. During the second week of embryological development, as the embryo grows, it begins to surround and envelop portions of this sac. The enveloped portions form the basis for the adult gastrointestinal tract. Sections of this gut begin to differentiate into the organs of the gastrointestinal tract, such as the oesophagus, stomach, and intestines.

    During the fourth week of embryological development, the stomach rotates. The stomach, originally lying in the midline of the embryo, rotates so that its body is on the left. This rotation also affects the part of the gastrointestinal tube immediately below the stomach, which will go on to become the duodenum. By the end of the fourth week, the developing duodenum begins to spout a small outpouching on its right side, which will go on to become the liver biliary tree. Just below this is a second outpouching, known as the cystic diverticulum, that will eventually develop into the gallbladder.

    Variation

    Anatomical variants of the gallbladder occur very rarely, although a range of abnormalities have been documented.

    The number and structure of the gallbladder may vary. Occasionally two or even three gallbladders may coexist, either as separate bladders draining into the cystic duct, or sharing a common branch that drains into the cystic duct. Additionally, the gallbladder may fail to form at all. Gallbladders with two lobes separated by a septum may also exist. These abnormalities are not likely to affect function and are generally asymptomatic.

    The location of the gallbladder with regard to the liver may also vary, with documented variants including gallbladders found within, above, on the left side of, behind, and detached from the liver. Such variants are very rare: from 1886 to 1998, only 110 cases of left-lying liver, or less than one per year, were reported in scientific literature.

    An anatomical variation is seen in the Phrygian cap, which is an innocuous fold in the fundus.

    Function1. Bile ducts: 2. Intrahepatic bile ducts, 3. Left and right hepatic ducts, 4. Common hepatic duct, 5. Cystic duct, 6. Common bile duct, 7. Ampulla of Vater, 8. Major duodenal papilla 9. Gallbladder, 10–11. Right and left lobes of liver. 12. Spleen. 13. Esophagus. 14. Stomach. Small intestine: 15. Duodenum, 16. Jejunum 17. Pancreas: 18: Accessory pancreatic duct, 19: Pancreatic duct. 20–21: Right and left kidneys (silhouette). The anterior border of the liver is lifted upwards (brown arrow). Gallbladder with Longitudinal section, pancreas and duodenum with frontal one. Intrahepatic ducts and stomach in transparency.

    The main purpose of the gallbladder is to store bile, also called gall. The gallbladder is part of the biliary system and serves as a reservoir for bile, which is produced by the liver. The liver produces the bile and then it flows through the hepatic ducts into the gallbladder. At any one time, 30-60 millilitres of bile is stored within the gallbladder.

    When food containing fat enters the digestive tract, it stimulates the secretion of cholecystokinin (CCK) from I cells of the duodenum and jejunum. In response to cholecystokinin, the gallbladder rhythmically contracts and releases its contents into the common bile duct, eventually draining into the duodenum. The bile, originally produced in the liver, emulsifies fats in partly digested food, thereby assisting their absorption. Bile consists primarily of water and bile salts, and also acts as a means of eliminating bilirubin, a product of hemoglobin metabolism, from the body.

    The bile that is secreted by the liver and stored in the gallbladder is not the same as the bile that is secreted by the gallbladder. During gallbladder storage of bile, it is concentrated by removal of some water and electrolytes. This is through the active transport of sodium ions across the epithelia of the gallbladder, which creates an osmotic pressure that also causes water and other electrolytes such as chlorine to be reabsorbed.

    Clinical significance Main article: Gallbladder disease Gallstone Main article: Gallstones

    Gallstones are the most common problem to affect the gallbladder. Gallstones generally form because the bile is saturated with either cholesterol or bilirubin. Only the minority of gallstones cause symptoms, and the majority of stones are passed along the biliary tree. When symptoms occur, a person may feel exquisite pain in the upper right part of their abdomen. If the stone blocks the gallbladder, cholecystitis may occur. If the stone lodges in the biliary tree, jaundice may occur; and if the stone blocks the pancreatic duct, then pancreatitis may occur. Gallstones are often managed by waiting for them to be naturally passed. In people with recurrent gallstones, surgery to remove the gallbladder may be considered. Some medication, such as UDCA, and ultrasound to break down the stones may also be used.

    Inflammation Main article: Cholecystitis

    Inflammation of the gallbladder is known as cholecystitis. Inflammation is most commonly because of obstruction of the duct with gallstones, known as cholelithiasis. Blocked bile accumulates, and pressure on the gallbladder wall may lead to the release of substances that cause inflammation, such as phospholipase. There is also the risk of bacterial infection. An inflamed gallbladder is likely to cause pain and fever, and tenderness in the upper, right corner of the abdomen, and may have a positive Murphy''s sign. Cholecystitis is often managed with rest and antibiotics, particularly cephalosporins and, in severe cases, metronidazole.

    Cholecystitis may also occur chronically, particularly when a person is prone to getting gallstones.

    Gallbladder removal Main article: Cholecystectomy

    A cholecystectomy is a procedure in which the gallbladder is removed. It may be removed because of recurrent gallstones, and is considered an elective procedure. A cholecystectomy may be an open procedure, or one conducted by laparoscopy. In the surgery, the gallbladder is removed from the neck to the fundus, and so bile will drain directly from the liver into the biliary tree. About 30% of patients may experience some degree of indigestion following the procedure, although severe complications are much rarer.

    Society and culture

    Numerous words in the English language relate to the gallbladder and the bile that it stores. To have ''gall'' is associated with bold behaviour, whereas to have ''bile'' is associated with bitterness.

    In the Chinese language, the gallbladder (Chinese: 胆) is associated with courage and a plethora of related idioms, including using terms such as "a body completely gall" (Chinese: 浑身是胆) to describe a brave person, and "single gallbladder hero" (Chinese: 孤胆英雄) to describe a lone hero.

    In the Zangfu theory of Chinese medicine, the gallbladder not only has a digestive role, but is seen as the seat of decision-making.

    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.

    Additional images

    Tags:Bile, Chinese, Gallbladder, Inflammation, Wikipedia


    See also items containing : Gallbladder

    Add definition or comments on Gallbladder

    Your Name / Alias:
    E-mail:
    Definition / Comments
    neutral points of view
    Source / SEO Backlink:
    Anti-Spam Check
    Enter text above
    Upon approval, your definition will be listed under: Gallbladder





    Happy Summer Sale

    Home About us / Contact    Products    Services    Iranian History Today    Top Iran Links    Iranian B2B Web Directory    Historical Glossary
    Copyright @ 2004-2016 fouman.com All Rights Iranian