Gallbladder
The gallbladder (vesica fellea or biliaris, Latin vesica, bladder ' and Fellis or bilis, Galle ' ) is a hollow organ in vertebrates which serves the storage and thickening of the bile produced by the liver that is needed for the digestion of fats in the intestine. Erroneously, the gallbladder itself is often referred to as " bile ".
Occurrence
A gall bladder is formed in most vertebrates, the first time it occurs as a feature in the evolution of vertebrates. Within the classes of vertebrates, there are taxa that do not gall bladder is formed. They found, for example in lampreys only in young animals as adults it is reduced in the course of ontogenesis. In addition, a number of cartilaginous fish has no gall bladder. Of the mammals, sloths, giraffes, tapirs, horses, rats, and many deer have no gall bladder. Within the birds they lack in most pigeons birds and parrots as well as the Nandu and the African ostrich, guinea fowl, it is not always present.
Anatomical structure
Human gallbladder is normally 6 to 10 cm long and less than 4 cm. Their shape is often described as " pear-shaped ". The gallbladder is located in the gallbladder fossa ( fossa biliaris ) of the lower lobe of the liver between the quadratum (square flap ) and lobus dexter ( right lobe ), but can also be enclosed by the tissue of the liver. After the caudal organ is related to the flexure coli artery, the right-hand bend in the large intestine (colon ), which may lead to adhesions between the two institutions in inflammation, or even connections between the respective cavities ( biliodigestive fistula ). Dorsal ( back down) is the gall bladder medially close to the superior part of the duodenum (duodenum ). Wherein the snakes behind the gall bladder and the liver relatively far away from it.
The institution may in a fundus of bladder biliaris (gall bladder floor ), Corpus vesicae biliaris (gall bladder ) and the bladder cervix are classified biliaris (gall bladder neck). The neck of the gallbladder, where the organ in the cystic duct (gall bladder ) passes, has a spiral fold of mucous membrane ( plica spiralis, also Heister - flap ), a lock function, especially in increasing the intra-abdominal pressure (eg during defecation ) perceives. The cystic duct joins the common hepatic duct to the common bile duct, which runs in the hepatoduodenal ligament and empties into the duodenum.
The entire gallbladder is, with the exception of bodies that bear the liver, with abdominal membrane (peritoneum ) plated, which is sensitive innervated by the right phrenic nerve ( phrenic nerve ). The nerve fibers originate from the spinal cord segments C3 - C5. Of the segments C3 and C4 forth on this page, the fibers of the nervi supraclavicular innervating which parts of the right shoulder. If irritation of the peritoneum of the gall bladder by pathologic processes, such as inflammation, may occur in the shoulder due to this common origin to the phenomenon of " Transferred pain ". In addition, the gallbladder is vegetatively innervated by fibers of the celiac plexus.
The arteria cystica ( bladder artery), usually a vessel from the right branch of the hepatic artery ( hepatic artery ) supplies the gall bladder with blood. Laxative vessels are the veins cysticae that flow into the portal vein ( portal vein ).
With a variety that is called " Phrygian Cap ", is a ballooning of the institution, whose form of that cap may be similar.
For species without gallbladder of liver failure leadership transition opens directly into the duodenum.
The green color of the organ is due to the color of bile.
Feinbau
The approximately 0.4 cm thick wall of the hollow organ is divided histologically in three layers. From the inside (lumen) to the outside, a distinction is a tunica mucosa consisting of epithelium and a lamina propria, a muscularis and serosa.
The tunica mucosa ( mucous membranes ) is composed of a lumen located forward surface epithelium layer and an underlying layer of connective tissue with blood vessels of the lamina propria. The mucous membrane is raised to wrinkles that are smoothed with increasing filling. The juxtaposition of wrinkles leading to so-called " mucosal bridges", which are characteristic of the histological preparation of a gall bladder. See occasional crypts are called Rokitansky - Aschoff crypts. The surface epithelium consists of so-called principal cells, is single-layered and is characterized by a large number of microvilli. The cells are connected by Nexus, desmosomes and final bars. Function of the main cells is the removal of water to the concentration of the bile and the production of slime to protect the organ from bile constituents. In some mammals ( carnivores, artiodactyls ) has the mucosa in the area of the gallbladder neck mucous glands that synthesize mucins. In chronic inflammation, the number of these glands can be increased.
The middle of the three layers, the thin tunica muscularis consists of smooth muscle in three-dimensional orientation and occasional connective tissue components. The layer is necessary for the support of the emptying of the organ.
The exterior serosa is, except at the location adjacent the liver where a tunica adventitia is formed from the epithelium of the peritoneum and underlying connective tissue. This layer performs next to nerve fibers and blood vessels.
Ontogenetic development
The gallbladder is in ontogenesis, the development of the individual organism, from a primitive gut tube out that in the fourth week of development from the endoderm, the inner germ layer of the embryo blasts forms. The cranial ( against the skull ), this portion of this pipe is called the foregut and is among other things, the starting point for the development of liver and gallbladder. The latter is evident from the Cystic diverticulum, an outpouching of the foregut, which lies cranial to the system of the pancreas and caudal ( tail down) to the liver primordium ( hepatic diverticulum ). From the diverticulum cystic both the gallbladder and the cystic duct ( bile duct) develops.
Both the lack and the dual system of the organ belong to a variety of rare malformations that are possible in humans. Also, the formation of direct transitions from the liver to the gallbladder is possible.
Physiology
Bile produced by the liver is the digestion of fats in the intestine. About the common bile duct, the bile is delivered via the major duodenal papilla in the duodenum. The sphincter ( sphincter ampullae and sphincter ductus choledochi ) in the area of the mouth can prevent the outflow of bile, so this is backed up in the cystic duct through the intermediary gallbladder through their contraction. This storage is mainly between meals ( interdigestiv ) and affects about half of the secreted by the liver bile. The institution holds about 50 ml of bile, the concentration of which can be but greatly increased by the active removal of water. Bile can be as up to ten percent of the original volume of enriched ( " thickened " ) are. Some of the original " liver bile " of the modified " gallbladder bile ", a distinction in this context. The latter is characterized primarily by an increased concentration of bile acids, lecithin, bile pigments and cholesterol. The thickening is carried out by the displacement of the sodium and chloride ions by use of a Na / H - and of a Cl-/HCO3--Antiport-Transportsystems in the apical ( luminal ) membrane of the main cell. This shift is electrically neutral, that is, no charges will be doing net moved. The water contained in the bile follows this absorbed ions due to their osmotic effect. In the basolateral membrane of the cell is a Na / K -ATPase, which keeps the intracellular sodium concentration constant. Absorbed water is transported in the blood vessels of the lamina propria.
For relaxation (relaxation) of the sphincter it comes to discharging the contents of the gall bladder; supports this drain is determined by the contraction of the smooth muscle of the gall bladder wall. The contraction takes place under the influence of cholecystokinin ( CCK), whose formation in the duodenum and upper jejunum ( jejunum ) is stimulated by, among other fat in the chyme, and the parasympathetic activity of the vagus nerve via the neurotransmitter acetylcholine.
Investigation procedure
To evaluate the gall bladder and bile ducts as well as any morbid phenomena, a variety of study options available, of which the ultrasound is the most common.
A healthy gall bladder is not palpable, in the context of inflammation, it may be delineated at any concomitant enlargement of the ventral border of the liver. Even when enlarged as part of drainage disorders in combination with jaundice the organ is palpable gallbladder (Courvoisier's sign). In the area of the ribs is usually also a sensitivity to pressure during inhalation before ( Murphy's sign ).
Another imaging method for assessing the gallbladder is the X-ray imaging after the administration of a contrast agent, a technique which is referred to collectively as a cholangiography at the gallbladder. The contrast agent, which makes the body represented, can be given orally or intravenously, but also in the context of endoscopic retrograde cholangiopancreatography ( ERCP) are using an endoscope, injected directly into the major duodenal papilla, the mouth of the biliary system into the duodenum. A further possibility is the percutaneous transhepatic cholangiography (PTC ) that during percutaneous the contrast agent, that is through the skin, is introduced by means of a puncture in the liver.
Diseases
Gallstones are loss products from the bile. In about 12 % of the German population, these concretions occur, but are symptomatic only in about half of those affected. The causes may be, for example an imbalance in the bile components bile acid and cholesterol. If bile acid enterohepatic circulation reinforced lost, such as in Crohn's disease due to inadequate absorption, or is deemed inadequate formed so takes the cholesterol proportion to relative. This also applies to an elevated cholesterol level ( hypercholesterolemia ). Other substances be stored on the nucleation of the following, which may lead to cholelithiasis ( gallstones ). Especially when very young people are severely affected, the cause may be in a structure disorder of the red blood pigment (porphyria), its precursor products damage the bile duct cells.
This condition may be due to irritation of the organ wall lead to cholecystitis, an acute or chronic inflammation of the gallbladder, which may result in an accumulation of pus in the hollow organ ( gall bladder ). Stone disease often go hand in hand with abdominal pain, colic and jaundice. Treatment options include the removal of the gallbladder ( cholecystectomy) or the removal with or without destruction of the stones as part of a Endoscopic retrograde cholangiopancreatography.
A Stauungsgallenblase ( gallbladder ) is caused by the relocation of the efferent bile ducts by gallstones, strictures or tumors accompanied by continued production of mucins. In the context of such Stauungsgallenblase or chronic cholecystitis, it may be a so-called " porcelain gallbladder " whose calcified wall by intercalation of calcium and so hardened.
As Gallenblasenperforation or Gallenblasenruptur the breakthrough of the gallbladder wall is called. This can be either the result of cholecystitis and a mechanical load.
Various known as liver fluke flukes infest the biliary tree and the gallbladder.
By chronic inflammation of the gallbladder, it can also lead to a scarred shrink gallbladder.
The gallbladder carcinoma is a malignant tumor that can affect not only the gallbladder and the efferent bile ducts. It is favored by gallstones and is due to the laid biliary tract usually accompanied by jaundice (icterus). The gallbladder can be enlarged.
The removal of the gall bladder as a result of a stone or cancerous condition is called a cholecystectomy and can conventionally (opening of the abdomen) or, more common today, are minimally invasive, performed under laparoscopy. For this procedure the patient adult usually only have problems if the diet is characterized by excessive fatty foods.
By means of an anastomosis can also biliodigestive an artificial link between the gallbladder or the bile duct system and parts of the intestinal tract are produced.