Bile duct

Synonyms

Biliary tract

definition

The bile duct is part of a duct system between the liver, pancreas and intestines. In this the bile flows from the liver to the duodenum (Duodenum). In the broadest sense, the gallbladder can also be counted as part of the bile duct system.

anatomy

In the liver becomes bile educated. In addition to water, this bile contains bile salts and enzymes as well as metabolites from the liver. This bile ultimately has to go into the Intestines because it is here at the digestion contributes. The bile is especially necessary for the digestion and decomposition of fats. To get to their place of work, there is Bile duct or the bile ducts. These connect the liver with the Duodenum (Duodenum). The is located between the liver and the mouth of the duodenum, and thus also connected to the bile duct Gallbladder.

A distinction is made with the bile duct according to whether it is still in the liver runs (intrahepatic Bile ducts) or already outside the liver (extrahepatic Bile ducts).

A bile duct in the liver forms directly between the liver cells (hepatocytes) and runs through the corresponding liver lobule. This Bile duct basically does that Space between the opposing cells out. This bile duct or bile ducts are called Canaliculi biliferi. There are very many of these, as they run in a row between all liver cells. These canaliculi biliferi open into short switching or intermediate pieces (Hering - called canals). This bile duct is very small and has about one Diameter from 10-15 µm.

These herring canals then go into the so-called Periportal fields into another bile duct. These are then called the ductuli biliferi interlobulares, i.e. the Bile duct, the between the lobes runs. A periportal field is a characteristic structure of the liver. Several lobules of liver adjoin each other here. The so-called Glisson - triad. The Glisson triad include one artery, one vein and the Bile duct (Ductuli biliferi interlobulares).

Several of these Bile ducts (Ductuli biliferi interlobulares) then unite a little later to form another bile duct, the Ductus hepaticus dexter and sinister. These are two bile ducts that ultimately lead all of the bile formed in the liver out of the left (sinister) and right (dexter) lobes of the liver. Up to this point every bile duct is still in the liver (intrahepatic).

The Porta hepatica refers to the part of the liver where, among other things Blood vessels and Bile duct from the liver step out. Shortly before the porta hepatica, the two bile ducts of the left and right lobes unite to form a common bile duct. This is called Common hepatic duct.
From this bile duct, the following duct structures are included Biliary system outside the liver (extrahepatic).

The common bile duct (Common hepatic duct) is about 4 cm long. From this bile duct the bile flows into the Cystic duct. This bile duct leads to Gallbladder. Here can the produced Bile temporarily saved. At the junction of the hepatic duct and the cystic duct there is a final bile duct, the Common bile duct, ultimately until Duodenum. This last bile duct leads behind the Intestines to pancreas. Here it joins a duct that comes from the pancreas (Pancreatic duct) and flows together on the papilla duodeni major (Papilla Vateri) into the Duodenum (Duodenum).

histology

The first bile duct in the liver is formed only by the walls of the opposite liver cells. After these bile ducts open into the Hehring canals, the bile duct is lined with an epithelium. There are other cells here: Oval cells. The oval cells are Stem cells. This means that this results in damage to the liver tissue can form new cells.

What is special about the bile ducts, which follow the Hering canals, is that they are active here bicarbonate is secreted into the bile. That means that through the extra salt in the bile Passively water flows in. Thereby the volume of bile increases in this bile duct by 30%.

function

The bile duct serves that Drain the bile. This causes the bile to flow out of the liver first through the common hepatic duct (common duct from the liver) and the cystic duct into the Gallbladder.

The Gallbladder can be counted in the broadest sense of the bile duct system. The gallbladder is what is produced in the liver bile saved and thickened. Thickened means that water is withdrawn from the bile, making it thicker in consistency.

It comes to Ingestion and thus to one Digestive process, this solves the Release of bile out. This increases the secretion of bile in the liver and the muscle of the gallbladder wall contracts. Thus, the bile is released into the common bile duct and can move towards it pancreas and Duodenum flow away.

pathology

The bile duct can pathologically misplaced be. This case occurs either through a Gallstone one that lies in the bile duct, or through one tumorwhich can narrow the bile duct from the inside or outside. Gallstones, that are in the gallbladder are called Cholecystolithiasis designated.

Through the Relocation of the bile duct can it for Damming and backlogging of bile come (so-called Cholestasis). In doing so, the bile ducts within the liver can become pathological expand.

Especially with a very sudden obstruction of the bile duct by one Bile duct stone it can become strong and colicky Pain in the upper abdomen come. If, on the other hand, there is a slowly progressing relocation, as is the case with a growing one tumor is the case, pain is often absent.

At a Relocation of the bile duct is often one enlarged and elastic gall bladder externally palpable. The doctor can use the right costal arch the Edge of the liver and the one lying here Palpate the gallbladder.

A rare disease affecting the bile ducts in newborns is the Biliary atresia. The cause has not yet been clarified. With this disease, there is one Clasp (Atresia) of a bile duct and increasing number of inflammation of the bile ducts.

Biliary cysts are rare malformations of the bile duct. Here it comes to a Expansion of the bile ducts.