What is a biliary tract?

Answer 1

The biliary tract consists of the liver, gallbladder, and bile ducts.A hepatocyte is a cell of the main parenchymal tissue of the liver. Hepatocytes make up 80% of the liver's mass. These cells are involved in:

*Protein synthesis

*Protein storage

*Transformation of carbohydrates

*Synthesis of cholesterol, bile salts and phospholipids

*Detoxification, modification, and excretion of exogenous and endogenous substances

*Initiation of formation and secretion

Bile canaliculus (plural:bile canaliculi; also called bile capillaries) is a thin tube that collects bile secreted by hepatocytes. The bile canaliculi empty into a series of progressively larger bile ductules and ducts, which eventually become common hepatic duct. The bile canaliculi empty directly into the Canals of Hering.

Hepatocytes are polyhedral in shape, therefore having no set shape or design, although they are made of cuboidal epithelial cells. They have surfaces facing the sinusoids, (called sinusoidal faces) and surfaces which contact other hepatocytes. The interlobular bile ducts (or interlobular ductules) carry bile in the liver between the Canals of Hering and the interlobar bile ducts. They are part of the interlobular portal triad and can be easily localized by looking for the much larger portal vein. The cells of the ducts are described as cuboidal epithelium with increasing amounts of connective tissue around it., (called lateral faces). Bile canaliculi are formed by grooves on some of the lateral faces of these hepatocytes.

Microvilli are present in the canaliculi.

The canals of Hering, or intrahepatic bile ductules, are part of the outflow system of exocrine bile product from the liver. Liver stem cells are located in the canals of Hering.

The interlobular bile ducts (or interlobular ductules) carry bile in the liver between the Canals of Hering and the interlobar bile ducts. They are part of the interlobular portal triad and can be easily localized by looking for the much larger portal vein. The cells of the ducts are described as cuboidal epithelium with increasing amounts of the connective tissue around The interlobular bile ducts (or interlobular ductules) carry bile in the liver between the Canals of Hering and the interlobar bile ducts. They are part of the interlobular portal triad and can be easily localized by looking for the much larger portal vein. The cells of the ducts are described as cuboidal epithelium with increasing amounts of connective tissue around Intrahepatic bile ducts compose the outflow system of exocrine bile product from the liver.

They can be divided into:

Lobar ducts (right and left hepatic ducts) - stratified columnar epithelium.

Interlobar ducts (between the main hepatic ducts and the interlobular ducts) - pseudostratified columnar epithelium. Interlobular bile ducts (between the interlobar ducts and the lobules) - simple columnar epithelium.

Intralobular bile ducts (cholangioles or Canals of Hering) - simple cuboidal epithelium, then by hepatocytes

Bile canaliculi - two half-canaliculi formed by the hepatocytes facing the perisinusoidal space.

The common hepatic duct is the first part of the biliary tract. It joins the cystic duct coming from the gallbladder to form the common bile duct. The cystic duct is the short duct that joins the gallbladder to the common hepatic duct. It usually lies next to the cystic artery. It is of variable length. It contains 'spiral valves of Heister', which do not provide much resistance to the flow of bile. In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although the structure and position of the gallbladder can vary significantly among animal species. It receives and stores bile, produced by the liver, via the common hepatic duct, and releases it via the common bile duct into the duodenum, where the bile helps in the digestion of fats. The common bile duct, sometimes abbreviated as CBD, is a duct in the gastrointestinal tract of organisms that have a gallbladder. It is formed by the confluence of the common hepatic duct and cystic duct and terminates by uniting with pancreatic duct, forming the ampulla of Vater. The flow of bile from the ampulla of Vater into the duodenum is under the control of the sphincter of Oddi.

When the sphincter of Oddi is closed, newly synthesized bile from the liver is forced into storage in the gallbladder. When open, the stored and concentrated bile (now mixed with pancreatic secretions) exits into the duodenum and takes part in digestion. This conduction of bile is the main function of the common bile duct. The hormone cholecystokinin, when stimulated by a fatty meal, promotes bile secretion by increased production of hepatic bile, contraction of the gallbladder, and relaxation of the sphincter of Oddi.

Answer 2

A biliary tract is the path by which bile is secreted and delivered to the duodenum.