TY - CHAP M1 - Book, Section TI - Chapter 427. The Biliary Tract A1 - Rudolph, Colin D. A1 - Rudolph, Abraham M. A1 - Lister, George E. A1 - First, Lewis R. A1 - Gershon, Anne A. PY - 2011 T2 - Rudolph's Pediatrics, 22e AB - In the human embryo the first anlage of the bile ducts and liver is the hepatic diverticulum from the proximal gastrointestinal tract, as described in Chapter 418. The caudal part of this bud, known as the pars cystica, grows in length and forms the gallbladder, cystic duct and common bile duct. At about the eighth week of gestation, the hepatic precursor cells that lie adjacent to the hilar portal vein vessels form a sleeve-like double layer of cells that extends toward the periphery along the smaller intrahepatic portal vein branches. These hepatoblasts strongly expresses biliary specific cytokeratins and can be considered biliary precursor cells, that then form a continuous single-layered ring around the portal mesenchyme, known as the ductal plate.1 Beginning at 12 weeks of gestation and extending into the postnatal period, the ductal plate undergoes progressive remodeling. As new ductules form they are incorporated into the periportal mesenchyme that surrounds the portal vein branches. Thus, during successive periods of fetal life, ductal plate remodeling leads to the formation of the intrahepatic biliary tree. The largest ducts are formed first, followed by segmental, interlobular, and, finally, the smallest bile ductules. Arrest or derangement in remodeling leads to the persistence of primitive bile duct configurations termed ductal plate malformations. The occurrence of ductal plate malformations at different generations of the developing biliary tree gives rise to different clinicopathologic entities, such as congenital hepatic fibrosis and Caroli syndrome. SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accesspediatrics.mhmedical.com/content.aspx?aid=7039151 ER -