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Organogenesis
The anlage of the biliary ducts and liver consists of a diverticulum that appears on the ventral aspect of the foregut in 3 mm embryos. The cranial portion becomes the liver; a caudal bud forms the ventral pancreas; and an intermediate bud develops into the gallbladder.
Originally hollow, the hepatic diverticulum becomes a solid mass of celLiverls that later recanalizes to form the ducts. The smallest ducts—the bile canaliculi—first appear as a basal network between the primitive hepatocytes that eventually expands throughout the liver.