The epithelial lining of the biliary tree is derived from which germ layer?

The epithelial lining of the biliary tree is derived from which germ layer?

• A. Mesoderm
• B. Ectoderm
• C. Endoderm
• D. Neural crest

Answer: (C)

The lining of the biliary tree comes from endoderm because, in early development, the foregut endoderm forms the liver and biliary ducts. The hepatic diverticulum—the liver bud—arises from this endoderm and differentiates into hepatocytes as well as the cholangiocytes that line the bile ducts. Surrounding tissues such as connective tissues and blood vessels come from the mesoderm, while ectoderm gives rise to skin and nervous system components, with neural crest cells arising from ectoderm as well. So the biliary epithelium is endodermal in origin.

The lining of the biliary tree comes from endoderm because, in early development, the foregut endoderm forms the liver and biliary ducts. The hepatic diverticulum—the liver bud—arises from this endoderm and differentiates into hepatocytes as well as the cholangiocytes that line the bile ducts. Surrounding tissues such as connective tissues and blood vessels come from the mesoderm, while ectoderm gives rise to skin and nervous system components, with neural crest cells arising from ectoderm as well. So the biliary epithelium is endodermal in origin.