Abstract
This chapter focuses on knowledge of the newly discovered network of multiple stem/progenitor cell populations present primarily in the biliary tree and giving rise to maturational lineages of cells forming liver and pancreas throughout life. It summarizes information regarding key paracrine signals from lineage‐dependent epithelial–mesenchymal cell interactions in the maturational processes and found useful for ex vivo maintenance and differentiation of hepato/biliary and pancreatic cells at particular lineage stages. The phenomena associated with stem/progenitor cell maturational lineages in hepatic and pancreatic organogenesis are evident in all mammals studied but with a few distinctive variations in some species. The liver, biliary tree, and pancreas derive from midgut endoderm established at the gastrulation stage of early embryonic development. The peribiliary glands occur throughout the biliary tree as intramural glands, found within the bile duct walls, and as extramural glands that are tethered by extensions to the large bile ducts.