Review: Epithelial aspects of human placental trophoblast.

The placenta must act as a surrogate lung, gastrointestinal tract and kidney for the fetus as well as acting as an endocrine gland necessary for the maintenance of a successful pregnancy: to achieve this, to what extent does the trophoblast necessarily share a similar epithelial phenotype? Here I review from a historical and a contemporary perspective some relevant studies with an emphasis on the similarities and differences between small intestinal and trophoblast biology. Certain physiological, structural and cell biological similarities are striking.