Tags: Anatomical Structure, Embryology.
Chorionic villi are villi that sprout from the chorion in order to give a maximum area of contact with the maternal blood.They are the sine qua non of pregnancy from a histomorphologic perspective and are by definition products of conception.Embryonic blood is carried to the villi by the branches of the umbilical arteries and after circulating through the capillaries of the villi is returned to the embryo by the umbilical veins.Thus the villi are part of the border between maternal and fetal blood during pregnancy.
