Fetal circulation Umbilical vein (oxygenated blood) parietalis Smooth Main stem villus Umbilical arteries (deoxygenated blood Amniochorionic membrane chorion .Sin,a 办 Decidua basalis Er 3. MATERNAL BLOOD PATHWAYS Placental septum 1. FETAL CIRCULATION IN 2. MATERNAL CIRCULATION THE VILLOUS TREE IN INTERVILLOUS SPACE Anchoringⅶilus xygenated blood B Deoxygenated blood