2.4 The maternal blood and foetal blood are in close contact and never mix. What is the reason for this? How does substances move from mother to baby.

The reason maternal and fetal blood do not mix primarily lies in the structure of the placenta, which acts as a barrier. The maternal blood flows through intervillous spaces while the fetal blood circulates through chorionic villi, separated by a thin membrane. This design not only prevents mixing but also protects the fetus from potential pathogens and maternal blood factors. Substances move from mother to baby via diffusion, facilitated diffusion, and active transport through the placenta. Nutrients like glucose and oxygen pass through the placental membrane into the fetal circulation, while waste products from the fetus, such as carbon dioxide, move back to the mother for elimination. It's a beautiful, perfected exchange system that keeps the little one nourished while keeping them safe!