What structure allows for the transfer of oxygen and nutrients from the maternal circulation into fetal circulation?

• A. Placenta
• B. Umbilical cord
• C. Amniotic sac
• D. Chorion

Answer: (B)

The correct structure that facilitates the transfer of oxygen and nutrients from maternal circulation to fetal circulation is the placenta. The placenta is a unique organ that forms during pregnancy, providing a critical interface between maternal and fetal blood supplies. It allows for the exchange of gases (like oxygen and carbon dioxide), nutrients, and waste products without the two blood supplies mixing directly.

The umbilical cord serves as the conduit that transports blood between the placenta and the fetus, but it does not directly carry out the exchange functions; that is the role of the placenta. Meanwhile, the amniotic sac serves to protect and cushion the fetus, and the chorion is one of the membranes that contribute to the formation of the placenta but does not itself facilitate the direct exchange of substances. The placenta is, therefore, the primary structure responsible for the vital transfer processes that ensure the developing fetus receives the necessary nutrients and oxygen for growth and development.