Final answer:
The placenta is not impenetrable and does allow for the transfer of certain substances between the mother and the fetus, while also providing passive immunity through the transfer of antibodies.
Step-by-step explanation:
The placenta is not impenetrable and does allow for the transfer of certain substances between the mother and the fetus. While it serves as a barrier to prevent direct mixing of maternal and fetal blood, it does allow for the transfer of nutrients, oxygen, and waste products. Additionally, some pathogens are capable of crossing the placental barrier, which can pose a risk to the fetus. However, the placenta does provide passive immunity to the fetus by allowing the transfer of antibodies from the mother's body to protect against certain infections.
The statement is false; the placenta is not completely impenetrable. It allows antibodies and some pathogens to cross from the mother to the fetus, and also permits the exchange of various substances, including nutrients and waste products, while preventing the mixing of maternal and fetal blood cells.
The statement that the placenta is impenetrable and ensures no antibodies or viruses can cross the placental barrier is false. While the placenta does act as a barrier between the mother and fetus, it is not completely impermeable. Antibodies produced in the mother's body are often passed to the infant, providing passive immunity. The placenta is also permeable to certain pathogens known by the acronym TORCH, and to lipid-soluble substances, including some potentially harmful substances like alcohol, nicotine, and certain medications.
The placental barrier operates through structures called chorionic villi, which provide a large surface area for the exchange of substances between maternal and fetal blood. The placenta allows for the transfer of nutrients, oxygen, and waste products, but prevents blood cells from commingling, protecting the fetus from the mother's immune system and vice versa.