Question

Write about the role of placenta in the development of embryo.

Answer 1

The placenta is a temporary organ formed during pregnancy. It connects the developing embryo or foetus to the mother through the umbilical cord. Maternal and foetal blood normally remain separate, but substances are exchanged across the placental barrier.

1. Nutrition: Glucose, amino acids, vitamins, minerals and other useful substances pass from the mother’s blood to the foetus.
2. Respiration: Oxygen passes from the mother’s blood to the foetal blood. Carbon dioxide moves in the opposite direction to be removed by the mother’s lungs.
3. Excretion: Waste products made by the foetus, including urea and carbon dioxide, pass into the mother’s blood for elimination.
4. Protection and transfer: The placenta acts as a selective barrier. Some maternal antibodies can cross it and provide the foetus with temporary protection, although not all harmful substances are blocked.
5. Hormone production: The placenta produces hormones, including human chorionic gonadotrophin (hCG), oestrogen and progesterone. Early in pregnancy, hCG helps maintain the corpus luteum; later, placental hormones help maintain the uterine lining and support pregnancy.

Thus, the placenta supports the growth of the embryo by enabling exchange between mother and foetus and by producing hormones needed to maintain pregnancy.