Question

Explain the events that take place once a sperm reaches the oviduct till it becomes a foetus. Write the role of placenta in pregnancy.

Answer 1

• Fertilization: When a sperm reaches the oviduct, it fuses with an ovum to form a zygote.
• Zygote Development: The zygote undergoes mitotic divisions (cleavage) to form a multicellular embryo.
• Implantation: The embryo moves to the uterus and implants in the uterine wall, beginning the formation of a fetus.
• Fetus Development: The embryo differentiates into specialized tissues and organs, eventually becoming a fetus.
• Role of Placenta:
– Facilitates the exchange of nutrients, oxygen, and waste between the mother and fetus.
– Produces hormones like progesterone and estrogen to support pregnancy.