Question

Student to attempt either option (A) or (B):
(A) “A fully developed foetus initiates its delivery from the mother’s womb.” Explain.
OR
(B) Give reasons for the following:

• Why can a woman generally not conceive a child after 50 years of age?
• Polar bodies are formed during oogenesis and not during spermatogenesis.

Hint:

Delivery is triggered by oxytocin via foetal signals. Polar bodies form in oogenesis due to unequal divisions, unlike spermatogenesis.

Answer 1

(A) Stage 1: Hormonal signals are transmitted from a mature fetus to the mother's body.
Stage 2: Mild uterine contractions initiate the fetal ejection reflex.
Stage 3: This leads to the maternal pituitary releasing oxytocin.
Stage 4: Oxytocin intensifies uterine contractions in a positive feedback cycle until birth.
OR
(B) (i) Typically after 50 years of age, women experience menopause, characterized by the cessation of egg release from the ovaries and hormonal support for conception. (ii) In oogenesis, unequal cytoplasmic division ensures the ovum retains ample cytoplasm, with small, non-functional cells called polar bodies produced concurrently. Conversely, spermatogenesis involves equal division, resulting in four viable sperm and the absence of polar bodies.