The parturition is induced by a complex neuroendocrine mechanism. Which of the following hormone is not involved in this process?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Melanin
Option (1) Estrogen — Involved. Signals from the foetus and placenta involve estrogen.
Option (2) Cortisol — Involved. Cortisol is one of the signals.
Option (3) Oxytocin — Involved. Oxytocin causes strong uterine contractions.
Option (4) Melanin — Not involved. NCERT says parturition is set off by signals from the foetus and placenta and by oxytocin from the maternal pituitary. Melanin is a skin pigment, not a hormone.
NCERT Extract:
Parturition and Lactation – “… Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscle and causes stronger uterine contractions, which in turn stimulates further secretion of oxytocin.”