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STD 12 - 2. human reproduction — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYSTD 12 - 2. human reproduction1 Mark
MCQ
The foetal ejection reflex in humans triggers the release of
  • A
    oxytocin from foetal pituitary
  • B
    human chorionic gonadotropin $(hCG)$ from placenta
  • C
    human placental lactogen $(hPL)$ from placenta
  • ✓
    oxytocin from maternal pituitary.
✓

Answer

Correct option: D.
oxytocin from maternal pituitary.
d
(d) : 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. The stimulatory reflex between the uterine contraction and oxytocin secretion continues resulting in stronger and stronger contractions. This lead to expulsion of the baby out of the uterus through the birth canal.

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