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STD 12 - 2. human reproduction — NEET STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceNEETSTD 12 - 2. human reproduction4 Marks
MCQ
Signals for parturition originate from
  • ✓
    both placenta as well as fully developed foetus
  • B
    oxytocin released from maternal pituitary
  • C
    placenta only
  • D
    fully developed foetus only.
✓

Answer

Correct option: A.
both placenta as well as fully developed foetus
a
(a) : 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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