AIIMS 2019 Zoology Parturition MCQ Question
The process of delivery of foetus (childbirth) is called parturition. Parturition is induced by a complex neuroendocrine mechanism. The signals for parturition originate from the fully developed foetus and the placenta which induces mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscles and causes stronger uterine contractions which in turn stimulate further secretion of oxytocin.
Relaxin
Oxytocin
Prolactin
Estrogen
Correct Answer
Detailed Explanation
Parturition is primarily regulated by the hormone estrogen, which plays a crucial role in preparing the uterus for labor by increasing the sensitivity of uterine muscles to oxytocin and promoting the expression of oxytocin receptors. While oxytocin (option B) is essential for stimulating uterine contractions during labor, it is the rise in estrogen levels that initiates the parturition process. Relaxin (option A) is involved in softening the cervix and pelvic ligaments, but it does not directly induce labor. Prolactin (option C) primarily regulates lactation and does not play a significant role in the childbirth process.
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