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Parturition

Hardbiology

Which factor significantly increases uterine contractions near term?

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About This Question

Subject
biology
Chapter
reproduction
Topic
parturition
Difficulty
Hard
Year
2025
Tags
ParturitionHormones

Solution

Correct Answer:

High oxytocin receptors sensitivity

  1. Parturition Mechanism: The process of childbirth is induced by a complex neuroendocrine mechanism.
  2. Hormonal Shift: Toward the end of pregnancy, the ratio of estrogen to progesterone rises.
  3. Receptor Regulation: High estrogen levels cause the uterine muscle (myometrium) to increase its sensitivity to oxytocin by synthesizing more oxytocin receptors.
  4. Positive Feedback: Uterine contractions stimulate the fetal ejection reflex, leading to more oxytocin release from the maternal posterior pituitary, which in turn causes stronger contractions.
  5. Prostaglandins: These also increase (not decline) to soften the cervix and enhance contractions.

This hard difficulty biology question is from the chapter reproduction, covering the topic of parturition. It appeared in the 2025 exam.

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