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Question #45384
The Question
A pregnant female at full term is administered exogenous progesterone to artificially delay parturition. Despite normal fetal cortisol secretion initiating the fetal ejection reflex, sustained rhythmic uterine contractions fail to occur. Which of the following best explains the primary physiological reason for this failure?
Options
- A.
Exogenous progesterone directly inhibits the synthesis of oxytocin in the maternal posterior pituitary.
- B.
The sustained high progesterone levels prevent the estrogen-mediated upregulation of oxytocin receptors in the myometrium.
- C.
Progesterone competitively antagonizes oxytocin at the myometrial receptor sites, blocking the positive feedback loop.
- D.
The fetal ejection reflex is blocked because progesterone prevents the release of relaxin from the placenta.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Oxytocin|Progesterone|Positive_Feedback_Loop
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'progesterone maintains pregnancy' but fail to connect its withdrawal to the molecular sensitization of the myometrium (oxytocin receptor upregulation).
Additionally, Option A employs a classic NEET location trap by stating oxytocin is 'synthesized' in the posterior pituitary, testing the student's foundational endocrine knowledge.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Reproduction - Class 12 |
| Concept | Parturition Neuroendocrine Reflex |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |