Biology Chemical Coordination PMC 2020
PMDC Verified Question 40 of 50
Which body function is controlled through positive feedback mechanism?
A
Labour contractions
B
Insulin production
C
Body temperature
D
Thyroxin release
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Labour contractions
Concept:

A positive feedback loop amplifies the initial stimulus, pushing the physiological process further away from its starting state to achieve a definitive endpoint.

Solution:

  • During childbirth, the baby's head pushes against the cervix. Stretch receptors signal the hypothalamus to release oxytocin.


  • Oxytocin causes the uterus to contract violently, which pushes the baby harder against the cervix, triggering the release of even more oxytocin. This explosive cascade of labor contractions continues until the baby is delivered.


Why other options are incorrect:

Insulin, body temperature, and thyroxin release are all strictly regulated by negative feedback loops to maintain a steady baseline.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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