Biology Nervous Coordination NUMS 2024
PMDC Verified Question 18 of 86
Which option given below characterizes refractory period?
A
Change in the type of ions across the membrane
B
Membrane potential +50mV
C
Reversal of charges across neural (neuronal) membrane
D
Next impulse can be conducted
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Reversal of charges across neural (neuronal) membrane
Concept:

Neurons require a brief recovery window before they can fire again to ensure impulses travel in only one direction.

Solution:

  • The absolute refractory period occurs directly during the action potential, heavily characterized by the active reversal of charges (depolarization and immediate repolarization). Because the sodium channels are already open or inactivated during this massive charge reversal, it is impossible for the membrane to respond to a new stimulus until resting states are restored.


Why other options are incorrect:

  • Next impulse can be conducted: This is the exact opposite of what "refractory" means.


  • Membrane potential +50mV: This only describes the peak of the action potential, while the refractory period encompasses the falling phase as well.

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.

Previous Question All Nervous Coordination MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App