Biology Support & Movement KMU 2024
PMDC Verified Question 16 of 75
What happens to calcium when skeletal muscles recover from contraction?
A
Released from the sarcoplasmic reticulum
B
Released from the myosin head
C
Pumped into the sarcoplasmic reticulum
D
Exchanged for sodium ions
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Pumped into the sarcoplasmic reticulum
Concept:

Termination of the excitation-contraction coupling.

Formula:

N/A (Conceptual)

Solution:

  • For a contracted muscle to safely relax and recover, the internal signal to contract (high cytosolic Calcium) must be rapidly removed.


  • To achieve this, high-affinity, ATP-driven Calcium pumps immediately engage, aggressively vacuuming the \(Ca^{2+}\) off the troponin molecules and actively pumping it back into the sarcoplasmic reticulum for safe storage until the next nerve impulse arrives.


Why other options are incorrect:

Releasing calcium from the SR causes contraction. Calcium never binds to the myosin head (it binds troponin). Exchanging it for sodium is part of cardiac regulation, not the primary skeletal muscle relaxation mechanism.

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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