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Multiple Choice
The refractory period in which the muscle will NOT contract if stimulated occurs during __________ of the muscle cell.
A
polarization
B
hyperpolarization
C
repolarization
D
depolarization
Verified step by step guidance
1
Understand the concept of the refractory period: The refractory period is a phase during which a muscle cell is unable to respond to further stimulation. This is crucial for ensuring that muscle contractions are properly timed and coordinated.
Identify the phases of muscle cell action potential: Muscle cells undergo several phases during an action potential, including depolarization, repolarization, and hyperpolarization. Each phase has distinct characteristics and effects on the cell's ability to contract.
Depolarization phase: During depolarization, the muscle cell membrane potential becomes less negative, leading to the opening of voltage-gated sodium channels. This phase is typically associated with the initiation of muscle contraction.
Repolarization phase: In repolarization, the cell membrane potential returns to its resting state, primarily due to the efflux of potassium ions. This phase is crucial for resetting the cell's electrical state and is associated with the refractory period, where the muscle cell cannot contract.
Hyperpolarization phase: Hyperpolarization occurs when the membrane potential becomes more negative than the resting potential. This phase follows repolarization and further ensures that the muscle cell is temporarily unresponsive to stimulation.