Question

multiple choice question
when a nerve stimulates a skeletal muscle fiber, the response of the sarcolemma is to increase its permeability to

o acetylcholine
o calcium
o sodium

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Explanation:

When a nerve stimulates a skeletal - muscle fiber, an action potential is generated. The first step in this process is the opening of sodium channels in the sarcolemma, which increases its permeability to sodium ions. Sodium ions then rush into the muscle fiber, depolarizing the membrane. Acetylcholine is a neurotransmitter that binds to receptors on the sarcolemma to initiate the process, not a ion whose permeability is directly increased first. Calcium ions are involved later in the contraction process, after the initial depolarization.

Answer:

sodium