Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?
A) Sodium ions rush into the cell.
B) Acetylcholine (ACh) binds to receptors on the sarcolemma and allows passage of sodium ions into the cell.
C) Potassium ions diffuse out of the muscle cell.
D) The sodium-potassium pump restores sodium and potassium back to their initial positions.
E) Acetylcholinesterase (AchE) breaks down acetylcholine (ACh).

Question

Quizplus · Accepted Answer

Acetylcholine (ACh) needs to bind to receptors on the sarcolemma and allow passage of sodium ions into the cell through ligand-gated channels. This triggers depolarization of the cell and generates an action potential, which leads to muscle contraction. The other options describe events that occur during or after muscle contraction.

Which of These Events Must Occur First to Trigger the Skeletal