Scelta multipla
Triggering of the muscle action potential occurs after which of the following events?
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10. Muscles
Muscle Actions
Scelta multipla
Which of the following correctly lists the steps of muscle relaxation in order, starting from the cessation of a nerve impulse?
A
Calcium ions are released from the sarcoplasmic reticulum → Acetylcholinesterase breaks down acetylcholine → Troponin and tropomyosin block actin binding sites → Muscle fiber relaxes
B
Acetylcholinesterase breaks down acetylcholine → Calcium ions are pumped back into the sarcoplasmic reticulum → Troponin and tropomyosin block actin binding sites → Muscle fiber relaxes
C
Troponin and tropomyosin block actin binding sites → Acetylcholinesterase breaks down acetylcholine → Calcium ions are pumped back into the sarcoplasmic reticulum → Muscle fiber relaxes
D
Acetylcholine is released into the synaptic cleft → Calcium ions are pumped back into the sarcoplasmic reticulum → Troponin and tropomyosin block actin binding sites → Muscle fiber relaxes
Guida verificata passo dopo passo1
Step 1: Understand the process of muscle relaxation, which begins with the cessation of a nerve impulse. This stops the release of acetylcholine into the synaptic cleft.
Step 2: Acetylcholinesterase, an enzyme, breaks down acetylcholine in the synaptic cleft, preventing further stimulation of the muscle fiber.
Step 3: Calcium ions are pumped back into the sarcoplasmic reticulum via active transport, reducing their concentration in the cytosol.
Step 4: Troponin and tropomyosin return to their resting positions, blocking the binding sites on actin filaments and preventing cross-bridge formation with myosin.
Step 5: With no cross-bridge cycling occurring, the muscle fiber relaxes and returns to its resting state.
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