Anonymous
Anonymous asked in HealthDiseases & ConditionsCancer · 1 decade ago

An individual has just ingested a chemical that binds irreversibly to the ACh receptors in the sarcolemma. By.?

An individual has just ingested a chemical that binds irreversibly to the ACh receptors in the sarcolemma. By itself it does not alter membrane potential, yet prevents normal neurotransmitter binding. Ignoring the effects on any other system, the consequence to skeletal muscle would be....

A.) irreversible contraction as soon as the first nervous stimulation reached the sarcolemma

B.) no contraction at all by nervous mechanism

C.) contraction if stimulated by an external electrode

D.) no contraction at all by nervous mechanism, but contraction if stimulated by an external electrode

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  • anna
    Lv 6
    1 decade ago
    Favorite Answer

    d.-

    if you can, by an external pulse of energy change the membrane potential so the calcium channels would open, the muscle would still be able to contract, cause the contraction mecanism aren't affected, what's affected is the trigger that starts it all (Ach binding to the receptor).-

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  • 1 decade ago

    D final answer. Ach stimulates calcium release into the t-tubules, initiating muscle contraction. No Ach binding, no contraction. But, e-stim doesn't rely on neurotransmitters like Ach so it'll still work.

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  • 1 decade ago

    D

    As said above. This is actually how the poison Curare works, by blocking the AchR.

    See here:

    http://www.frca.co.uk/article.aspx?articleid=236

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