What is the role of calcium in Excitation-contraction coupling of the heart?

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  • Ted K
    Lv 7
    1 month ago

    Ultimately the same as its role in skeletal muscle contraction--calcium binds to troponin-C.  That binding acts to pull tropomyosin out of the way of the myosin binding site on actin, allowing actin-myosin crossbridges to form.

    Ca2+ has one other key role in cardiac EC-coupling--extracellular Ca2+ entering the myocyte triggers opening of sarcoplasmic calcium release channels (the so-called ryanodine receptor), in a process referred to as calcium-induced calcium release.

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