MCAT Question of the Day
    •

    Q:

    		 Cardiac contraction is chemically caused by
    		 

    A

    		 Changes in intracellular sodium concentration

    B

    		 Changes in intracellular calcium concentration

    C

    		 Interactions of potassium with contractile tubules

    D

    		 None of the above



    Circulatory System |
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