Cardiac m uscle cannot increase its strength of contraction by repetitive stimulation (wave summation) because
A) The action potential lasts hundreds of milliseconds, as long as the cardiac cycle
B) The SR empties its Ca2+ with every heart beat
C) The SA node fires too frequently for the cardiomyocytes to follow
D) The absolute refractory period is longer than the action potential
E) The bundle of His has no reserve capacity
Correct Answer:
Verified
Q2: The force-frequency relation in the heart (the
Q3: Removal of external Ca2+ to levels below
Q4: Stretch increases the force of cardiac contraction
Q5: Cardiomyocytes form a functional syncytium by being
Q6: Relaxation of the cardiomyocytes is caused mainly
Q7: In cardiac muscle, the T-tubules are located
A)
Q8: “Calcium-induced calcium release” refers to
A) Increased Ica
Q9: Cardiac muscle can increase its strength of
Q10: Sympathetic stimulation increases all of the following
Q11: Ca2+ enters the cardiomyocytes every heart beat
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