Why is the electrical impulse temporarily delayed at the atrioventricular (AV) node?
a. To allow complete emptying of the ventri-cles
b. To allow more sodium buildup in the my-ocardial cells
c. To allow better filling of the ventricles
d. To allow complete filling of the atria
ANS: C
The impulse is temporarily delayed at the AV node in order to allow the ventricles time to fill with blood. That brief delay also limits the rate of the ventricular stimulation during excessively fast atrial rhythms that, if passed to the ventricles, would lead to inadequate cardiac output.
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