Toward the end of systole, as repolarization starts (indicated by the T wave), the ventricles begin to relax. Which of the following will occur next?
a. Rapid rise in ventricular pressures.
b. Arterial pressures exceed ventricular pres-sures.
c. Closure of the atrioventricular valves.
d. Opening of semilunar valves.
ANS: B
Toward the end of systole, as repolarization starts (indicated by the T wave), the ventricles begin to relax. Consequently, ventricular pressures drop rapidly. When arterial pressures exceed those in the relaxing ventricles, the semilunar valves shut.
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