Which is true about heart sound?
Ans. B First heart sound has maximum durationHeart soundFrequencyDurationAssociated eventFirst heart25-45 Hz0.15 secClosure of A-V valves--onset of ventricular systoleSecond heart sound50 Hz0.12 secClosure of semilunar valves--onset of ventricular diastoleThird heart soundLow0.1 secFirst rapid filling phase of ventricular diastoleFourth heart soundBelow 20 Hz0.1 secLast rapid filling phase of ventricular diastole due to atrial contraction
First heart sound has maximum frequency
First heart sound has maximum duration
First heart sound is due to semilunar valve closure
Second heart sound is due to AV valve closure
Heart, Circulation, and Blood