Doctors use a stethoscope to hear the sounds produced during each cardiac cycle. The second heart sound is heard when:

  • A
    $AV$ node receives a signal from the $SA$ node
  • B
    $AV$ valves open up
  • C
    Ventricular walls vibrate due to the gushing in of blood from the atria
  • D
    Semilunar valves close down after the blood flows into vessels from the ventricles

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Similar Questions

What is the contraction of the heart called?

Time interval between the closure of semilunar valve and closure of $AV$ valve is (in $; s$)

Define a cardiac cycle and the cardiac output.

The first heart sound '$Lubb$' occurs in which phase of the cardiac cycle?

What do diagrams $A, B$ and $C$ indicate?
Choose the correct combination.

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