Question

Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when
a) ventricular walls vibrate due to gushing in of blood from atria.
b) semilunar valves close down after the blood flows into vessels from vemtricles.
c) AV nodes receives signal from SA node
d) AV valves open up

Answer 1

$\huge\underline{\overline{\mid{\bold{\red{ANSWER}}\mid}}}$

d) AV valves open up

Answer 2

Answer:

the correct answer is option b