Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound is heard when:
A.
Ventricular wall vibrate due to gushing in of blood from atria
B.
Semilunar valves close down after the blood flows into vessels from ventricles
C.
AV node receives signal from SA node
D.
AV valves open up
Answer :
Semilunar valves close down after the blood flows into vessels from ventricles
Releted MCQ Question on Zoology >> Body Fluids and Circulation
Releted Question 1
Adult human RBCs are enucleated. Which of the following statement(s) is/are most appropriate explanation for this feature? (1) They do not need to reproduce (2) They are somatic cells (3) They do not metabolize (4) All their internal space is available for oxygen transport