Q. Which one of the following statements is correct?
A) Increased ventricular pressure causes closing of the semilunar valves
B) The atrio-ventricular node (AVN) generates an action potential to stimulate atrial contraction
C) The tricuspid and the bicuspid valves open due to the pressure exerted by the simultaneous contraction of the atria
D) Blood moves freely from atrium to the ventricle during joint diastole.
Explanation
[Solution] During joint diastole the AV valves are open and blood flows freely from atria to ventricles. Increased ventricular pressure opens semilunar valves, and the SAN (not AVN) initiates atrial contraction. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.