Q. Which one of the following is matching pair?
A) Lubb $-$ Sharp closure of AV valves at the beginning of ventricular systole
B) Dup $-$ Sudden opening of semilunar valves at the beginning of ventricular diastole
C) Pulsation of the $-$ Valves in the blood vessels radial artery
D) Initiation of the heart beat $-$ Purkinje fibres
Explanation
First sound of heart is lubb (a long and booming sound), created by the closure of atrio-ventricular valve (AV), tricuspid and bicuspid at the beginning of ventricular systole. At the beginning of ventricular diastole, the semilunar valves close, producing the second sound ‘dup’.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.