AIIMS2008ZoologyBody Fluids and Circulation
Which one of the following is a matching pair?
Options
- ALubb-Sharp closure of AV valves at the beginning of ventricular systole
- BDup-Sudden opening of semilunar valves at the beginning of ventricular diastole
- CPulsation of the radial artery-Valves in the blood vessels
- DInitiation of the heart beat - Purkinje fibres
Correct answer
A. Lubb-Sharp closure of AV valves at the beginning of ventricular systole
Step-by-step solution
Lubb (first sound, systolic sound) is the first heart sound which is low pitched, not very loud, of long duration (about 0.15 seconds) and is produced partly due to closure of atrio-ventricular valves (tricuspid and bicuspid) and partly by the contraction of the muscles in the ventricles.