Question
Which one of the following is a matching pair
Lubb - Sharp closure of AV valves at the beginning of ventricular systole
Dup - Sudden opening of semilunar valves at the beginning of ventricular diastole
Pulsation of the radial artery - Valves in the blood vessels
Initiation of the heart beat - Purkinje fibres
Solution
A.
Lubb - Sharp closure of AV valves at the beginning of ventricular systole
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 atria-ventricular valves (tricuspid and bicuspid) and partly by the contraction of the muscles in the ventricles
