Question

18. Which one of the following is a matching pair?

1) Lub - sharp closure of AV valves at the beginning of ventricular systole

2) Dub-sudden opening of semilunar valves at the beginning of ventricular diastole

3) Pulsation of the radial artery-valves in the blood vessels

4) Initiation of heart beat-purkinje fibres​

Answer 1

Answer will be (a) Lub - sharp closure of AV valves at the beginning of ventricular systole.

Now lets have a look at other options and understand why those options are wrong :-

Option (b) Dub-sudden opening of semilunar valves at the beginning of ventricular diastole.

Reason : The beating of the heart and the blood flow through it causes the heart sounds. Two types of heart sounds are there lub and dub..

Dub is the second sound of heart which is produced by the closing of semilunar valves at the end of ventricular systole and the beginning of ventricular diastole.

Option (c) Pulsation of the radial artery-valves in the blood vessels

Reason : Radial artery is just a common to measure pulse but it can also be measured at other arteries.

Option (d) Initiation of heart beat-purkinje fibres.

Reason : Heart beat is initiated by SA node (Sinoatrial node).