Explain the reason there is a delay in processing the electrical signal from the AV node to the AV bundle. To:
1. allow the atria to complete their contraction prior to ventricular contraction
2. ensure the right and left atria contract at the same time
3. ensure the right and left ventricles contract at the same time
4 prevent an ectopic pacemaker
Which one of the following is a matching pair?
1. Lubb sharp closure of AV valves at the beginning of ventricular systole
2. Dup - 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 the heart beat Purkinje fibres