Question

The problem of electrical discontinuity caused in the normal heart by the connective tissue separating the atria from the ventricles is solved by ?

• A. Coordinating electrical activity in the atria with electrical activity in the ventricles by connecting them via the bundle of His
• B. Having the A-V node function as a secondary pacemaker
• C. Having an ectopic pacemaker
• D. Coordinating electrical activity in the atria with electrical activity in the ventricles by connecting them via the vagus nerve.

Answer 1

The correct option is B Having the A-V node function as a secondary pacemaker

B. Having the A-V node function as a secondary pacemaker

Reason: A-V node functions as a secondary pacemaker because when the wave of contraction originating from the sinoatrial node reaches the atrioventricular node (AV node – pace setter), the latter is stimulated and excitatory impulses are rapidly transmitted from it to all parts of the ventricles to contract simultaneously. The ventricles force blood through long system of arteries and hence must exert great pressure on the blood.