Question

The sequence of conduction in human heart may be

• A. SA-node, bundle of His, Purkinje fibres AV-node, heart muscle
• B. SA-node, AV-node, Purkinje fibres, bundle of His, heart muscle
• C. SA-node, AV-node, bundle of His, Purkinje fibres, heart muscle
• D. none of these

Answer 1

Answer: (C)

The SA node (sino-atrial node) is the original pacemaker. It initiates the cardiac impulse. It then flows on to the AV node present in the wall of the right atrium. From there the impulse is carried by the atrioventricular bundle or the Bundle of His through the atrioventricular septum and then the Purkinje fibres spread it through the two ventricles. The pulse making impulse travels in the heart in the following order:
SA node $\to$ AV node $\to$ bundle of His $\to$ Purkinje fibres $\to$ heart muscles.