What is the electrical pathway of the heart, in order? NOTE - this includes pacemaker and conduction components.

a) SA node, internodal pathways, AV node, bundle of His, bundle branches

b) SA node, internodal pathways, AV node, bundle branches, bundle of His

c) AV node, internodal pathways, SA node, bundle of His, bundle branches

d) AV node, internodal pathways, SA node, bundle of His, bundle branches

The correct answer will be option A.

Explanation:

The electrical impulses are generated in the sino-atrial node or SA node, a mass of cells which generates impulse in the upper atrium.

This electrical impulse transmits from the sino-atrial node to the atrio-ventricular node in the lower portion of the upper atrium through the internodal pathway - the pathway composed of atrial cells.

Once the impulse reaches the AV node, it is transferred to the ventricular portion of the heart through Bundle of His presence in the ventricular septum. This bundle of his divides into left and right ventricles through bundle branches and stimulates both the ventricles.

Thus, option-A is the correct answer.