Question

Which of the following is the correct sequence of cardiac electrical activity?

1. AV node
2. Internodal pathways
3. Bundle of His
4. SA node
5. Purkinje fibers
6. Bundle branches

A) 1, 2, 4, 3, 6, 5

B) 4, 1, 2, 3, 6, 5

C) 1, 2, 4, 3, 5, 6

D) 4, 2, 1, 3, 6, 5

Answer 1

The correct sequence of cardiac electrical activity starts at the SA node, proceeds through internodal pathways to the AV node, then to the Bundle of His, followed by the bundle branches, and ends with the Purkinje fibers, indicating option D as the correct sequence.

Step-by-step explanation:

The correct sequence of cardiac electrical activity is as follows: The sinoatrial (SA) node initiates the action potential, which sweeps across the atria. This impulse travels through specialized internodal pathways to the atrioventricular (AV) node, where there is a delay allowing the atria to finish pumping blood. After this delay, the impulse travels to the atrioventricular bundle (Bundle of His), then into the right and left bundle branches which extend through the interventricular septum, and finally to the Purkinje fibers, spreading the impulse throughout the ventricles, leading to ventricular contraction.

The correct sequence of cardiac electrical activity that you asked about is therefore represented by option D) 4, 2, 1, 3, 6, 5.