Question

Which of the following is the correct conduction pathway through the heart?

A) Purkinje fibers; bundle of His; bundle branches; SA node; AV node
B) SA node; AV node; bundle of His; bundle branches; Purkinje fibers
C) AV node; SA node; bundle branches; bundle of His; Purkinje fibers
D) Bundle of His; bundle branches; Purkinje fibers; SA node; AV node
E) SA node; Purkinje fibers; AV node; bundle of His; bundle branches

Answer 1

The sequence that correctly describes the conduction pathway through the heart is: SA node, AV node, bundle of His, bundle branches, Purkinje fibers. This pathway allows for coordinated contraction of the heart muscles. The AV node has the slowest rate of firing in the heart conduction system.

Step-by-step explanation:

The correct conduction pathway through the heart is the one that starts with the sinoatrial node (SA node), then moves to the atrioventricular node (AV node), proceeds to the atrioventricular bundle (bundle of His), continues down the bundle branches, and finally, ends with the Purkinje fibers.

Based on this pathway:

1. The SA node initiates the action potential, causing the atria to contract.
2. Then, the impulse reaches the AV node, where it pauses briefly.
3. Following the delay, the action potential is transmitted to the atrioventricular bundle.
4. It then travels down the left and right bundle branches.
5. Finally, the impulse is conducted by the Purkinje fibers to the contractile fibers of the ventricles, resulting in ventricular contraction.

This process ensures that the atria have time to empty their contents into the ventricles before ventricular contraction occurs. As for the question of which component of the heart conduction system has the slowest rate of firing, that would be the atrioventricular node.