Final answer:
The sequence of depolarization in the heart's conduction system starts with the SA node, followed by the AV node, the Bundle of His, the right and left bundle branches, and finally the ventricular myocytes.
Step-by-step explanation:
The order in which the cell types depolarize during the spread of an action potential through the conduction system of the heart is as follows:
- SA node
- AV node
- Bundle of His
- Right and left bundle branches
- Ventricular myocytes
This sequence reflects the path of electrical impulses that coordinate the heart's contraction to effectively pump blood. The SA node initiates the action potential, causing the atria to contract. This impulse then travels to the AV node, where there is a short delay to allow the atria to finish contracting and the ventricles to fill with blood. Afterward, the impulse moves through the Bundle of His, down the right and left bundle branches, and lastly, it spreads to the ventricular myocytes, leading to ventricular contraction.