Question

Which of the following represents the correct sequence of the origin and conduction of action potential?

• A. SA node → AV node → Bundle of His → Purkinje fibers
• B. AV node → SA node → Bundle of His → Purkinje fibers
• C. SA node → AV node → Purkinje fibers → Bundle of His
• D. Bundle of His → Purkinje fibers → SA node → AV node

Answer 1

The correct option is A

SA node → AV node → Bundle of His → Purkinje fibers

The correct option is A

Explanation for the correct option:

1. The SA Node, which is situated on the superior, posterolateral wall of the right atrium, starts the cardiac action potential.
2. The Interatrial Band, which facilitates in quick transmission of the action potential from the right to the left atrium, and contractile atrial cardiomyocytes all share a direct connection to the SA Node.
3. The AV Node, which lies right above a small passage through the cardiac fibrous skeleton connecting the atria and the ventricular myocardial tissue, receives the cardiac action potential via this manner.
4. The propagation of the action potential from the atria to the ventricles is considerably delayed as a result of the AV Nodal cells' extremely slow conductivity of cardiac action potentials.
5. The ventricular action potential is transmitted through both ventricles via swiftly moving conducting cardiomyocytes linked to the inferior AV Node, also known as the Purkinje Fibers.
6. The first group of Purkinje fibers to become active is found in the interventricular septum, where it is organized into bundles called the bundles of His.
7. These leave the fibrous canal in the Right and Left bundles and go via the interventricular septum to the apex of the heart along the outside walls of both ventricles.

Final answer: SA node → AV node → Bundle of His → Purkinje fibers represent the correct sequence of the origin and conduction of action potential.