Which conducting tissue extends from the AV bundle to the ventricular walls to coordinate ventricular contraction?

Which conducting tissue extends from the AV bundle to the ventricular walls to coordinate ventricular contraction?

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

Answer: (A)

Coordinated ventricular contraction relies on a fast, widespread network that delivers impulses quickly to the entire ventricular muscle. Purkinje fibers form the terminal part of the His-Purkinje system, extending from the bundle branches—which originate from the AV bundle—into the ventricular walls. Their high conduction speed allows the impulse to reach all parts of the ventricles nearly simultaneously, producing a synchronized and forceful contraction. The other parts of the conduction system have different roles: the SA node sets the heart rate, the AV node introduces a brief delay to allow ventricular filling, and the bundle of His carries impulses from the AV node toward the ventricles but does not disseminate them through the ventricular walls as the Purkinje fibers do.

Coordinated ventricular contraction relies on a fast, widespread network that delivers impulses quickly to the entire ventricular muscle. Purkinje fibers form the terminal part of the His-Purkinje system, extending from the bundle branches—which originate from the AV bundle—into the ventricular walls. Their high conduction speed allows the impulse to reach all parts of the ventricles nearly simultaneously, producing a synchronized and forceful contraction. The other parts of the conduction system have different roles: the SA node sets the heart rate, the AV node introduces a brief delay to allow ventricular filling, and the bundle of His carries impulses from the AV node toward the ventricles but does not disseminate them through the ventricular walls as the Purkinje fibers do.