Which of the following correctly lists the main components of the cardiac conduction system in the order that an electrical impulse travels through the heart?

• A. Atrioventricular node, sinoatrial node, Purkinje fibers, bundle branches, bundle of His
• B. Purkinje fibers, bundle branches, bundle of His, atrioventricular node, sinoatrial node
• C. Bundle of His, sinoatrial node, atrioventricular node, Purkinje fibers, bundle branches
• D. Sinoatrial node, atrioventricular node, bundle of His, bundle branches, Purkinje fibers

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the cardiac conduction system, which is responsible for initiating and propagating electrical impulses that control the heart's rhythm and contraction.
2. Step 2: Identify the main components of the cardiac conduction system: the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, bundle branches, and Purkinje fibers.
3. Step 3: Recognize the sequence of electrical impulse travel: The impulse begins at the sinoatrial (SA) node, which is the natural pacemaker of the heart, located in the right atrium.
4. Step 4: The impulse then travels to the atrioventricular (AV) node, which delays the signal slightly to allow the atria to contract and fill the ventricles with blood.
5. Step 5: From the AV node, the impulse moves to the bundle of His, then splits into the bundle branches, and finally reaches the Purkinje fibers, which distribute the signal throughout the ventricles to ensure coordinated contraction.