Which is the correct full sequence of major conduction structures from atria to ventricles?

Which is the correct full sequence of major conduction structures from atria to ventricles?

• A. SAN, AVN, His bundle, Bundle branches, Purkinje fibers, ventricular myocardium
• B. AVN, SAN, His bundle, Purkinje fibers, Bundle branches, ventricular myocardium
• C. SAN, His bundle, AVN, Purkinje fibers, Bundle branches, ventricular myocardium
• D. SAN, AVN, Purkinje fibers, His bundle, Bundle branches, ventricular myocardium

Answer: (A)

Understanding the orderly conduction pathway from atria to ventricles is essential to grasp how the heart coordinates timing of contraction. The impulse starts in the sinoatrial node, the heart’s natural pacemaker in the right atrium. It then spreads through the atrial myocardium and reaches the atrioventricular node, where a deliberate delay slows conduction to give the ventricles time to fill. From the AV node, the signal travels into the His bundle, then down the bundle branches within the interventricular septum, and finally reaches the Purkinje fiber network that rapidly distributes the impulse to the ventricular myocardium, triggering coordinated ventricular contraction. Sequences that place the AV node before the SA node or that put Purkinje fibers before the bundle branches don’t reflect how the impulse actually travels through the heart.

Understanding the orderly conduction pathway from atria to ventricles is essential to grasp how the heart coordinates timing of contraction. The impulse starts in the sinoatrial node, the heart’s natural pacemaker in the right atrium. It then spreads through the atrial myocardium and reaches the atrioventricular node, where a deliberate delay slows conduction to give the ventricles time to fill. From the AV node, the signal travels into the His bundle, then down the bundle branches within the interventricular septum, and finally reaches the Purkinje fiber network that rapidly distributes the impulse to the ventricular myocardium, triggering coordinated ventricular contraction. Sequences that place the AV node before the SA node or that put Purkinje fibers before the bundle branches don’t reflect how the impulse actually travels through the heart.