[Campbell Biology P.977] Which of the following sequences correctly describes the path of el... | Practice Question

Which of the following sequences correctly describes the path of electrical impulses through the heart during a normal heartbeat, starting from the primary pacemaker?

  • A: SA node → AV node → Bundle branches → Purkinje fibers → Ventricular walls
  • B: SA node → Atria → AV node → Bundle branches → Purkinje fibers → Ventricular walls
  • C: AV node → SA node → Atria → Bundle branches → Purkinje fibers → Ventricular walls
  • D: SA node → Atria → Purkinje fibers → Bundle branches → Ventricular walls

Explanation

The electrical impulses originate in the SA node, spread through the atria, are delayed at the AV node, then pass to the bundle branches, which conduct them to the heart apex and then throughout the ventricular walls via Purkinje fibers. This sequence is explicitly described in the text and illustrated in Figure 42.8.