Which heart structure normally generates spontaneous electrical impulses with the highest intrinsic pacing rate?
Answer and explanation
Correct answer: C. Sinoatrial node located in the right atrial wall
The sinoatrial (SA) node possesses the fastest spontaneous diastolic depolarization rate (60-100 bpm) due to funny currents (If) and acts as the primary cardiac pacemaker. AV node (40-60 bpm) and Purkinje fibers (20-40 bpm) serve as latent backup pacemakers.
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