Final answer:
The QRS complex on an ECG represents the conduction of the electrical impulse through both ventricles, reflecting ventricular depolarization essential for contraction and blood pumping.
Step-by-step explanation:
The conduction of the electrical impulse through both ventricles appears on an ECG tracing as the QRS complex. The QRS complex is a crucial component of a normal electrocardiogram (ECG), reflecting the process of ventricular depolarization. The sequence of an ECG comprises several waves and complexes, including the P wave, which signifies atrial depolarization, and the subsequent atrial contraction.
Following this, the QRS complex indicates the depolarization of the ventricles, which is essential for ventricular contraction and precedes the pumping of blood to the lungs and body. The R wave, the peak of this complex, is the point at which the ventricles begin to contract. Lastly, the T wave shows ventricular repolarization, symbolizing the beginning of ventricular relaxation before the next cycle begins. The atrial repolarization occurs simultaneously with the QRS complex but is not visible on the ECG as it is masked by the larger electrical activity of the ventricles.