교과서 질문
A newer drug, ivabradine, lowers the heart rate by blocking the nonselective HCN cation channels. Why would this action decrease the heart rate? Would this drug have an effect on pacemaker cells, contractile cells, or both? Explain.
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18. The Heart
Electrical Conduction System of the Heart
Multiple Choice
What occurs during the QRS complex in the electrical conduction system of the heart?
A
Ventricular repolarization
B
Ventricular depolarization
C
Atrial repolarization
D
Atrial depolarization
검증된 단계별 안내1
Understand the components of the ECG: The ECG (electrocardiogram) is a graphical representation of the electrical activity of the heart. It consists of several waves and complexes, including the P wave, QRS complex, and T wave.
Identify the QRS complex: The QRS complex is a specific part of the ECG that represents the rapid depolarization of the ventricles. It is typically the largest and most prominent part of the ECG waveform.
Differentiate between depolarization and repolarization: Depolarization refers to the process by which cardiac muscle cells become electrically activated, leading to contraction. Repolarization is the process by which these cells return to their resting state.
Recognize the role of the QRS complex: During the QRS complex, ventricular depolarization occurs. This is when the electrical impulse travels through the ventricles, causing them to contract and pump blood to the lungs and the rest of the body.
Clarify the other options: Atrial depolarization is represented by the P wave, while atrial repolarization occurs during the QRS complex but is masked by the larger ventricular depolarization signal. Ventricular repolarization is represented by the T wave.
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