QRS complex represents the -

Options

A. Depolarization of ventricles
B. Repolarization of ventricles
C. Repolarization of atria
D. Depolarization of atria

Answer

**Step-by-Step Solution:**

1. **Understanding the Electrocardiogram (ECG):** The electrocardiogram (ECG) is a graphical representation of the electrical activity of the heart over time. It consists of several components, including the P wave, QRS complex, and T wave.

2. **Identifying the QRS Complex:** The QRS complex is a specific part of the ECG waveform. It follows the P wave and precedes the T wave. The QRS complex is typically characterized by three distinct waves: the Q wave, R wave, and S wave.

3. **Function of the QRS Complex:** The primary function of the QRS complex is to represent the depolarization of the ventricles. Depolarization is the process by which the heart muscle cells become electrically activated, leading to contraction.

4. **Ventricular Systole:** The depolarization of the ventricles, indicated by the QRS complex, corresponds to what is known as ventricular systole. This is the phase of the cardiac cycle during which the ventricles contract.

5. **Blood Pumping Action:** During ventricular systole, the contraction of the ventricles pumps blood out of the heart. The left ventricle pumps blood into the aorta (dorsal aorta), while the right ventricle pumps blood into the pulmonary artery.

**Final Answer:** The QRS complex represents the depolarization of the ventricles, which is associated with ventricular systole (ventricular contraction) and the pumping of blood from the heart.

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