In a standard ECG which one of the following alphabets is the correct representation of the respective activity of the human heart ?

Options

A. T-end of diastole
B. P-depolarizatio of the atria
C. R-repolarisation of ventricles
D. S-start of systole

Explanation

To answer the question regarding the correct representation of the respective activity of the human heart in a standard ECG, we will analyze the components of the ECG and their meanings step by step.

### Step-by-Step Solution:

1. **Understanding ECG**:
- The ECG (electrocardiogram) records the electrical activity of the heart. It shows how the heart muscles contract and relax during the cardiac cycle.

2. **Identifying the Waves**:
- The ECG consists of several waves: P wave, QRS complex, and T wave.
- Each wave corresponds to specific electrical activities in the heart.

3. **P Wave**:
- The P wave represents the depolarization of the atria, which is the contraction of the atrial muscles. This is the first wave seen in the ECG.

4. **QRS Complex**:
- The QRS complex represents the depolarization of the ventricles, indicating the contraction of the ventricular muscles. It occurs after the P wave.

5. **T Wave**:
- The T wave represents the repolarization of the ventricles, indicating the relaxation of the ventricular muscles after contraction.

6. **Analyzing the Options**:
- Option 1: T is the end of the diastole - This is incorrect because the T wave indicates ventricular relaxation, not the end of diastole.
- Option 2: P wave is the depolarization of the atria - This is correct as the P wave shows atrial contraction.
- Option 3: R wave is the repolarization of the ventricles - This is incorrect; the T wave represents repolarization, not the R wave.
- Option 4: S starts of the systole - This is incorrect; the Q wave marks the beginning of systole, not the S wave.

7. **Conclusion**:
- The correct answer is **Option 2**, which states that the P wave represents the depolarization of the atria.