Duration between first and second heart sound is nearly equal to duration of

Options

A. Atrial systole
B. Atrial diastole
C. ventricular systole
D. ventricular diastole

Answer

To solve the question regarding the duration between the first and second heart sounds, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Heart Sounds**: The first heart sound (S1) is known as "lub," and the second heart sound (S2) is known as "dub." The duration between these two sounds is significant in understanding the cardiac cycle.

2. **Duration of Heart Sounds**: The duration between the first and second heart sounds is approximately 0.3 seconds. This is crucial for comparing it with the durations of other phases of the cardiac cycle.

3. **Evaluate Options**:
- **Option 1: Arterial Systole**: This phase lasts about 0.1 seconds. Since 0.1 seconds is much shorter than 0.3 seconds, this option is incorrect.
- **Option 2: Arterial Diastole**: This phase lasts about 0.7 seconds. Since 0.7 seconds is longer than 0.3 seconds, this option is also incorrect.
- **Option 3: Ventricular Systole**: This phase is associated with the contraction of the ventricles and lasts about 0.3 seconds. This matches the duration of the interval between the first and second heart sounds, making this option correct.
- **Option 4: Ventricular Diastole**: This phase lasts about 0.5 seconds, which is longer than 0.3 seconds, thus this option is incorrect.

4. **Conclusion**: Based on the evaluation, the duration between the first and second heart sounds is nearly equal to the duration of the **ventricular systole**, which is approximately 0.3 seconds.

### Final Answer:
The duration between the first and second heart sounds is nearly equal to the duration of **ventricular systole**.

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