The correct arrangement of events in the cardiac cycle according to their duration is :

Options

A. Atrial systole - Ventricular systole -Ventricular diastole - Atrial diastole
B. Atrial systole - Ventricular systole - Atrial diastole - Ventricular diastole
C. Atrial systole - Atrial diastole -Ventricular systole - Ventricular diastole
D. Ventricular systole - Atrial systole - Ventricular diastole -Atrial diastole

Answer

To solve the question regarding the correct arrangement of events in the cardiac cycle according to their duration, we will analyze the different phases of the cardiac cycle and their respective durations.

### Step-by-Step Solution:

1. **Understanding the Cardiac Cycle**: The cardiac cycle consists of a series of events that occur during one heartbeat. It includes phases of contraction (systole) and relaxation (diastole) of the heart chambers.

2. **Identifying the Phases**:
- **Atrial Systole**: This is the contraction of the atria, which lasts approximately 0.1 seconds.
- **Ventricular Systole**: This is the contraction of the ventricles, lasting about 0.3 seconds.
- **Ventricular Diastole**: This is the relaxation of the ventricles, which takes about 0.5 seconds.
- **Atrial Diastole**: This is the relaxation of the atria, which occurs simultaneously with ventricular diastole.

3. **Duration of the Cardiac Cycle**: The total duration of the cardiac cycle is approximately 0.8 seconds, which is the sum of the durations of all phases.

4. **Arranging the Phases by Duration**:
- From the durations provided:
- Atrial Systole (0.1s)
- Ventricular Systole (0.3s)
- Ventricular Diastole (0.5s)
- Atrial Diastole (part of the overall diastole, but not specifically measured)

5. **Correct Arrangement**: Based on the durations:
- The correct order is:
- Atrial Systole (0.1s)
- Ventricular Systole (0.3s)
- Ventricular Diastole (0.5s)
- Atrial Diastole (part of the overall diastole)

6. **Conclusion**: The correct arrangement of events in the cardiac cycle according to their duration is:
- **Atrial Systole → Ventricular Systole → Ventricular Diastole → Atrial Diastole**.

### Final Answer:
The correct arrangement of events in the cardiac cycle according to their duration is **Option 1**: Atrial Systole, Ventricular Systole, Ventricular Diastole, and Atrial Diastole.