Vital capacity of lungs includes :

Options

A. IRV + TV + ERV
B. ERV + RV
C. IRV + TR
D. RV+ ERV + TV + IRV

Answer

To answer the question about what the vital capacity of the lungs includes, we can break it down step by step.

### Step-by-Step Solution:

1. **Understanding Vital Capacity**:
- Vital capacity (VC) is defined as the maximum amount of air a person can exhale after taking the deepest possible inhalation.

2. **Components of Vital Capacity**:
- Vital capacity is the sum of three specific lung volumes:
- **Inspiratory Reserve Volume (IRV)**: The amount of air that can be inhaled after a normal inhalation.
- **Tidal Volume (TV)**: The amount of air that is inhaled or exhaled during normal breathing.
- **Expiratory Reserve Volume (ERV)**: The amount of air that can be forcibly exhaled after the end of a normal expiration.

3. **Mathematical Representation**:
- The formula for vital capacity can be expressed as:
\[ VC = IRV + TV + ERV \]

4. **Evaluating Options**:
- Now, let's evaluate the given options:
- **Option 1**: IRV + TV + ERV - This is correct as it matches the definition of vital capacity.
- **Option 2**: ERV + RV - This is incorrect because it does not include IRV or TV.
- **Option 3**: IRV + TV - This is incorrect as it does not include ERV.
- **Option 4**: RV + ERV + TV + IRV - This is incorrect because it includes Residual Volume (RV), which is not part of vital capacity.

5. **Conclusion**:
- The correct answer is **Option 1: IRV + TV + ERV**.