Vital Capacity is equal to

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding Vital Capacity**:
Vital capacity (VC) is a measure of the maximum amount of air that can be exhaled after a maximum inhalation. It is an important parameter in respiratory physiology.

2. **Components of Vital Capacity**:
Vital capacity is the sum of three different volumes:
- **Tidal Volume (TV)**: This is the amount of air that is inhaled or exhaled during normal breathing. It typically ranges from 500 ml in a healthy adult.
- **Inspiratory Reserve Volume (IRV)**: This is the additional amount of air that can be inhaled after a normal inhalation. It usually ranges from 2500 to 3000 ml.
- **Expiratory Reserve Volume (ERV)**: This is the additional amount of air that can be exhaled after a normal exhalation. It typically ranges from 1000 to 1100 ml.

3. **Formula for Vital Capacity**:
The formula for calculating vital capacity is:
\[ VC = TV + IRV + ERV \]
By substituting the average values, we can estimate the vital capacity.

4. **Calculating Vital Capacity**:
Using the average values:
- TV = 500 ml
- IRV = 2500 ml
- ERV = 1000 ml
Therefore:
\[ VC = 500 \, \text{ml} + 2500 \, \text{ml} + 1000 \, \text{ml} = 4000 \, \text{ml} \]
This means the vital capacity is approximately 4000 ml for a healthy adult.

5. **Conclusion**:
Based on the definition and components, the correct answer to the question "Vital Capacity is equal to" is the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume.

**Final Answer**: Vital Capacity = Tidal Volume + Inspiratory Reserve Volume + Expiratory Reserve Volume.

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