Which of the following is the correct ascending order of all pulmonary volumes ?

Options

A. `TV lt RV lt IRV lt ERV`
B. `TV lt ERV lt RV lt IRV`
C. `TV lt RV lt IRV lt ERV`
D. `IRV gt ERV gt RV gt TV`

Answer

To determine the correct ascending order of all pulmonary volumes, we need to understand the definitions and average values of the four main types of pulmonary volumes:

1. **Tidal Volume (TV)**: This is the amount of air inhaled or exhaled during a normal breathing cycle. The average volume is approximately **500 ml**.

2. **Expiratory Reserve Volume (ERV)**: This is the amount of air that can be forcibly exhaled after a normal exhalation. The average volume is about **1200 ml** for men and **700 ml** for women. For our purposes, we will consider the higher value of **1200 ml**.

3. **Residual Volume (RV)**: This is the amount of air remaining in the lungs after a maximal exhalation. The average volume is about **1200 ml** for both men and women.

4. **Inspiratory Reserve Volume (IRV)**: This is the amount of air that can be forcibly inhaled after a normal inhalation. The average volume is about **3000 ml** for men and **2000 ml** for women. Again, we will consider the higher value of **3000 ml**.

Now, let's arrange these volumes in ascending order based on their average values:

- **Tidal Volume (TV)**: 500 ml
- **Expiratory Reserve Volume (ERV)**: 1200 ml
- **Residual Volume (RV)**: 1200 ml
- **Inspiratory Reserve Volume (IRV)**: 3000 ml

Since ERV and RV have the same average value, we can place them together in the order.

Thus, the correct ascending order of all pulmonary volumes is:

**Tidal Volume < Expiratory Reserve Volume = Residual Volume < Inspiratory Reserve Volume**

### Final Answer:
**Tidal Volume < Expiratory Reserve Volume = Residual Volume < Inspiratory Reserve Volume**