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 each pulmonary volume. Here’s a step-by-step breakdown:

### Step 1: Define the Pulmonary Volumes
1. **Tidal Volume (TV)**: This is the volume of air inspired or expired during normal respiration. The average value is approximately **500 ml**.

2. **Inspiratory Reserve Volume (IRV)**: This is the additional volume of air that can be inspired with a forcible inspiration after a normal inhalation. The average value is around **2500 ml to 3000 ml**.

3. **Expiratory Reserve Volume (ERV)**: This is the additional volume of air that can be expelled from the lungs after a normal expiration. The average value is approximately **1000 ml to 1100 ml**.

4. **Residual Volume (RV)**: This is the volume of air that remains in the lungs even after a forcible expiration. The average value is about **1100 ml to 1200 ml**.

### Step 2: List the Volumes with Their Values
- Tidal Volume (TV) = **500 ml**
- Expiratory Reserve Volume (ERV) = **1000 ml to 1100 ml**
- Residual Volume (RV) = **1100 ml to 1200 ml**
- Inspiratory Reserve Volume (IRV) = **2500 ml to 3000 ml**

### Step 3: Arrange in Ascending Order
Now, we can arrange these volumes in ascending order based on their average values:
1. **Tidal Volume (TV)**: 500 ml
2. **Expiratory Reserve Volume (ERV)**: 1000 ml to 1100 ml
3. **Residual Volume (RV)**: 1100 ml to 1200 ml
4. **Inspiratory Reserve Volume (IRV)**: 2500 ml to 3000 ml

### Step 4: Final Answer
The correct ascending order of all pulmonary volumes is:
**Tidal Volume < Expiratory Reserve Volume < Residual Volume < Inspiratory Reserve Volume**