The largest quantity of air that can be exhaled after a maximal inspiratory effort is :

Options

A. vital capacity
B. tidal volume
C. residual volume
D. total lung capacity

Explanation

To determine the largest quantity of air that can be exhaled after a maximal inspiratory effort, we need to understand the different lung volumes and capacities involved in the respiratory process. Here’s a step-by-step breakdown:

### Step 1: Understand Lung Volumes
The respiratory system has several key volumes:
- **Tidal Volume (TV)**: The amount of air inhaled or exhaled during normal breathing, approximately 500 ml.
- **Inspiratory Reserve Volume (IRV)**: The additional air that can be inhaled after a normal inhalation, typically around 2500-3000 ml.
- **Expiratory Reserve Volume (ERV)**: The additional air that can be exhaled after a normal exhalation, about 1000-1100 ml.
- **Residual Volume (RV)**: The amount of air that remains in the lungs after a maximal exhalation, approximately 1100-1200 ml.

### Step 2: Define Vital Capacity
The **Vital Capacity (VC)** is defined as the maximum amount of air that can be exhaled after a maximal inhalation. It is the sum of:
- Tidal Volume (TV)
- Inspiratory Reserve Volume (IRV)
- Expiratory Reserve Volume (ERV)

### Step 3: Calculate Vital Capacity
To find the vital capacity, we add the volumes together:
\[ VC = TV + IRV + ERV \]
Substituting the average values:
\[ VC = 500 \, \text{ml} + 2500 \, \text{ml} + 1000 \, \text{ml} \]
\[ VC = 4000 \, \text{ml} \]

### Step 4: Conclusion
The largest quantity of air that can be exhaled after a maximal inspiratory effort is the **Vital Capacity (VC)**, which is approximately 4000 ml for an average adult.