Final answer:
Vital capacity is the total amount of air that can be expelled from the lungs after taking the deepest breath possible and is the sum of the expiratory reserve volume, tidal volume, and inspiratory reserve volume.
Step-by-step explanation:
The vital capacity (VC) is defined as the total amount of air that can be expelled from the lungs after taking the deepest breath possible. It can be calculated using the following respiratory volumes: expiratory reserve volume (ERV), tidal volume (TV), and inspiratory reserve volume (IRV).
Therefore, the direct answer in 2 lines to this question would be:
- Vital capacity is the sum of the expiratory reserve volume, tidal volume, and inspiratory reserve volume.
The ERV is the extra air you can exhale voluntarily after a normal breath, TV is the air you breathe in and out during normal respiration, and IRV is the additional air you can inhale with effort beyond the normal tidal breath. Adding these volumes together provides the vital capacity, which indicates the total volume of air a person can use during respiratory function. It's crucial for assessing lung health and function. The other options in the question include residual volume, which is the air left in the lungs after maximal expiration and is not a part of vital capacity. Thus, vital capacity does not include residual volume but is a combination of the other three volumes and can be represented by option 'c', expiratory reserve volume + tidal volume + inspiratory reserve volume.