| (a) | |
| IRV | ERV |
| The additional volume of air, which a person can forcibly inspire, is called inspiratory reserve volume. | The additional volume of air, which a person can forcibly expire, is called expiratory reserve volume. |
| (b) | |
| Inspiratory capacity | Expiratory capacity |
| Total volume of air a person can inspire after a normal expiration. | Total volume of air a person can expire after a normal inspiration. |
| This includes tidal volume and inspiratory reserve volume (TV + IRV). | This includes tidal volume and expiratory reserve volume (TV + ERV). |
| (c) | |
| Vital capacity | Total lung capacity |
| The maximum volume of air a person can breathe in after a forced expiration. | Total volume of air accommodated in the lungs at the end of a forced inspiration. |
| This includes ERV, TV and IRV or the maximum volume of air a person can breathe out after a forced inspiration. | This includes RV, ERV, TV and IRV or vital capacity + residual volume. |