Question

What is vital capacity of our lungs?

• A. Inspiratory reserve volume plus expiratory reserve volume
• B. Total lung capacity minus residual volume
• C. Inspiratory reserve volume plus tidal volume
• D. Total lung capacity minus expiratory reserve volume

Answer 1

The correct option is B Total lung capacity minus residual volume

Vital capacity is the maximum volume of air a person can inspire after a forced expiration or the maximum volume of air a person can breathe out after a forced inspiration. It is calculated as the sum total of inspiratory reserve volume (IRV), tidal volume (TV), and expiratory reserve volume (ERV), i.e., VC = IRV+TV+ERV. Total lung capacity (TLC) is the sum of vital capacity and residual volume (RV), i.e., TLC = VC+RV. Thus, vital capacity can also be calculated as total lung capacity minus residual volume.