Question

Vital capacity (VC) of lungs is_____________________

• A. 1500ml
• B. 2000ml
• C. 2300ml
• D. 4300ml

Answer 1

The correct option is D 4300ml

Vital capacity is defined as the maximum volume of air that can be breathed in after a forceful expiration or it can also be defined as the maximum volume of air that can be breathed out after a forceful inspiration. Vital capacity (VC) is the sum of expiratory reserve volume (ERV), tidal volume (TV), and inspiratory reserve volume (IRV).
The tidal volume(TV) is the volume of air that is taken in and out of the lungs during normal breathing.
Expiratory reserve volume (ERV) is the volume of air that is exhaled forcefully after normal exhalation.
Inspiratory reserve volume (IRV) is the volume of air that is inhaled forcefully after a normal inhalation.

VC = ERV+TV+IRV
The value of the tidal volume is 500ml.
The value of expiratory reserve volume is around 1000ml to 1100ml. Considering the average of the maximum and the minimum value, it is 1050ml.
Similarly, the value of inspiratory reserve volume is around 2500ml to 3000ml. Considering the average of the maximum and the minimum value, it is 2750ml.
So, VC=500ml+ 1050ml+ 2750ml
=4300ml.