Question

Given that tidal volume is 600ml, inspiratory reserve volume is 2500ml, and expiratory reserve volume is 800ml, what is the value of vital capacity of lungs?
(A) 3900ml
(B) 3300ml
(C) 3100ml
(D) 1400ml

Answer 1

Respiration can be defined as the metabolic process wherein body cells take oxygen and liberates carbon dioxide from oxidation of complex organic compounds and energy is produced. Four standard lung volumes are tidal (TV), expiratory reserve (ERV), inspiratory reserve (IRV), and residual volumes (RV).

Complete answer:
The lung capacity can be defined as the maximum amount of air present in the lung upon maximum inspiration.
The maximum amount of air that can be exhaled or inhaled during a respiratory cycle can be measured as vital capacity (VC).
It is calculated as the sum total of the expiratory reserve volume, inspiratory reserve volume, and tidal volume.
Here given are,
Tidal volume = 600ml
Inspiratory reserve volume = 2500ml
Expiratory reserve volume =800ml
Now, going with options in the question
(A) 3900ml - As we know, the vital capacity of lungs is the sum total of tidal volume, expiratory reserve volume and inspiratory reserve volume.
Also, the sum total of values of given volumes is 3900ml.
(B) 3300ml - The values given in question are not equal to 3300 on summing up as per the definition of vital capacity of lungs.
(C) 3100ml – on summing up the values as per definition of vital capacity of lungs, the answer is not 3100.
(D) 1400ml - This implies the same, that the sum total of above values is not equal to 1400.

Thus, the correct answer is (A)-3900ml.

Note:
After a normal inhalation, the additional amount of air that can be inhaled is inspiratory reserve volume (IRV) and expiratory reserve volume (ERV) is the amount of air that can be exhaled additionally after a normal exhalation.