Question

After forceful inspiration, the amount of air that can be breathed out by maximum forced expiration is equal to
A) Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV) + Tidal Volume (TV) + Residual Volume (RV)
B) IRV + RV + ERV
C) IRV +TV + ERV
D) TV + RV + ERV

Answer 1

Inspiration is the process of inhaling the air. During forceful inspiration, the lungs are filled to their maximum capacity by a little bit of force. On the other hand, expiration is the process of exhaling out of the air by the lungs.

Complete answer: There are different types of lung capacities; they are
a) The TV or Tidal volume is the normal amount of air that we can inspire or expire. The tidal volume of the lungs is 500 ml.
b) The IRV or Inspiratory reserve volume is the amount of air that is inspired forcefully. The inspiratory reserve volume of the lungs is 3000 ml.
c) The ERV or Expiratory reserve volume is the amount of air that is expired forcefully without inspiration. The expiratory reserve volume of the lungs is 1100 ml.
d) The VC or Vital capacity is the total amount of forceful air that is expired after forceful inspiration. It is defined as the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume. The vital capacity of the lungs is 4600 ml. Thus, based on the above information we can conclude that after forceful inspiration, the amount of air that can be breathed out by maximum forced expiration is equal to IRV +TV + ERV.
Hence, the correct answer is option C.

Note: The sum total of all volumes is defined as the Total lung capacity or TLC. TLC is defined as the sum of VC (Vital capacity) and RV (Reserve volume). Vital capacity is the sum of Tidal volume (TV), Inspiratory reserve volume (IRV), and Expiratory reserve volume (ERV).