Question

In the following functional human lung studies, identify the total lung capacity.
A) Inspiratory capacity (IC)
B) Functional residual capacity (FRC)
C) Vital capacity (VC)
D) Inspiratory reserve volume (IRV)
E) Residual volume (RV)
F) Expiratory reserve volume (ERV)
G) Tidal volume (TV)
The correct answer is

• A. (D) + (F)
• B. (A) + (D)
• C. (B) + (C)
• D. (C) + (E)

Answer 1

The correct option is D (C) + (E)

The inspiratory capacity (IC), about 3,600 mL, is the maximum amount of air that can be inspired (IC = TV + IRV).
The functional residual capacity (FRC), about 2,400 mL, is the amount of air remaining in the lungs after a normal expiration (FRC = RV + ERV).
Vital capacity is the maximum amount of air a person can expel from the lungs after a maximum inhalation. It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume.
The expiratory reserve volume (ERV), about 1,200 mL, is the additional air that can be forcibly exhaled after the expiration of a normal tidal volume.
Residual volume (RV), about 1,200 mL, is the volume of air still remaining in the lungs after the expiratory reserve volume is exhaled. The tidal volume (TV), about 500 mL, is the amount of air inspired during normal, relaxed breathing.
The lung capacities that can be calculated include vital capacity (ERV+TV+IRV), inspiratory capacity (TV+IRV), functional residual capacity (ERV+RV), and total lung capacity (RV+ERV+TV+IRV).

Thus the correct answer is option D.