Which of the following volumes or capacities cannot be measured by simple spirometry? 1. Functional residual capacity (FRC) 2. Expiratory reserve volume (ERV) 3. Residual volume (RV) 4. Inspiratory reserve volume (IRV)

a. 1, 3, and 4 only
b. 1, 2, 3, and 4
c. 1 and 3 only
d. 1 and 4 only

ANS: C
The four lung capacities are TLC, inspiratory capacity (IC), FRC, and the VC. These volumes and capacities are shown in Figure 20-10. The lung volumes that can be measured directly with a spirometer or pneumotachometer include VT, IC, IRV, ERV, and VC.