A decrease in perfusion of the alveoli will lead to which of the following?

a. Alveolar shunt c. Anatomic dead space
b. Extra-alveolar shunt d. Physiologic dead space

ANS: D
A decrease of perfusion to the alveoli causes an increase in ventilation without perfusion, which is physiologic dead space. A shunt is perfusion without ventilation. Anatomic dead space is the normal amount of dead space in the body due to the conducting airways.