An increase in dead space results in
A)increases in both alveolar and pulmonary ventilation.
B)decreases in both alveolar and pulmonary ventilation.
C)a decrease in alveolar ventilation but no change in pulmonary ventilation.
D)an increase in alveolar ventilation but a decrease in pulmonary ventilation.
E)a decrease in alveolar ventilation but an increase in pulmonary ventilation.

Question

Quizplus · Accepted Answer

Dead space is the portion of the respiratory system where no gas exchange occurs, such as the conducting airways (trachea, bronchi, bronchioles). An increase in dead space means there is more air that is not participating in gas exchange. As a result, there is a decrease in alveolar ventilation (the amount of fresh air that reaches the alveoli and participates in gas exchange) because of the increased volume of air in the conducting airways. However, the pulmonary ventilation (the total amount of air that moves in and out of the lungs) is not affected by dead space.

An Increase in Dead Space Results in