An area of the lung has no blood flow but is normally ventilated. Which of the following statements are true about this area?
1) The alveolar gas is like air (PO₂ = 150; PCO₂ = 0) .
2) The area represents alveolar dead space.
3) The / is elevated.

Question

Quizplus · Accepted Answer

In an area of the lung with no blood flow but normal ventilation, the alveolar gas composition becomes similar to atmospheric air because there is no blood to take away the oxygen or bring in carbon dioxide, which makes statement 1 true. This situation is an example of alveolar dead space, as ventilation occurs without perfusion, making statement 2 true. The ventilation/perfusion ratio (V/Q) is elevated because perfusion (Q) is zero, making the ratio infinitely high, which validates statement 3.

An Area of the Lung Has No Blood Flow but Is