Final answer:
Exhalation/inhalation can be impaired in restrictive lung diseases while oxygen perfusion remains normal, as the airways become stiff or fibrotic, leading to trapped air in the lungs.
Step-by-step explanation:
Oxygen perfusion may be normal, while exhalation/inhalation is impaired in cases of restrictive lung diseases. Restrictive diseases such as respiratory distress syndrome and pulmonary fibrosis lead to decreased compliance of the lung tissues. This results in stiff or fibrotic airways that cannot bend and move properly. The airways may collapse upon exhalation, leading to air becoming trapped in the lungs and making it difficult to breathe normally. This condition results in a lower Forced Vital Capacity (FVC) and prolonged exhalation times in affected patients. Their ability to exhale the normal amount of air is compromised, contrasting with conditions like asthma where the obstruction of airways leads to difficulty in breathing due to increased inflammation and narrowing of the airways.