Final answer:
Restrictive airway diseases decrease lung compliance due to stiffening or fibrosis of airways, leading to difficulty in breathing and reducing the amount of air that can be forcibly exhaled after a deep breath.
Step-by-step explanation:
Restrictive airway diseases decrease lung compliance. This is because conditions like respiratory distress syndrome and pulmonary fibrosis lead to the airways becoming less compliant—they become stiff or fibrotic. A consequence of decreased compliance is that the lung tissue has a reduced ability to bend and move. During exhalation in such diseases, the intrapleural pressure becomes more positive, causing the airways to collapse and ultimately trapping air within the lungs. Therefore, patients with these diseases exhibit lower Forced or Functional Vital Capacity (FVC) than in healthy individuals, and they have trouble exhaling the normal amount of air due to the prolonged exhalation time. Contrary to lung compliance, resistance in the respiratory system can increase when obstructed by conditions such as asthma, leading to difficulty in breathing and compromised gas exchange.