Final answer:
Restrictive lung diseases are characterized by decreased compliance of the lung tissue, leading to stiff or fibrotic airways. Patients with restrictive lung diseases have a reduced forced or functional vital capacity (FVC) and prolonged exhalation time. Spirometry can be used to detect restrictive lung diseases by measuring the rate of expelled air and the ratio between FEV1 and FVC.
Step-by-step explanation:
Restrictive lung diseases are characterized by decreased compliance of the lung tissue, leading to stiff or fibrotic airways. Examples of restrictive lung diseases include respiratory distress syndrome and pulmonary fibrosis. In these diseases, the intrapleural pressure is positive, causing the airways to collapse upon exhalation and trapping air in the lungs. Patients with restrictive lung diseases have a reduced forced or functional vital capacity (FVC) and prolonged exhalation time.
Restrictive lung diseases can be detected using spirometry, which measures the rate at which air can be expelled from the lungs. The ratio of the amount of air that can be forcibly exhaled in one second (FEV1) to the total amount of air that can be forcibly exhaled (FVC) can be used to diagnose whether a person has a restrictive or obstructive lung disease. In restrictive lung disease, FVC is reduced but airways are not obstructed, resulting in a higher FEV1/FVC ratio compared to obstructive lung disease.
Changes in compliance and resistance of the lung can also alter breathing and gas exchange. Decreased compliance, as seen in restrictive diseases, leads to stiffening and collapse of the airways, making breathing more difficult. On the other hand, increased resistance, as seen in asthma or emphysema, can obstruct the airways and trap air in the lungs, causing breathing difficulties. Alterations in ventilation and perfusion can further affect gas exchange.