Questions: 17. These pulmonary function tests are commonly used to identify different types of lung disease and to help track the progression of the problem. Understanding how these tracings change under various conditions is important. If a person had an obstructive airway and/or restrictive lung disease, it would alter the normal spirometry tracing in Exercise 1. For each of the diseases below, would the vital capacity and rate of air movement during inspiration and expiration be altered? Explain and be specific in your explanation. a. obstructive airway disease: b. restrictive lung disease:

To address the question, we need to understand how obstructive airway disease and restrictive lung disease affect spirometry tracings, specifically focusing on vital capacity and the rate of air movement during inspiration and expiration.

a. Obstructive Airway Disease:

• Vital Capacity (VC): In obstructive airway diseases, such as asthma or chronic obstructive pulmonary disease (COPD), the vital capacity may be normal or slightly reduced. This is because the total volume of air that can be exhaled after a full inhalation is not significantly affected, but the rate at which air can be expelled is impaired.
• Rate of Air Movement: The hallmark of obstructive diseases is a reduced rate of air movement, particularly during expiration. This is due to narrowed airways, which increase resistance and make it difficult to expel air quickly. This is often reflected in a decreased Forced Expiratory Volume in 1 second (FEV1) and a reduced FEV1/FVC (Forced Vital Capacity) ratio.

b. Restrictive Lung Disease:

• Vital Capacity (VC): In restrictive lung diseases, such as pulmonary fibrosis or interstitial lung disease, the vital capacity is typically reduced. This is because the lungs are unable to expand fully, leading to a decreased total volume of air that can be inhaled and exhaled.
• Rate of Air Movement: The rate of air movement may be normal or even increased relative to the reduced lung volumes. However, both inspiration and expiration volumes are reduced due to the decreased lung compliance and capacity. The FEV1/FVC ratio is often normal or increased because both FEV1 and FVC are proportionally reduced.

In summary, obstructive airway disease primarily affects the rate of air movement during expiration, while restrictive lung disease primarily reduces the vital capacity due to limited lung expansion.