Final answer:
Emphysema leads to reduced ERV and IRV due to destruction of alveoli, decreased elastic recoil, and difficulties in the elastic work conducted by the respiratory muscles.
Step-by-step explanation:
The expiratory reserve volume (ERV) and the inspiratory reserve volume (IRV) are typically lower in individuals with emphysema than in healthy individuals due to the pathophysiological changes in the lungs caused by the disease.
Emphysema is characterized by the destruction of alveoli, leading to a decrease in elastic recoil, which is the property of the lung that drives lung tissue inward after, resulting in air becoming trapped.
Moreover, the work conducted by the intercostal muscles, chest wall, and diaphragm, known as elastic work, is adversely affected in emphysema.The reduced lung elasticity makes it more difficult for these muscles to help exhale the air fully, thereby reducing the ERV.
Similarly, due to the altered lung structure and decreased elasticity, less air can be inhaled deeply after a normal inhalation, which in turn reduces the IRV.
Experimental data, such as the FEV1/FVC ratio, which measures the amount of air expelled from the lungs in one second relative to the total amount expelled, often reveals lower values in emphysema patients.
This ratio is indicative of obstructive lung diseases and is used to support the diagnosis of emphysema. In emphysema, the FEV1 is notably reduced because of the increased airway resistance and reduced recoil, confirming the functional impairment.