Functional residual capacity decreases in which disease pattern?

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Multiple Choice

Functional residual capacity decreases in which disease pattern?

FRC is the amount of air left in the lungs after a normal exhale, determined by the balance of lung recoil and chest wall tendency to expand. In restrictive disease, the lungs become stiffer and lung volumes are reduced overall (decreased compliance and TLC). Because the lungs can’t inflate as much and the resting end-expiratory position shifts to a lower volume, functional residual capacity falls. In contrast, obstructive patterns (with air trapping and loss of elastic recoil) tend to increase FRC, normal aging can raise FRC, and an acute asthma attack behaves like an obstructive process with increased air trapping. So the pattern that decreases FRC is restrictive disease.

FRC is the amount of air left in the lungs after a normal exhale, determined by the balance of lung recoil and chest wall tendency to expand. In restrictive disease, the lungs become stiffer and lung volumes are reduced overall (decreased compliance and TLC). Because the lungs can’t inflate as much and the resting end-expiratory position shifts to a lower volume, functional residual capacity falls.

In contrast, obstructive patterns (with air trapping and loss of elastic recoil) tend to increase FRC, normal aging can raise FRC, and an acute asthma attack behaves like an obstructive process with increased air trapping. So the pattern that decreases FRC is restrictive disease.

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