Module 4: Physiology of the Respiratory System - Curves Showing Mixed Obstructive And Restrictive Abnormalities.

Curves Showing Mixed Obstructive And Restrictive Abnormalities:

     

Obstruction with a reduced FVC: emphysema.

  • Destruction of alveolar walls leads to a loss of lung elasticity.
  • During exhalation this loss of elasticity and dynamic airways compression leads to early closure of smaller conducting airways.
  • This result in air trapping in the lung, causing hyperinflation and an increased RV.
  • TLC may increase but the net effect is still a reduced FVC.

    Obstruction with a reduced FVC: tuberculosis.

    • Tuberculosis destroys lung parenchyma, reducing lung volumes.
    • Airways are damaged or distorted resulting in airflow obstruction.
    • The balance of obstructive and non-obstructive abnormality varies.
           

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