When examining lung tissues, histologists may observe changes in the alveolar structure, interstitial spaces, and airway morphology. These histological changes can directly influence the FVC ratio. For instance, in conditions like pulmonary fibrosis, the thickening of the alveolar walls and interstitial spaces can reduce lung compliance, leading to a decrease in both FEV1 and FVC, but often with a preserved or increased ratio due to a similar proportional reduction.
