What can excessive pathology in the lungs lead to in terms of gas exchange?

• A. Increased oxygen utilization
• B. Improved CO2 elimination
• C. Diffusion limitations
• D. Enhanced lung elasticity

Answer: (C)

Excessive pathology in the lungs can result in diffusion limitations, which refers to the impaired ability of oxygen and carbon dioxide to move across the alveolar-capillary membrane. When lung tissue is damaged or diseased, factors such as inflammation, fluid accumulation, or destruction of alveoli can create a barrier that hinders normal gas exchange.

In a healthy lung, oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled. However, when pathology increases within the lungs—such as in conditions like pulmonary fibrosis or severe pneumonia—the effectiveness of this diffusion process is reduced. This leads to decreased oxygen levels in the blood (hypoxemia) and can also affect CO2 elimination, although primarily it is diffusion of oxygen that is critically affected under these circumstances.

The other options do not accurately describe the impact of excessive lung pathology on gas exchange. Increased oxygen utilization suggests a more efficient use of oxygen, which does not occur in pathological conditions. Improved CO2 elimination implies that the lungs are functioning optimally, which is contrary to the effects of lung disease. Enhanced lung elasticity would indicate better lung function, which is typically compromised during disease progression.