How can particulates impede oxygen transfer in the lungs?

How can particulates impede oxygen transfer in the lungs?

• A. By creating a barrier in the alveoli that blocks transfer to the bloodstream
• B. By increasing blood oxygen saturation
• C. By dissolving alveolar tissue to improve diffusion
• D. By thinning the alveolar septa

Answer: (A)

Gas exchange relies on oxygen diffusing from the air in the alveoli across the thin alveolar-capillary membrane into the blood. Particulates irritate and inflame this region, causing edema and remodeling of the alveolar walls. This thickens the diffusion barrier and can reduce the effective surface area, so the rate at which O2 moves into the bloodstream drops. In short, the presence of particulates creates a barrier that blocks or greatly slows transfer of oxygen to the blood. Increasing oxygen saturation wouldn’t occur from particulates, and dissolving tissue or thinning the alveolar septa would actually enhance diffusion, not impede it.

Gas exchange relies on oxygen diffusing from the air in the alveoli across the thin alveolar-capillary membrane into the blood. Particulates irritate and inflame this region, causing edema and remodeling of the alveolar walls. This thickens the diffusion barrier and can reduce the effective surface area, so the rate at which O2 moves into the bloodstream drops. In short, the presence of particulates creates a barrier that blocks or greatly slows transfer of oxygen to the blood. Increasing oxygen saturation wouldn’t occur from particulates, and dissolving tissue or thinning the alveolar septa would actually enhance diffusion, not impede it.