Which statement describes the effect of smoking on the alveoli and gaseous exchange?

Which statement describes the effect of smoking on the alveoli and gaseous exchange?

• A. Smoking damages alveoli so they are less stretchy and less efficient.
• B. Smoking increases alveolar elasticity and efficiency.
• C. Smoking improves gas exchange efficiency for smokers.
• D. Smoking has no effect on alveoli.

Answer: (A)

Smoking damages the tiny air sacs where gas exchange happens. The irritants and enzymes in smoke break down the walls of the alveoli and reduce the elastic fibres that let them stretch and recoil. This makes the alveoli less stretchy and also reduces the surface area available for diffusion. With less surface area and poorer recoil, the diffusion of gases between the alveoli and blood becomes less efficient, so oxygen uptake and carbon dioxide removal are impaired. That’s why describing the alveoli as damaged and less elastic and less efficient best matches the effect of smoking on gaseous exchange. Smoking does not improve elasticity or efficiency, and it clearly has a damaging effect on the alveoli.

Smoking damages the tiny air sacs where gas exchange happens. The irritants and enzymes in smoke break down the walls of the alveoli and reduce the elastic fibres that let them stretch and recoil. This makes the alveoli less stretchy and also reduces the surface area available for diffusion. With less surface area and poorer recoil, the diffusion of gases between the alveoli and blood becomes less efficient, so oxygen uptake and carbon dioxide removal are impaired. That’s why describing the alveoli as damaged and less elastic and less efficient best matches the effect of smoking on gaseous exchange. Smoking does not improve elasticity or efficiency, and it clearly has a damaging effect on the alveoli.