Low levels of surfactant would lead to which consequence in the alveoli?

Low levels of surfactant would lead to which consequence in the alveoli?

• A. Increased diffusion of gases
• B. Alveolar collapse due to high surface tension
• C. Decreased airway resistance
• D. Diffuse alveolar swelling

Answer: (B)

Surfactant lowers surface tension in the alveoli, keeping them open as you breathe out and improving lung compliance. When surfactant levels are low, surface tension remains high, and small alveoli have a much greater tendency to collapse because the pressure needed to keep them open is inversely related to their radius (the smaller the alveolus, the higher the pressure required). This causes atelectasis, reducing the surface area for gas exchange and making breathing harder. That’s why the likely consequence is alveolar collapse due to high surface tension. The other options don’t fit as the direct outcome: high surface tension from lack of surfactant doesn’t increase diffusion of gases; it tends to hamper gas exchange by reducing open surface area. It doesn’t specifically decrease airway resistance; in fact, surfactant deficiency can increase the work of breathing and resistance via unstable airways. Diffuse alveolar swelling isn’t a direct result of low surfactant, which is more about collapse than fluid accumulation.

Surfactant lowers surface tension in the alveoli, keeping them open as you breathe out and improving lung compliance. When surfactant levels are low, surface tension remains high, and small alveoli have a much greater tendency to collapse because the pressure needed to keep them open is inversely related to their radius (the smaller the alveolus, the higher the pressure required). This causes atelectasis, reducing the surface area for gas exchange and making breathing harder. That’s why the likely consequence is alveolar collapse due to high surface tension.

The other options don’t fit as the direct outcome: high surface tension from lack of surfactant doesn’t increase diffusion of gases; it tends to hamper gas exchange by reducing open surface area. It doesn’t specifically decrease airway resistance; in fact, surfactant deficiency can increase the work of breathing and resistance via unstable airways. Diffuse alveolar swelling isn’t a direct result of low surfactant, which is more about collapse than fluid accumulation.