For a gas with a low blood-gas partition coefficient, what does this imply about absorption and which factor mainly controls transfer?

For a gas with a low blood-gas partition coefficient, what does this imply about absorption and which factor mainly controls transfer?

• A. Gas dissolves well in blood
• B. Gas dissolves moderately in blood
• C. Gas does not dissolve well in blood, so majority stays in alveoli
• D. Transfer is dominated by diffusion

Answer: (C)

A gas with a low blood-gas partition coefficient is poorly soluble in blood. Because of that, only a small portion of the inhaled gas dissolves into the blood at the alveolar–capillary interface, so the majority remains in the alveolar space. This directly describes the absorption behavior: limited uptake into blood due to poor solubility. In other words, the transfer is constrained by the gas’s inability to dissolve and diffuse into blood, rather than being carried away by high blood solubility. The other options imply greater solubility or misstate what governs the transfer, so the description that most of the gas stays in the alveoli best fits a gas with a low partition coefficient.

A gas with a low blood-gas partition coefficient is poorly soluble in blood. Because of that, only a small portion of the inhaled gas dissolves into the blood at the alveolar–capillary interface, so the majority remains in the alveolar space. This directly describes the absorption behavior: limited uptake into blood due to poor solubility. In other words, the transfer is constrained by the gas’s inability to dissolve and diffuse into blood, rather than being carried away by high blood solubility. The other options imply greater solubility or misstate what governs the transfer, so the description that most of the gas stays in the alveoli best fits a gas with a low partition coefficient.