What two properties does diffusion capacity of the lung (DL) depend on?

What two properties does diffusion capacity of the lung (DL) depend on?

• A. Gas and temperature
• B. Gas and volume
• C. Gas and membrane properties
• D. Gas and pressure

Answer: (C)

The diffusion capacity of the lung (DL) is fundamentally influenced by the type of gas and the properties of the alveolar-capillary membrane through which the gas diffuses. The type of gas is crucial because different gases have different molecular weights and solubility in liquid, which affects how rapidly they can diffuse across the membrane. For example, carbon dioxide diffuses more quickly than oxygen due to its higher solubility in blood. The properties of the membrane include factors such as its surface area, thickness, and the presence of any pathologies that may alter its integrity. A healthy, well-structured membrane allows for efficient gas exchange, while conditions such as pulmonary edema or fibrosis can impair diffusion, reducing the overall capacity for gas exchange. The other options, while they contain terms related to gas and basic physical principles, do not accurately represent the specific factors that determine DL in the context of the lungs and gas exchange. For instance, temperature and pressure are more associated with general gas laws rather than the specific physiology of lung diffusion capacity.

The diffusion capacity of the lung (DL) is fundamentally influenced by the type of gas and the properties of the alveolar-capillary membrane through which the gas diffuses.

The type of gas is crucial because different gases have different molecular weights and solubility in liquid, which affects how rapidly they can diffuse across the membrane. For example, carbon dioxide diffuses more quickly than oxygen due to its higher solubility in blood.

The properties of the membrane include factors such as its surface area, thickness, and the presence of any pathologies that may alter its integrity. A healthy, well-structured membrane allows for efficient gas exchange, while conditions such as pulmonary edema or fibrosis can impair diffusion, reducing the overall capacity for gas exchange.

The other options, while they contain terms related to gas and basic physical principles, do not accurately represent the specific factors that determine DL in the context of the lungs and gas exchange. For instance, temperature and pressure are more associated with general gas laws rather than the specific physiology of lung diffusion capacity.