37 Questions
Which type of gas transfer is N2O an example of?
Perfusion-limited
What is the equilibration time for N2O, as mentioned in the text?
~0.15 s
Which gas is normally perfusion-limited?
O2
What property makes CO a diffusion-limited gas?
Binds readily to Hb
How does the transfer of CO differ from that of O2?
CO is only limited by properties of the respiratory membrane.
In the context of Fick's Law of Diffusion, the rate of diffusion of a gas through a tissue sheet is directly proportional to which of the following?
Solubility coefficient of the gas
Which factor significantly influences the diffusion coefficient of a gas in a liquid according to Fick's Law?
Temperature
When considering Graham's Law of Diffusion, what does the faster diffusion of carbon dioxide compared to oxygen primarily depend on?
Molecular weight
How does an increase in membrane thickness impact the rate of diffusion of gases through the membrane, according to Fick's Law?
It decreases the rate of diffusion
What is the relationship between the square root of the diffusion coefficient and the rate of gas diffusion through a tissue sheet in Fick's Law?
No relationship
According to Fick's Law of Diffusion, which of the following factors impacts the rate of diffusion?
Thickness of the membrane
How does an increased solubility of a gas affect its rate of diffusion?
Increases it
In terms of Graham’s Law, what does a lower molecular weight of a gas indicate?
It diffuses faster
How does an increase in the surface area available for diffusion affect the rate of diffusion?
Speeds it up
What is the impact of an increased thickness of the alveolar-capillary unit on the rate of diffusion?
It slows down the diffusion rate
What is the primary factor that determines the diffusing capacity of the lung?
Thickness of the respiratory membrane
Which gas is often used to measure the diffusing capacity of the lung due to its nonlethal nature?
Carbon monoxide (CO)
What limits oxygen consumption in the body during physical activities?
Maximal cardiac output
How can the diffusing capacity of oxygen be increased during exercise?
By increasing ventilation and pressure gradient
What happens to mixed venous PO2 levels during exercise compared to rest?
It decreases
Which factor is directly proportional to the rate at which a gas diffuses according to Fick's Law of Diffusion?
Solubility coefficient
Based on Graham's Law, what can be concluded about the diffusion rates of CO2 and O2?
O2 diffuses faster due to its heavier molecular weight
In the context of diffusion, what effect does an increase in barrier thickness have on the process?
Slows down diffusion
What is the relationship between the solubility of a gas and its rate of diffusion in a liquid?
The more soluble gas diffuses faster
How does the diffusion coefficient for CO2 compare to that of O2 based on their molecular weights and solubility coefficients?
CO2 has a higher diffusion coefficient due to its higher solubility coefficient
In what situation can oxygen become diffusion limited?
When there is a thickening of the alveolar-capillary membrane
Why are conditions of respiratory membrane impairment reflected as hypoxia instead of hypercapnia?
Because CO2 is more soluble than O2 in the alveolar–capillary membrane
What test assesses lung function by having the patient walk a specific distance and measuring SpO2?
Six-Minute Walk Test
What factor does NOT limit O2 diffusion according to the text?
Decreased time available for exchange due to increased flow velocity
Why is CO2 normally not diffusion limited in its exchange compared to O2?
Because CO2 has a higher diffusion coefficient than O2
What type of transfer is limited by the rate of pulmonary blood flow?
Perfusion-limited transfer
Which gas transfer type occurs when a gas does not equilibrate between alveoli and pulmonary capillary blood plasma?
Diffusion-limited transfer
What factor limits the amount of gas transfer in perfusion-limited transfer?
Rate of pulmonary blood flow
For diffusion-limited transfer, what limits the amount of gas transferred across the alveolar-capillary unit?
Pressure gradient maintained by the gas
Which type of gas transfer is limited by the ability of a gas to diffuse?
Diffusion-limited transfer
In perfusion-limited transfer, what determines the amount of gas transfer across the alveolar-capillary unit?
Rate of pulmonary blood flow
Which factor plays a key role in determining if a gas transfer is perfusion-limited or diffusion-limited?
Diffusion coefficient
Test your knowledge on diffusing capacity and transfer factor in the lungs. Learn about the rate at which oxygen and carbon dioxide diffuse through the respiratory membrane. Explore factors influencing the diffusing capacity of the lung.
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