3.1 Levitzky Ch 6

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Which gas has the fastest equilibration between alveolar partial pressure and partial pressure in blood?

Carbon monoxide

Nitrous oxide (correct)

Oxygen

None of the above

What factor limits the diffusion of carbon monoxide from the alveolus to the pulmonary capillary blood?

Rapid equilibration with the alveolar partial pressure

Surface area and thickness of the barrier

Diffusivity in the barrier (correct)

Chemical combination with hemoglobin

Why does the partial pressure of carbon monoxide in the pulmonary capillary blood not match that of the alveoli?

High inspired concentration of carbon monoxide

Chemical combination with hemoglobin (correct)

Rapid equilibration with the alveolar partial pressure

Low diffusivity in the alveolar-capillary barrier

Why is carbon monoxide transfer considered diffusion-limited rather than perfusion-limited?

Chemical combination with hemoglobin (D) Signup and view all the answers

At resting cardiac outputs, how long does blood typically spend in a pulmonary capillary?

0.75 second (D) Signup and view all the answers

What contributes to the decrease in velocity of bulk flow as air approaches the alveoli during inspiration?

Increased total cross-sectional area in distal airways (A) Signup and view all the answers

How does oxygen primarily move through the alveoli according to its partial pressure gradient?

By diffusion (C) Signup and view all the answers

According to Henry's law, what determines the amount of a gas absorbed by a liquid with which it does not chemically combine?

The partial pressure of the gas and its solubility in the liquid (C) Signup and view all the answers

What determines the rate of diffusion of gas through the alveolar-capillary barrier according to Fick's law for diffusion?

Surface area, diffusivity, and barrier thickness (A) Signup and view all the answers

How does an increase in capillaries recruited during exercise impact the surface area available for diffusion?

Increases surface area for diffusion (C) Signup and view all the answers

What factor can increase the transfer of nitrous oxide from a particular alveolus to its pulmonary capillary?

Increasing the time blood stays in the pulmonary capillary (C) Signup and view all the answers

At what point does oxygen transfer from alveolus to pulmonary capillary become perfusion-limited?

When the partial pressure of oxygen in the blood rises to that in the alveolus (C) Signup and view all the answers

What happens to the partial pressure gradient across the alveolar-capillary membrane when oxygen is chemically bound to hemoglobin?

It becomes negligible (D) Signup and view all the answers

What effect does exercise have on the time blood spends in the pulmonary capillary?

It decreases, allowing less time for gas exchange (A) Signup and view all the answers

How does increasing cardiac output affect nitrous oxide transfer in pulmonary capillaries?

It increases nitrous oxide transfer by decreasing equilibration time (C) Signup and view all the answers

What is the relationship between solubility and diffusion through the alveolar-capillary barrier?

Directly proportional (B) Signup and view all the answers

According to Graham's law, what is the relative rate of diffusion of two gases inversely proportional to?

The square roots of their molecular weights (B) Signup and view all the answers

Which factor is NOT a component that limits the movement of a gas through the alveolar-capillary barrier according to Fick's law for diffusion?

Molecular weight of the gas (B) Signup and view all the answers

Why is the partial pressure gradient of a gas across the barrier considered a major determinant of its rate of diffusion?

It determines how gases move from mixed venous blood to pulmonary capillaries (B) Signup and view all the answers

What is the main difference between gas movement by diffusion and gas movement through conducting airways?

Gas movement by diffusion is based on partial pressure gradients, while gas movement through conducting airways is based on differences in total pressure. (C) Signup and view all the answers

Why does gas transfer during diffusion depend on temperature?

Temperature influences molecular movement, with higher temperatures leading to increased molecular movement. (D) Signup and view all the answers

How does gas transfer occur in a static situation?

Gas transfer stops as equilibrium is reached, and no partial pressure differences exist for any gases. (C) Signup and view all the answers

Why does the net movement of gas during diffusion depend on the partial pressure difference?

The area with higher partial pressure has proportionately more random 'departures', leading to a net movement towards lower partial pressure. (C) Signup and view all the answers

How does Fick's Law describe oxygen transfer into the alveoli?

Oxygen is brought into the alveoli by bulk flow through the conducting airways. (A) Signup and view all the answers

What contributes to the increased total oxygen transfer during exercise?

Recruitment of previously unperfused capillaries (B) Signup and view all the answers

When might a person experience diffusion limitation of oxygen transfer?

During normal rest with an extremely abnormal alveolar-capillary barrier (B) Signup and view all the answers

What sets the upper limit for the end-capillary blood PO2?

Low alveolar PO2 (B) Signup and view all the answers

In a normal person, why is carbon dioxide transfer typically perfusion-limited?

Normal partial pressure gradient for carbon dioxide (C) Signup and view all the answers

What is the diffusing capacity of the lung?

The rate of gas uptake per unit pressure gradient (D) Signup and view all the answers

What does the diffusing capacity of the lung depend on?

Both diffusing capacity of the membrane and reaction with hemoglobin (A) Signup and view all the answers

Why is carbon monoxide most frequently used in determinations of the diffusing capacity?

Its mean pulmonary capillary partial pressure is virtually zero at nonlethal alveolar partial pressures (B) Signup and view all the answers

What happens to the DLCO in conditions causing interstitial or alveolar fibrosis?

It decreases (C) Signup and view all the answers

Which conditions lead to a decrease in the surface area available for diffusion?

Emphysema and tumors (C) Signup and view all the answers

What happens to the DLCO in conditions leading to ventilation-perfusion mismatch?

It decreases (B) Signup and view all the answers

What does DM represent in determining the diffusing capacity of the lung?

Diffusing capacity of the membrane (C) Signup and view all the answers

The diffusing capacity of the lung is solely determined by the diffusing capacity of the membrane, DM.

False (B) Signup and view all the answers

Carbon monoxide diffusion is considered perfusion-limited rather than diffusion-limited.

False (B) Signup and view all the answers

The DLCO decreases in conditions associated with decreased surface area available for diffusion, such as emphysema.

True (A) Signup and view all the answers

Ventilation-perfusion mismatch can lead to an increase in the surface area available for diffusion.

False (B) Signup and view all the answers

3.1 Levitzky Ch 6

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Questions and Answers

Which gas has the fastest equilibration between alveolar partial pressure and partial pressure in blood?

What factor limits the diffusion of carbon monoxide from the alveolus to the pulmonary capillary blood?

Why does the partial pressure of carbon monoxide in the pulmonary capillary blood not match that of the alveoli?

Why is carbon monoxide transfer considered diffusion-limited rather than perfusion-limited?

At resting cardiac outputs, how long does blood typically spend in a pulmonary capillary?

What contributes to the decrease in velocity of bulk flow as air approaches the alveoli during inspiration?

How does oxygen primarily move through the alveoli according to its partial pressure gradient?

According to Henry's law, what determines the amount of a gas absorbed by a liquid with which it does not chemically combine?

What determines the rate of diffusion of gas through the alveolar-capillary barrier according to Fick's law for diffusion?

How does an increase in capillaries recruited during exercise impact the surface area available for diffusion?

What factor can increase the transfer of nitrous oxide from a particular alveolus to its pulmonary capillary?

At what point does oxygen transfer from alveolus to pulmonary capillary become perfusion-limited?

What happens to the partial pressure gradient across the alveolar-capillary membrane when oxygen is chemically bound to hemoglobin?

What effect does exercise have on the time blood spends in the pulmonary capillary?

How does increasing cardiac output affect nitrous oxide transfer in pulmonary capillaries?

What is the relationship between solubility and diffusion through the alveolar-capillary barrier?

According to Graham's law, what is the relative rate of diffusion of two gases inversely proportional to?

Which factor is NOT a component that limits the movement of a gas through the alveolar-capillary barrier according to Fick's law for diffusion?

Why is the partial pressure gradient of a gas across the barrier considered a major determinant of its rate of diffusion?

What is the main difference between gas movement by diffusion and gas movement through conducting airways?

Why does gas transfer during diffusion depend on temperature?

How does gas transfer occur in a static situation?

Why does the net movement of gas during diffusion depend on the partial pressure difference?

How does Fick's Law describe oxygen transfer into the alveoli?

What contributes to the increased total oxygen transfer during exercise?

When might a person experience diffusion limitation of oxygen transfer?

What sets the upper limit for the end-capillary blood PO2?

In a normal person, why is carbon dioxide transfer typically perfusion-limited?

What is the diffusing capacity of the lung?

What does the diffusing capacity of the lung depend on?

Why is carbon monoxide most frequently used in determinations of the diffusing capacity?

What happens to the DLCO in conditions causing interstitial or alveolar fibrosis?

Which conditions lead to a decrease in the surface area available for diffusion?

What happens to the DLCO in conditions leading to ventilation-perfusion mismatch?

What does DM represent in determining the diffusing capacity of the lung?

The diffusing capacity of the lung is solely determined by the diffusing capacity of the membrane, DM.

Carbon monoxide diffusion is considered perfusion-limited rather than diffusion-limited.

The DLCO decreases in conditions associated with decreased surface area available for diffusion, such as emphysema.

Ventilation-perfusion mismatch can lead to an increase in the surface area available for diffusion.

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