WorksheetsCh. 7 Beachey
Total questions: 24
Worksheet time: 48mins
What is the most common cause of resting hypoxemia?
A mismatch between ventilation and diffusion
A mismatch between ventilation and permeability
A mismatch between ventilation and dead space
A mismatch between ventilation and blood flow
Why is N2O the ideal gas for measuring the extent to which pulmonary blood contributes to the diffusion rate?
Blood can absorb N2O at a greater rate than N2O can diffuse across the alveolar-capillary membrane.
If N2O is inhaled, the pulmonary capillary blood reaches its maximum capacity for N2O almost instantly.
If N2O is inhaled, the pulmonary capillary blood reaches its maximum capacity for N2O slowly.
Blood can absorb N2O at a slower rate than N2O can diffuse across the alveolar-capillary membrane.
Which of the following is the main limiting factor for oxygen transfer rate?
Perfusion
Diffusion
Solubility
Molecular weight of the gas
If oxygen equilibrium between the alveolus and capillary never occurs because of thickened membranes, oxygen transfer is then truly:
perfusion limited.
diffusion limited.
concentration limited.
perfusion and diffusion limited.
Why is CO the ideal gas for measuring the extent to which the alveolar-capillary membrane itself impedes the diffusion rate?
Blood can absorb CO at a greater rate than CO can diffuse across the alveolar-capillary membrane.
CO is lighter than O2.
CO can diffuse across the alveolar-capillary membrane faster than blood can absorb it.
CO is heavier than O2.
When breathing 21% oxygen, what is the inspired oxygen partial pressure?
Approximately 80 mm Hg
Approximately 100 mm Hg
Approximately 140 mm Hg
Approximately 160 mm Hg
Which of the following conditions can increase the length of the diffusion path?
Fibrotic thickening of alveolar and capillary walls
Surfactant in the alveoli
Capillary vasocontriction
Presence of alveolar macrophages
How do you obtain the diffusion capacity for oxygen?
It is obtained by multiplying DLCO by 1.23.
It is obtained by multiplying DLCO by 24.
It is obtained by dividing DLCO by 1.23.
It is obtained by dividing DLCO by 24.
The DLCO is useful in differentiating emphysema from what other obstructive diseases?
Asthma
Pneumonia
ARDS
Bronchiectasis
What is the PAO2 of a person breathing room air at sea level, with a PaCO2 equal to 40 mm Hg and an R equal to 0.8?
Approximately 80 mm Hg
Approximately 90 mm Hg
Approximately 100 mm Hg
Approximately 110 mm Hg
Which of the following options displays in order the components of the diffusion path that oxygen has to go through?
Capillary endothelium, intracellular fluid bathing the hemoglobin molecule, red blood cell membrane, alveolar epithelium, surfactant layer lining the alveolar surface
Surfactant layer lining the alveolar surface, alveolar epithelium, capillary endothelium, red blood cell membrane, intracellular fluid bathing the hemoglobin molecule
Alveolar epithelium, surfactant layer lining the alveolar surface, capillary endothelium, intracellular fluid bathing the hemoglobin molecule, red blood cell membrane
Surfactant layer lining the alveolar surface, alveolar epithelium, red blood cell membrane, capillary endothelium, intracellular fluid bathing the hemoglobin molecule
Which of the following statements is consistent with the respiratory exchange ratio?
It is the ratio of alveolar N2O excretion to blood oxygen uptake.
R =V CO2/V O2
It is the ratio of oxygen uptake to blood alveolar CO2 excretion.
Its value is normally approximately 1.0.
Which of the following laws states that the amount of gas dissolving in a liquid is directly proportional to the gas partial pressure?
Boyle’s law
Charles’ law
Henry’s law
Reynolds’ law
How many times faster does oxygen diffuse through a gas medium than CO2?
0.9
1.0
1.1
1.2
What is the best explanation for the DLO2 to be greater than the DLCO?
O2 is less soluble than CO in the alveolar-capillary membrane but higher in the plasma and therefore diffuses more rapidly.
O2 is more soluble than CO in the alveolar-capillary membrane and lower in the plasma and therefore diffuses more rapidly.
O2 is less soluble than CO in the alveolar-capillary membrane and the plasma and therefore diffuses more rapidly.
O2 is more soluble than CO in the alveolar-capillary membrane and the plasma and therefore diffuses more rapidly.
When combining Graham’s law and Henry’s law, how many times faster does carbon dioxide diffuse across the alveolar-capillary membrane than oxygen?
10
20
30
40
What is the mean DLCO range for healthy adults?
20 to 22 mL/min/mm Hg
30 to 40 mL/min/mm Hg
40 to 50 mL/min/mm Hg
50 to 60 mL/min/mm Hg
When are patients with thickened alveolar-capillary membranes most likely to show evidence of oxygen diffusion impairment?
In supine position
In prone position
During exercise
In any position at rest
The rate of gas diffusion in the lung is inversely proportional to its molecular weight and directly proportional to which of the following physical properties?
Density
Solubility
Specific gravity
Proton concentration
Diffusion of which of the following gases will be limited by a defective alveolar-capillary membrane?
O2
CO2
NO
N2O
Which of the following conditions has an inverse relationship with DLCO?
Age
Exercise
Lung volumes
PAO2
CO2 is how many times more soluble than O2?
16
20
24
28
Which of the following statements apply to Fick’s law?
Gas diffusion increases with increased membrane surface area.
Gas diffusion increases with decreased membrane surface area.
Gas diffusion decreases with increased pressure gradient.
Gas diffusion decreases if membrane thickness decreases.
How does the RCP describe alveolar pressure (Palv) during normal quiet breathing? “Alveolar pressure during normal quiet breathing is
Negative during inspiration and positive during expiration."
Always less than atmospheric pressure."
Same as the airway opening pressure during inspiration."
The same as intrapleural pressure (Ppl)."
