Question 1

Which of the following best represents the partial pressures of all gases in the normally ventilated and perfused alveolus when breathing room air at sea level?

Accepted Answer

A)  PO2 = 40 mm Hg; PCO2 = 100 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg 
B)  PO2 = 100 mm Hg; PCO2 = 40 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg 
C)  PO2 = 100 mm Hg; PCO2 = 40 mm Hg; PN2 = 713 mm Hg; PH2O = 47 mm Hg 
D)  PO2 = 149 mm Hg; PCO2 = 40 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg

Question 2

In a person breathing room air (and with all else being normal), if the alveolar PCO2 rises from 40 to 70 mm Hg, what would you expect?

Accepted Answer

A)  PAO2 to fall by approximately 30 mm Hg 
B)  PAO2 to fall by approximately 40 mm Hg 
C)  PAO2 to rise by approximately30 mm Hg 
D)  PAO2 to rise by approximately 40 mm Hg

Question 3

Which of the following would you expect to find with "O2 debt"?
1) Accentuated in diseases such as sepsis.
2) O2 demand exceeds O2 delivery.
3) O2 excess usage results in debt.

Accepted Answer

A) 1, 2, and 3 
B) 1 and 2 only 
C) 2 only 
D) 2 and 3 only

Question 4

As the amount of O2 that dissolves in the plasma increases, what is it directly proportional to?

Accepted Answer

A)  Its partial pressure 
B)  Its solubility coefficient 
C)  Minute ventilation 
D)  Temperature

Question 5

If blood from an area of the lung with a high / is mixed with blood perfusing an area with a low  , what will be the result?

Accepted Answer

A)  CaO2 higher than the average of the two 
B)  CaO2 lower than the average of the two 
C)  PaO2 equal to the average of the two 
D)  PaO2 lower than the average of the two

Question 6

Which of the following values corresponds most closely to the normal PO2 and PCO2 in the mixed venous blood returning to the lungs from the right side of the heart?

Accepted Answer

A)  PO2 = 40 mm Hg; PCO2 = 46 mm Hg 
B)  PO2 = 40 mm Hg; PCO2 = 100 mm Hg 
C)  PO2 = 100 mm Hg; PCO2 = 40 mm Hg 
D)  PO2 = 100 mm Hg; PCO2 = 46 mm Hg

Question 7

The lowest PO2 would normally be found in what location?

Accepted Answer

A)  Arterial blood 
B)  Atmospheric air 
C)  Cells 
D)  Venous blood

Question 8

If the total hemoglobin content (Hb + HbO2) of a sample of blood is 20 g/dl and the oxyhemoglobin (HbO2) content is 15 g/dl, what is the HbO2 saturation?

Accepted Answer

A)  17% 
B)  50% 
C)  75% 
D)  83%

Question 9

Which of the following increases the affinity of Hb for O2?
1) Decreased 2,3-DPG
2) Decreased PCO2
3) Increased pH
4) Increased temperature

Accepted Answer

A) 1, 2, and 3 only 
B) 1, 2, and 4 only 
C) 2 and 4 only 
D) 3 and 4 only

Question 10

The oxidation of the Hb molecule's iron ions to the ferric state (Fe3+) results in which of the following?
1) Form of anemia called sickle cell anemia
2) Formation of methemoglobin (metHb)
3) Inability of metHb to bind with O2

Accepted Answer

A) 1 and 2 only 
B) 1 and 3 only 
C) 2 and 3 only 
D) 1, 2, and 3

Question 11

The PAO2 depends on which of the following factors?
1) Ambient (atmospheric) pressure
2) Fractional concentration of inspired O2
3) Level of VA
4) Types of fuels burned (fat, protein, and carbohydrate)

Accepted Answer

A) 1, 2, and 3 only 
B) 1 and 2 only 
C) 3 only 
D) 1, 2, 3, and 4

Question 12

What is the minimum amount of time that blood must take for pulmonary capillary transit for equilibration of O2 to occur across the alveolar-capillary membrane?

Accepted Answer

A)  0.15 sec 
B)  0.25 sec 
C)  0.35 sec 
D)  0.45 sec

Question 13

Which of the following "layers" must be traversed by gases moving across the alveolar-capillary membrane?
1) Alveolar epithelial membrane
2) Capillary endothelial membrane
3) Interstitial space
4) Transbronchial radial tethering mechanisms

Accepted Answer

A) 1, 2, and 3 only 
B) 1, 2, and 4 only 
C) 2 and 3 only 
D) 1, 2, 3, and 4

Question 14

In the presence of an acutely reduced arterial O2 content (hypoxemia), normal O2 delivery to the tissues can be maintained by which of the following?

Accepted Answer

A)  Hyperventilation (increased V
A)  
B)  Increased RBC production 
C)  Increasing the cardiac output 
D)  Peripheral vasoconstriction

Question 15

When using therapeutic agents that can cause methemoglobinemia (methHb), which of the following is important to prevent adverse effects?

Accepted Answer

A)  Checking the frequency of ventilation 
B)  Frequent monitoring for methHb to weigh the risk against the benefit 
C)  Occasional monitoring for sickle cell anemia 
D)  Frequent monitoring for abnormal body temperature (high or low)

Question 16

On what does the movement of gases between the lungs and the body tissues mainly depend?

Accepted Answer

A)  Active transport 
B)  Gaseous diffusion 
C)  Membrane dialysis 
D)  Membrane transport

Question 17

A patient breathing room air at sea level has the following arterial blood gases: PaO2 = 62 mm Hg; PCO2 = 75 mm Hg. When the FIO2 is raised to 0.28, the PaO2 rises to 95 mm Hg. What is the most likely cause of the hypoxemia?

Accepted Answer

A)  Hypoventilation 
B)  Impaired diffusion 
C)  Right-to-left shunt 
D)  V/Q imbalance

Question 18

The two major causes of dead space ventilation are:
1) a decreased tidal volume.
2) dysoxia.
3) impaired CO2 removal.
4) increased physiologic dead space.

Accepted Answer

A) 1 and 2 only 
B) 1 and 3 only 
C) 1 and 4 only 
D) 1, 2, and 3 only

Question 19

Assuming a constant FiO2 and carbon dioxide production, which of the following statements is correct?

Accepted Answer

A)  An increased PACO2 will result in and increased PAO2. 
B)  Increased FIO2 blows off carbon dioxide. 
C)  Increases in alveolar ventilation (V
A)  decrease the PACO2 and increase the PAO2. 
D)  The PAO2 varies proportionally with the PACO2.

Question 20

What happens when the temperature of the blood rises?
1) The Hb saturation for a given PO2 falls.
2) The HbO2 curve shifts to the right.
3) The affinity of Hb for O2 increases.

Accepted Answer

A) 1 and 2 only 
B) 1 and 3 only 
C) 2 only 
D) 1, 2, and 3

Exam 12: Gas Exchange and Transport

Which of the following best represents the partial pressures of all gases in the normally ventilated and perfused alveolus when breathing room air at sea level?

In a person breathing room air (and with all else being normal) , if the alveolar PCO₂ rises from 40 to 70 mm Hg, what would you expect?

Which of the following would you expect to find with "O₂ debt"? 1) Accentuated in diseases such as sepsis. 2) O₂ demand exceeds O₂ delivery. 3) O₂ excess usage results in debt.

As the amount of O₂ that dissolves in the plasma increases, what is it directly proportional to?

If blood from an area of the lung with a high / is mixed with blood perfusing an area with a low , what will be the result?

Which of the following values corresponds most closely to the normal PO₂ and PCO₂ in the mixed venous blood returning to the lungs from the right side of the heart?

The lowest PO₂ would normally be found in what location?

If the total hemoglobin content (Hb + HbO₂) of a sample of blood is 20 g/dl and the oxyhemoglobin (HbO₂) content is 15 g/dl, what is the HbO₂ saturation?

Which of the following increases the affinity of Hb for O₂? 1) Decreased 2,3-DPG 2) Decreased PCO₂ 3) Increased pH 4) Increased temperature

The oxidation of the Hb molecule's iron ions to the ferric state (Fe³⁺) results in which of the following? 1) Form of anemia called sickle cell anemia 2) Formation of methemoglobin (metHb) 3) Inability of metHb to bind with O₂

The PAO₂ depends on which of the following factors? 1) Ambient (atmospheric) pressure 2) Fractional concentration of inspired O₂ 3) Level of V_A 4) Types of fuels burned (fat, protein, and carbohydrate)

What is the minimum amount of time that blood must take for pulmonary capillary transit for equilibration of O₂ to occur across the alveolar-capillary membrane?

Which of the following "layers" must be traversed by gases moving across the alveolar-capillary membrane? 1) Alveolar epithelial membrane 2) Capillary endothelial membrane 3) Interstitial space 4) Transbronchial radial tethering mechanisms

In the presence of an acutely reduced arterial O₂ content (hypoxemia) , normal O₂ delivery to the tissues can be maintained by which of the following?

When using therapeutic agents that can cause methemoglobinemia (methHb) , which of the following is important to prevent adverse effects?

On what does the movement of gases between the lungs and the body tissues mainly depend?

A patient breathing room air at sea level has the following arterial blood gases: PaO₂ = 62 mm Hg; PCO₂ = 75 mm Hg. When the FIO₂ is raised to 0.28, the PaO₂ rises to 95 mm Hg. What is the most likely cause of the hypoxemia?

The two major causes of dead space ventilation are: 1) a decreased tidal volume. 2) dysoxia. 3) impaired CO₂ removal. 4) increased physiologic dead space.

Assuming a constant FiO₂ and carbon dioxide production, which of the following statements is correct?

What happens when the temperature of the blood rises? 1) The Hb saturation for a given PO₂ falls. 2) The HbO₂ curve shifts to the right. 3) The affinity of Hb for O₂ increases.

Exam 12: Gas Exchange and Transport

Which of the following best represents the partial pressures of all gases in the normally ventilated and perfused alveolus when breathing room air at sea level?

In a person breathing room air (and with all else being normal) , if the alveolar PCO2 rises from 40 to 70 mm Hg, what would you expect?

Which of the following would you expect to find with "O2 debt"? 1) Accentuated in diseases such as sepsis. 2) O2 demand exceeds O2 delivery. 3) O2 excess usage results in debt.

As the amount of O2 that dissolves in the plasma increases, what is it directly proportional to?

If blood from an area of the lung with a high / is mixed with blood perfusing an area with a low , what will be the result?

Which of the following values corresponds most closely to the normal PO2 and PCO2 in the mixed venous blood returning to the lungs from the right side of the heart?

The lowest PO2 would normally be found in what location?

If the total hemoglobin content (Hb + HbO2) of a sample of blood is 20 g/dl and the oxyhemoglobin (HbO2) content is 15 g/dl, what is the HbO2 saturation?

Which of the following increases the affinity of Hb for O2? 1) Decreased 2,3-DPG 2) Decreased PCO2 3) Increased pH 4) Increased temperature

The oxidation of the Hb molecule's iron ions to the ferric state (Fe3+) results in which of the following? 1) Form of anemia called sickle cell anemia 2) Formation of methemoglobin (metHb) 3) Inability of metHb to bind with O2

The PAO2 depends on which of the following factors? 1) Ambient (atmospheric) pressure 2) Fractional concentration of inspired O2 3) Level of VA 4) Types of fuels burned (fat, protein, and carbohydrate)

What is the minimum amount of time that blood must take for pulmonary capillary transit for equilibration of O2 to occur across the alveolar-capillary membrane?

Which of the following "layers" must be traversed by gases moving across the alveolar-capillary membrane? 1) Alveolar epithelial membrane 2) Capillary endothelial membrane 3) Interstitial space 4) Transbronchial radial tethering mechanisms

In the presence of an acutely reduced arterial O2 content (hypoxemia) , normal O2 delivery to the tissues can be maintained by which of the following?

When using therapeutic agents that can cause methemoglobinemia (methHb) , which of the following is important to prevent adverse effects?

On what does the movement of gases between the lungs and the body tissues mainly depend?

A patient breathing room air at sea level has the following arterial blood gases: PaO2 = 62 mm Hg; PCO2 = 75 mm Hg. When the FIO2 is raised to 0.28, the PaO2 rises to 95 mm Hg. What is the most likely cause of the hypoxemia?

The two major causes of dead space ventilation are: 1) a decreased tidal volume. 2) dysoxia. 3) impaired CO2 removal. 4) increased physiologic dead space.

Assuming a constant FiO2 and carbon dioxide production, which of the following statements is correct?

What happens when the temperature of the blood rises? 1) The Hb saturation for a given PO2 falls. 2) The HbO2 curve shifts to the right. 3) The affinity of Hb for O2 increases.

In a person breathing room air (and with all else being normal) , if the alveolar PCO₂ rises from 40 to 70 mm Hg, what would you expect?

Which of the following would you expect to find with "O₂ debt"? 1) Accentuated in diseases such as sepsis. 2) O₂ demand exceeds O₂ delivery. 3) O₂ excess usage results in debt.

As the amount of O₂ that dissolves in the plasma increases, what is it directly proportional to?

Which of the following values corresponds most closely to the normal PO₂ and PCO₂ in the mixed venous blood returning to the lungs from the right side of the heart?

The lowest PO₂ would normally be found in what location?

If the total hemoglobin content (Hb + HbO₂) of a sample of blood is 20 g/dl and the oxyhemoglobin (HbO₂) content is 15 g/dl, what is the HbO₂ saturation?

Which of the following increases the affinity of Hb for O₂? 1) Decreased 2,3-DPG 2) Decreased PCO₂ 3) Increased pH 4) Increased temperature

The oxidation of the Hb molecule's iron ions to the ferric state (Fe³⁺) results in which of the following? 1) Form of anemia called sickle cell anemia 2) Formation of methemoglobin (metHb) 3) Inability of metHb to bind with O₂

The PAO₂ depends on which of the following factors? 1) Ambient (atmospheric) pressure 2) Fractional concentration of inspired O₂ 3) Level of V_A 4) Types of fuels burned (fat, protein, and carbohydrate)

What is the minimum amount of time that blood must take for pulmonary capillary transit for equilibration of O₂ to occur across the alveolar-capillary membrane?

In the presence of an acutely reduced arterial O₂ content (hypoxemia) , normal O₂ delivery to the tissues can be maintained by which of the following?

A patient breathing room air at sea level has the following arterial blood gases: PaO₂ = 62 mm Hg; PCO₂ = 75 mm Hg. When the FIO₂ is raised to 0.28, the PaO₂ rises to 95 mm Hg. What is the most likely cause of the hypoxemia?

The two major causes of dead space ventilation are: 1) a decreased tidal volume. 2) dysoxia. 3) impaired CO₂ removal. 4) increased physiologic dead space.

Assuming a constant FiO₂ and carbon dioxide production, which of the following statements is correct?

What happens when the temperature of the blood rises? 1) The Hb saturation for a given PO₂ falls. 2) The HbO₂ curve shifts to the right. 3) The affinity of Hb for O₂ increases.