WorksheetsEgan Ch. 12
Total questions: 35
Worksheet time: 1hrs 10mins
What is the most important component in the O2 transport system?
Dissolved O2 in ml/dl
HCO3–
Hb
PaO2
During normal inspiration, which of the following occurs?
Alveoli at the apexes expand less than those at the bases.
Alveoli at the apexes expand more than those at the bases.
Alveoli at the bases and apexes expand almost equally.
Alveoli at the bases expand less than those at the apexes.
Which condition causes an increase in alveolar dead space?
Absorption atelectasis
Blockage of pulmonary circulation
Increase in anatomic dead space
Pulmonary vasodilation
Calculate the approximate PAO2 given the following conditions (assume R = 0.8): FiO2 = .40, PB = 770 mm Hg, PACO2 = 31 mm Hg
100 mm Hg
135 mm Hg
250 mm Hg
723 mm Hg
What is the approximate normal level of carbon dioxide production (CO2) for an adult?
200 ml/min
250 ml/min
4200 ml/min
2000 ml/min
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
1, 2, 3
1, 2, 4
2, 3
All the above
What is the normal range of PAO2 – PaO2 for healthy young adults breathing room air?
5 to 10 mm Hg
10 to 20 mm Hg
20 to 30 mm Hg
50 to 60 mm Hg
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)
1, 2, 3
2, 3, 4
3, 4
all the above
The expected PaO2 for an 80-year-old man who is otherwise in good health and breathing room air is approximately what level?
50 mm Hg
75 mm Hg
80 mm Hg
90 mm Hg
When a Hb molecule accumulates excessive amounts of HCO3–, it is expelled from the cell in exchange for Cl–. What is this called?
Bohr effect
Haldane effect
Hamburger phenomenon
Hydrolysis phenomenon
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.
1, 2
2, 3
1, 3
all the above
At body temperature, how much O2 will physically dissolve in plasma at a PO2 of 40 mm Hg?
0.12 ml/dl
0.20 ml/dl
0.30 ml/dl
1.34 g/dl
A patient with a normal PaO2 and cardiac output is exhibiting signs and symptoms of tissue hypoxia. What is the most likely cause?
Hemoglobin deficiency
Low ambient PO2
Right-to-left shunt
Hypoventilation
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?
17%
50%
75%
83%
On what does the movement of gases between the lungs and the body tissues mainly depend?
Active transport
Gaseous diffusion
Membrane dialysis
Membrane transport
A patient has a whole-body O2 consumption of 320 ml/min and a measured CaO2 – CO2 of 8 ml/dl. What is the cardiac output?
3.2 L/min
4.0 L/min
5.0 L/min
7.0 L/min
What is the primary factor that maintains the pressure gradient that drives O2 from the capillaries into the interstitial spaces and into the cells?
Bohr effect on the RBC
Cellular consumption of O2
Haldane effect on the RBC
Increased carbon dioxide in blood decreasing Hb affinity for O2
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?
PAO2 to fall by approximately 30 mm Hg
PAO2 to fall by approximately 40 mm Hg
PAO2 to rise by approximately 30 mm Hg
PAO2 to rise by approximately 40 mm Hg
Which of the following statements is true regarding the Haldane effect?
At high SaO2 levels, carbon dioxide more readily forms carbamino compounds.
At high SaO2 levels, the capacity of blood to hold carbon dioxide decreases.
At high SaO2 levels, the capacity of blood to hold carbon dioxide increases.
At low SaO2 levels, the capacity of blood to hold carbon dioxide decreases.
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
1, 2
1, 3
2, 3
all the above
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
1, 2, 4
1, 2, 3
2, 4
all the above
Which of the following conditions must exist for gas to move between the alveolus and pulmonary capillary?
Adequate alveolar ventilation (VA)
Normal central nervous system (CNS) control mechanism
Sufficient amount of blood hemoglobin (Hb)
Difference in partial pressures (pressure gradient)
Which of the following equations best describes O2 delivery to the tissues?
Arterial O2 content ÷ cardiac output
Arterial O2 content X cardiac output
Cardiac output + arterial O2 content
Cardiac output X vascular resistance
The lowest PO2 would normally be found in what location?
Arterial blood
Atmospheric air
Cells
Venous blood
An abnormal metabolic state in which the tissues are unable to utilize the O2 made available to them best describes which of the following?
Diffusion hypoxia
Dysoxia
Hemic hypoxia
Physiologic shunt
What is the highest PAO2 one could expect to observe in an individual breathing room air at sea level?
90 to 100 mm Hg
110 to 120 mm Hg
640 to 670 mm Hg
710 to 760 mm Hg
In which of the following conditions will erythrocyte concentration of 2,3-DPG be decreased?
Anemia
Banked blood
High pH
Hypoxemia
Which of the following would you expect to occur if ventilation to an area of the lung remained constant but perfusion to this same area decreased?
1. The PACO2 should fall.
2. The PAO2 should fall.
3. The ratio should rise.
3
1, 2
1, 3
all the above
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?
PO2 = 40 mm Hg; PCO2 = 46 mm Hg
PO2 = 40 mm Hg; PCO2 = 100 mm Hg
PO2 = 100 mm Hg; PCO2 = 40 mm Hg
PO2 = 100 mm Hg; PCO2 = 46 mm Hg
When using therapeutic agents that can cause methemoglobinemia (methHb), which of the following is important to prevent adverse effects?
Checking the frequency of ventilation
Frequent monitoring for methHb to weigh the risk against the benefit
Occasional monitoring for sickle cell anemia
Frequent monitoring for abnormal body temperature (high or low)
According to the Fick principle, if O2 consumption remains constant, an increase in cardiac output will manifest itself as which of the following?
Decrease in the CaO2 – CO2.
Increase in the CaO2.
Increase in the CaO2 – CO2.
Decrease in the CO2.
What is the effect of an elevated intracellular 2,3-DPG concentration?
Decreases the availability of O2 to the tissues.
Increases the affinity of Hb for O2.
Increases the availability of O2 to the tissues.
Shifts the HbO2 dissociation curve to the left.
What role does the Bohr effect play in O2 transport?
Describes the effect of varying enzyme levels on Hb and O2 affinity.
Diminishes tissue oxygenation due to electrolyte imbalances.
Enhances O2 delivery to tissues and O2 pickup at lungs.
Explains the effect that O2 levels have on carbon dioxide transport.
A patient has a P50 value of 29 mm Hg. What does this indicate?
Decreased affinity of Hb for O2
Higher than normal Hb saturation for a given PO2
Increased affinity of Hb for O2
Normal position in the HbO2
Regarding pulmonary blood flow in the upright lung, which of the following statements is true?
The apexes receive approximately 20 times more blood flow than the bases.
The bases receive approximately 20 times more blood flow than the apexes.
The greatest blood flow is found at the apexes of the lungs.
The pulmonary circulation is a high-pressure system.
