1. Which of the following pressures van throughout the normal breathing cycle?
I. alveolar pressure
II. body surface pressure
III. mouth pressure
IV. pleural pressure
D. I and IV
2. Which of the following pressures normally remains negative (relative to atmospheric pressure) during quiet breathing?
A. Palv
B. Ppl
C Pao
D Pbs
B. Ppl
3. Which of the following pressure gradients is responsible for the actual flow of gas into and out of the lungs during breathing?
C. transrespiratory pressure gradient (Palv – Pao)
4. Which of the following pressure gradients is responsible for maintaining alveolar intlation?
A Transpulmonary pressure gradient (Palv – Ppl)
B. Transthoracic pressure gradient (Ppl - Pbs)
C. Transcanadian pressure gradient (Ppc - Pb)
D. Transrespiratory pressure gradient (Palv – Pao)
A Transpulmonary pressure gradient (Palv – Ppl)
5. Which of the following statements about alveolar pressure (P during normal quiet breathing is true?
A. It is positive during inspiration and negative during expiration.
B. it is the same as intrapleural pressure
C It is negative during inspiration and positive during expiration.
D. It always remains less than atmospheric pressure.
C It is negative during inspiration and positive during expiration.
6. During normal tidal ventilation, the transpulmonary pressure gradient (Palv – Ppl) reaches its maximum value at what point in the cycle?
C. end-inspiration
7. During expiration why does gas flow out from the lungs to the atmosphere?
A. P is less than at the airway opening.
B. P is the same as at the airway opening.
C Palv is greater than at the airway opening.
D. Airway pressure is greater than P
C Palv is greater than at the airway opening
8. What forces must be overcome to move air into the respiratory system? I. tissue movement
II. elastic forces of lung tissue
III. airway resistance
IV. surface tension forces
C. I, II, III, and IV
9. What term is used to note the difference between inspiratory lung volume and expiratory lung volume at any given pressure?
A, alveolar aphasia
B. hysteresis
C. pleural pressure variance
D. transpulmonary pressures
B. hysteresis
10. The presence of surfactant in the alveoli tends to do which of the following?
A. decrease surface tension
11. How is compliance computed?
C. change in volume/change in pressure
12. Normal lung compliance is approximately which of the following?
D. 0.20 L/cm H
13. A lung that loses elastic fibers (as in emphysema) would exhibit which of the
following characteristics?
D. increased pulmonary compliance
14. A fibrotic lung would exhibit which of the following characteristics?
D. decreased lung compliance
15. Total lung—thorax compliance in normal subjects is about what level?
B. 0.1 L/cmH
16. How is airway resistance (Raw) computed?
B. change in pressure/flow
17. Normal Raw is approximately which of the following?
A. 0.5 to 2.5 cm H
18. Which of the following factors affects Raw?
I. pattern of gas flow (e.g., laminar versus turbulent)
II. characteristics of the gas being breathed
III. diameter and length of the airways
IV. variations in surrounding lung compliance from auto-PEEP
B. I, II, III, and IV
19. According to Poiseuille’s law, which of the following statements are true if we wish to maintain a constant flow of gases?
C. Halving the tube radius will require a 16-time increase in driving pressure.
20. Most of the drop in pressure due to frictional resistance to gas flow occurs in what region?
D. nose, mouth, and large airways
21. traditional physical terms, how is work defined?
A force x distance
B. force x time
C. mass x acceleration
D. mass x force
A force x distance
22. Which of the following formulas is used to compute the mechanical work of breathing?
C. change in pressure x change in volume
23. In a normal individual, what is the oxygen cost of breathing as a percentage of the body’s total oxygen consumption?
B. 75%
24. Regional factors affecting the distribution of gas in the normal lung result in which of
the following?
C. More ventilation goes to the bases and lung periphery.
25. During normal inspiration, which of the following occurs?
D. Alveoli at the apexes expand less than those at the bases.
26. Given a constant resistance, how will increasing the compliance of a lung unit alter gas movement into and out of the alveolus?
A. Both filling and emptying will be slower.
27. Which of the following statements apply to a lung unit with higher resistance than normal?
B. There will be less volume change for a given pressure change.
28. Which of the following formulas are used to compute the time constant of a lung unit?
D. resistance x compliance
29. Which of the following lung units would empty and fill most slowly?
D. a unit with high resistance and high compliance
30. If a patient has a VT of 370 ml and a respiratory rate of 20 breaths per minute, what is
the minute ventilation?
C. 7.40 L/min
31. A patient has a VT of 625 ml and a physiological dead space of 275 ml and is breathing at a frequency of 16 per minute. What is the alveolar ventilation (VA)?
B. 5600 mil/min
32. A normal 150-lb man is breathing at a rate of 17 with a tidal volume of 450 ml. By estimation, what is his approximate alveolar ventilation?
A. 5.10L/min
33. Blockage of the pulmonary arterial circulation to a portion of the lung would cause which of the following?
A. increase in alveolar dead space
34. In what portion of the lungs does alveolar dead space normally occur?
A. apices
35. Which is the correct formula to calculate the alveolar minute ventilation of a spontaneously breathing subject?
B. f x (VT - VDsphys)
36. In clinical practice measuring the physiologic dead space ventilation is achieved by using which formula?
B. modified Bohr equation
37. In normal individuals, approximately what fraction of the VT is wasted ventilation (does not participate in gas exchange)?
D. 1/3
38. Which of the following diseases or disorders is most likely to result in an increased
Vd/VT ratio?
B. pulmonary embolus
39. What will happen if the rate of breathing increases without any change in total minute ventilation
C. The VA per minute will decrease.
40. Which of the following ventilatory patterns would result in the MOST wasted ventilation per minute (assume constant physiologic dead space)?
Frequency Tidal Volume
C. 30 170
41. How can the body effectively compensate for an increased V
A. increased tidal volume
42. Under resting metabolic conditions, how much carbon dioxide does a normal adult produce per minute?
B. 200 ml/min
43. Hypoventilation is defined as:
B. elevated blood carbon dioxide level
44. A patient has a PCO of 56 mm Hg. Based on this information, what can be concluded?
B. The patient is hypoventilating.
45. Given a constant carbon dioxide production, how will changing the level of VA affect the PaCO
D. An increase in VA will decrease PaCO
46. What is ventilation in excess of metabolic needs called?
A. hyperpnea
B hyperventilation
C. hypopnea
D. hypoventilation
B hyperventilation
47. What is the single best indicator of the adequacy or effectiveness of VA?
A. Pa02
B. PAO2
C PaCO2
D.VT
