Why is the total mechanical work of breathing difficult to assess during spontaneous breathing?
a. Most volunteer subjects cannot under-stand the procedure used.
b. Respiratory muscle activity contributes to inflation resistance.
c. The respiratory muscles (diaphragm, etc.) must be paralyzed.
d. The subjects used to make the measure-ments must be unconscious.
Q. 2 Which of the following formulas is used to compute the mechanical work of breathing?
a. Change in pressure/flow
b. Change in pressure change in flow
c. Change in pressure change in volume
d. Change in volume/change in pressure
Q. 3 On inspecting a volume-pressure curve of the lungs and thorax, an increase in the mechanical work of breathing above normal would always be indicated by which of the following?
a. Decrease in the area of the vol-ume-pressure curve
b. Decrease in the slope of the vol-ume-pressure curve
c. Increase in the area of the volume-pressure curve
d. Increase in the slope of the vol-ume-pressure curve
Q. 4 Most of the drop in pressure due to frictional resistance to gas flow occurs in what region?
a. Nose, mouth, and large airways
b. Respiratory bronchioles
c. Terminal bronchioles
d. Terminal respiratory unit
Q. 5 Which of the following statements about the equal pressure point (EPP) is true?
a. As gas travels from the EPP to the mouth, greater expiratory effort increases flow.
b. At the EPP, pressure inside the airway exceeds Ppl.
c. The EPP normally occurs at volumes greatly below the FRC.
d. Upstream from the EPP (toward the alve-oli), Ppl exceeds pressure in the airway.
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