Pregunta 1
Pregunta
What is the primary function of the lungs?
Pregunta 2
Pregunta
During each cycle of normal resting ventilation, a volume of gas is moved into and out of the respiratory tract. This cyclical volume is called the:
Pregunta 3
Pregunta
Which of the following pressures vary throughout the normal breathing cycle?
Pregunta 4
Pregunta
Which of the following pressures normally remains negative (relative to atmospheric pressure) during quiet breathing?
Pregunta 5
Pregunta
Which of the following pressure gradients is responsible for the actual flow of gas into and out of the lungs during breathing?
Respuesta
-
transthoracic pressure gradient (Ppl – Pbs)
-
transrespiratory pressure gradient (Palv – Pao)
-
transpulmonary pressure gradient (Palv – Ppl)
-
transcanadian pressure gradient (Ppc – Pks)
Pregunta 6
Pregunta
Which of the following pressure gradients is responsible for maintaining alveolar inflation?
Respuesta
-
transrespiratory pressure gradient (Palv – Pao)
-
transcanadian pressure gradient (Pca – Pks)
-
transthoracic pressure gradient (Ppl –Pbs)
-
transpulmonary pressure gradient (Palv – Ppl)
Pregunta 7
Pregunta
Which of the following statements about alveolar pressure (Palv) during normal quiet breathing is true?
Respuesta
-
It always remains less than atmospheric pressure.
-
It is negative during inspiration and positive during expiration.
-
It is the same as intrapleural pressure (Ppl).
-
It is positive during inspiration and negative during expiration.
Pregunta 8
Pregunta
What happens during normal inspiration?
Respuesta
-
Palv drops below that at the airway opening.
-
The transpulmonary pressure gradient widens.
-
The Ppl decreases further below atmospheric.
Pregunta 9
Pregunta
During normal tidal ventilation, the transpulmonary pressure gradient (Palv – Ppl) reaches its maximum value at what point in the cycle?
Respuesta
-
mid-expiration
-
end-inspiration
-
end-expiration
-
mid-inspiration
Pregunta 10
Pregunta
During expiration, why does gas flow out from the lungs to the atmosphere?
Respuesta
-
Airway pressure is greater than Palv.
-
Palv is greater than at the airway opening.
-
Palv is the same as at the airway opening
-
Palv is less than at the airway opening.
Pregunta 11
Pregunta
What forces must be overcome to move air into the respiratory system?
Pregunta 12
Pregunta
What term is used to note the difference between inspiratory lung volume and expiratory lung volume at any given pressure?
Pregunta 13
Pregunta
What is the effect of surface tension forces in the air-filled lung?
Respuesta
-
It decreases the lung's elasticity as volume increases
-
It makes the lung harder to inflate than if it were filled with fluid
-
It increases the elastic recoil of the lung (promoting collapse).
Pregunta 14
Pregunta
The presence of surfactant in the alveoli tends to do which of the following?
Respuesta
-
increase resistance
-
increase elastance
-
decrease surface tension
-
decrease compliance
Pregunta 15
Pregunta
How is compliance computed?
Respuesta
-
change in volume/change in pressure
-
change in volume/change in flow
-
change in pressure/change in volume
-
change in pressure/change in flow
Pregunta 16
Pregunta
Normal lung compliance is approximately which of the following?
Respuesta
-
10.00 L/cm H2O
-
2.00 L/cm H2O
-
0.20 L/cm H2O
-
0.01 L/cm H2O
Pregunta 17
Pregunta
A lung that loses elastic fibers (as in emphysema) would exhibit which of the following characteristics?
Respuesta
-
increased pulmonary compliance
-
increased airway resistance
-
decreased pulmonary vascular resistance
-
decreased airways resistance
Pregunta 18
Pregunta
A fibrotic lung would exhibit which of the following characteristics?
Respuesta
-
decreased surface tension
-
decreased PVR
-
decreased lung compliance
-
decreased airway resistance
Pregunta 19
Pregunta
What occurs at a lung volume equivalent to the functional residual capacity (FRC)?
Respuesta
-
Opposing chest-wall-lung forces generate negative Ppl.
-
Chest wall expansion is offset by lung contraction.
-
The forces of the chest wall and lungs are in balance.
Pregunta 20
Pregunta
At approximately what point during a maximum inspiration does the chest wall reach its natural resting level?