Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
The most powerful respiratory stimulus for breathing in a healthy person is ________.
loss of oxygen in tissues
increase of carbon dioxide
Unlike inspiration, expiration is a passive act because no muscular contractions are involved.
Expiration, however, depends on two factors. Which of the choices below lists those two factors?
the expansion of respiratory muscles that were contracted during inspiration and the lack of
surface tension on the alveolar wall
the negative feedback of expansion fibers used during inspiration and the outward pull of
surface tension due to surfactant
combined amount of CO2 in the blood and air in the alveoli
the recoil of elastic fibers that were stretched during inspiration and the inward pull of
surface tension due to the film of alveolar fluid
Which of the following is not possible?
The amount of gas flowing in and out of the alveoli is directly proportional to the difference
in pressure or pressure gradient between the external atmosphere and the alveoli.
Pressure gradient equals gas flow over resistance.
Resistance equals pressure gradient over gas flow.
Gas flow equals pressure gradient over resistance.
The walls of the alveoli are composed of two types of cells, type I and type II. The function of type
II is to ________.
replace mucus in the alveoli
trap dust and other debris
protect the lungs from bacterial invasion