Respiratory Physiology
483
Chapter 13 Test Questions
(Answers appear in Appendix A.)
1. If
P
atm
= 0 mmHg and
P
alv
= –2 mmHg, then
a. transpulmonary pressure (
P
tp
) is 2 mmHg.
b. it is the end of the normal inspiration and there is no air fl ow.
c. it is at the end of the normal expiration and there is no air fl ow.
d. transpulmonary pressure (
P
tp
) is –2 mmHg.
e. air is fl
owing into the lung.
2. Transpulmonary pressure (
P
tp
) increases by 2 mmHg during a
normal inspiration. In subject A, 500 ml of air is inspired. In
subject B, 250 ml of air is inspired for the same change in
P
tp
.
Which is true?
a. The compliance of the lung of subject B is less than that of
subject A.
b. The airway resistance of subject A is greater than that of
subject B.
c. The surface tension in the lung of subject B is less than that
in subject A.
d. The lung of subject A is defi cient in surfactant.
e. The compliance cannot be estimated from the data provided.
3. If alveolar ventilation is 4200 ml/min, respiratory frequency is
12 breaths per minute, and tidal volume is 500 ml, what is the
anatomic dead-space ventilation?
a. 1800 ml/min
b. 6000 ml/min
c. 350 ml/min
d. 1200 ml/min
e. It cannot be determined from the data provided.
4. Which of the following will increase alveolar
P
O
2
?
a. Increase in metabolism and no change in alveolar ventilation
b. Breathing air with 15 percent oxygen at sea level
c. Increase in alveolar ventilation matched by an increase in
metabolism
d. Increased alveolar ventilation with no change in metabolism
e. Carbon monoxide poisoning
5. Which of the following will cause the largest increase in
systemic arterial oxygen saturation in the blood?
a. An increase in red cell concentration (hematocrit) of 20
percent
b. Breathing 100 percent O
2
in a normal subject at sea level
c. An increase in arterial
P
O
2
from 40 to 60 mmHg
d. Hyperventilation in a healthy subject at sea level
e. Breathing a gas with 5 percent CO
2
, 21 percent O
2
, and 74
percent N
2
at sea level
6. In arterial blood with a
P
O
2
of 60 mmHg, which of the
following situations will result in the lowest blood oxygen
saturation?
a. decreased DPG with normal body temperature and blood pH
b. elevated body temperature, acidosis, and increased DPG
c. decreased body temperature, alkalosis, and increased DPG
d. normal body temperature with alkalosis
e. elevated body temperature with alkalosis
7. Which of the following is
not
true about asthma?
a. The basic defect is chronic airway infl ammation.
b. It is always caused by an allergy.
c. The airway smooth muscle is hyperresponsive.
d. It can be treated with inhaled steroid therapy.
e. It can be treated with bronchodilator therapy.
8. Which of the following is true?
a. Peripheral chemoreceptors increase fi ring with low arterial
P
O
2
but are not sensitive to an increase in arterial
P
CO
2
.
b. The primary stimulus to the central chemoreceptors is low
arterial
P
O
2
.
c. Peripheral chemoreceptors increase fi ring during a metabolic
alkalosis.
d. The increase in ventilation during exercise is due to a
decrease in arterial
P
O
2
.
e. Peripheral and central chemoreceptors both increase fi ring
when arterial
P
CO
2
increases.
9. Ventilation-perfusion inequalities lead to hypoxemia because
a. the relationship between
P
CO
2
and the content of CO
2
in
blood is sigmoidal.
b. a decrease in ventilation-perfusion matching in a lung region
causes pulmonary arteriolar vasodilation in that region.
c. increases in ventilation cannot fully restore O
2
content in
areas with low ventilation-perfusion matching.
d. increases in ventilation cannot normalize
P
CO
2
.
e. pulmonary blood vessels are not sensitive to changes in
P
O
2
.
10. After the expiration of a normal tidal volume, a subject breathes
in as much air as possible. The volume of air inspired is the
a. inspiratory reserve volume.
b. vital capacity.
c. inspiratory capacity.
d. total lung capacity.
e. functional residual capacity.
Chapter 13 Quantitative and Thought Questions
(Answers appear in Appendix A.)
1. At the end of a normal expiration, a person’s lung volume is
2 L, his alveolar pressure is 0 mmHg, and his intrapleural
pressure is –4 mmHg. He then inhales 800 ml, and at the
end of inspiration the alveolar pressure is 0 mmHg and the
intrapleural pressure is –8 mmHg. Calculate this person’s lung
compliance.
2. A patient is unable to produce surfactant. To inhale a normal
tidal volume, will her intrapleural pressure have to be more or
less subatmospheric during inspiration, relative to a healthy
person?
3. A 70-kg adult patient is artifi cially ventilated by a machine
during surgery at a rate of 20 breaths/min and a tidal volume of
250 ml/breath. Assuming a normal anatomic dead space of 150
ml, is this patient receiving an adequate alveolar ventilation?
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