Respiratory System Physiology Set 1

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Physiology (Respiratory System Set 1)

1 / 25

Which person would be expected to have
the largest A–a gradient?

Person with pulmonary fibrosis

Person who is hypoventilating due to morphine overdose

Person at 12,000 feet above sea level

Person with normal lungs breathing 50% O2

Person with normal lungs breathing 100% O2

2 / 25

A person with a ventilation/perfusion
(V/Q) defect has hypoxemia and is treated
with supplemental O2. The supplemental O2
will be most helpful if the person’s predominant V/Q defect is

dead space

shunt

high V/Q

low V/Q

V/Q = 0

3 / 25

In a maximal expiration, the total volume
expired is

tidal volume (TV)

vital capacity (VC)

expiratory reserve volume (ERV)

residual volume (RV)

functional residual capacity (FRC)

4 / 25

The pH of venous blood is only slightly
more acidic than the pH of arterial blood
because

CO2 is a weak base

there is no carbonic anhydrase in venous blood

the H+ generated from CO2 and H2O is buffered by HCO3 – in venous blood

the H+ generated from CO2 and H2O is buffered by deoxyhemoglobin in venous blood

oxyhemoglobin is a better buffer for H+ than is deoxyhemoglobin

5 / 25

A 38-year-old woman moves with her
family from New York City (sea level) to
Leadville Colorado (10,200 feet above sea
level). Which of the following will occur as a
result of residing at high altitude?

Hypoventilation

Arterial PO2 greater than 100 mm Hg

Decreased 2,3-diphosphoglycerate (DPG) concentration

Shift to the right of the hemoglobin–O2 dissociation curve

Pulmonary vasodilation

6 / 25

Which of the following causes of hypoxia
is characterized by a decreased arterial PO2
and an increased A–a gradient?

Hypoventilation

Right-to-left cardiac shunt

Anemia

Carbon monoxide poisoning

Ascent to high altitude

7 / 25

A 42-year-old woman with severe
pulmonary fibrosis is evaluated by her
physician and has the following
arterial blood gases: pH = 7.48, PaO2 =
55 mm Hg, and PaCO2 = 32 mm Hg. Which
statement best explains the observed value
of PaCO2?

The increased pH stimulates breathing via peripheral chemoreceptors

The increased pH stimulates breathing via central chemoreceptors

The decreased PaO2 inhibits breathing via peripheral chemoreceptors

The decreased PaO2 stimulates breathing via peripheral chemoreceptors

he decreased PaO2 stimulates breathing via central chemoreceptors

8 / 25

In the transport of CO2 from the tissues
to the lungs, which of the following occurs in
venous blood?

Conversion of CO2 and H2O to H+ and HCO3 – in the red blood cells (RBCs)

Buffering of H+ by oxyhemoglobin

Shifting of HCO3 – into the RBCs from plasma in exchange for Cl–

Binding of HCO3 – to hemoglobin

Alkalinization of the RBCs

9 / 25

If an area of the lung is not ventilated
because of bronchial obstruction, the pulmonary capillary blood serving that area will
have a PO2 that is

equal to atmospheric PO2

equal to mixed venous PO2

equal to normal systemic arterial PO2

higher than inspired PO2

lower than mixed venous PO2

10 / 25

Which of the following changes occurs
during strenuous exercise?

Ventilation rate and O2 consumption increase to the same extent

ystemic arterial PO2 decreases to about 70 mm Hg

Systemic arterial PCO2 increases to about 60 mm Hg

Systemic venous PCO2 decreases to about 20 mm Hg

Pulmonary blood flow decreases at the expense of systemic blood flow

11 / 25

Hypoxemia produces hyperventilation
by a direct effect on the

phrenic nerve

J receptors

lung stretch receptors

medullary chemoreceptors

carotid and aortic body chemoreceptors

12 / 25

Compared with the apex of the lung, the
base of the lung has

a higher pulmonary capillary PO2

a higher pulmonary capillary PCO2

a higher ventilation/perfusion (V/Q) ratio

the same V/Q ratio

13 / 25

A healthy 65-year-old man with a tidal
volume (TV) of 0.45 L has a breathing frequency of 16 breaths/min. His arterial PCO2
is 41 mm Hg, and the PCO2 of his expired air
is 35 mm Hg. What is his alveolar ventilation?

0.066 L/min

0.38 L/min

5.0 L/min

6.14 L/min

8.25 L/min

14 / 25

Compared with the systemic circulation,
the pulmonary circulation has a............

higher blood flow

lower resistance

higher arterial pressure

higher capillary pressure

higher cardiac output

15 / 25

Which volume remains in the lungs after
a maximal expiration?

Tidal volume (TV)

Vital capacity (VC)

Expiratory reserve volume (ERV)

Residual volume (RV)

Functional residual capacity (FRC)

16 / 25

A 49-year-old man has a pulmonary
embolism that completely blocks blood flow
to his left lung. As a result, which of the following will occur?

Ventilation/perfusion (V/Q) ratio in the left lung will be zero

Systemic arterial PO2 will be elevated

V/Q ratio in the left lung will be lower than in the right lung

Alveolar PO2 in the left lung will be approximately equal to the PO2 in inspired aiAlveolar PO2 in the left lung will be approximately equal to the PO2 in inspired ai

Alveolar PO2 in the right lung will be approximately equal to the PO2 in venous blood

17 / 25

When a person is standing, blood flow in
the lungs is

equal at the apex and the base

highest at the apex owing to the effects of gravity on arterial pressurehighest at the apex owing to the effects of gravity on arterial pressure

highest at the base because that is where the difference between arterial and venous pressure is greatest

lowest at the base because that is where alveolar pressure is greater than arterial pressure

18 / 25

Which of the following is the site of highest airway resistance?

Trachea

Largest bronchi

Medium-sized bronchi

Smallest bronchi

Alveoli

19 / 25

A 35-year-old man has a vital capacity
(VC) of 5 L, a tidal volume (TV) of 0.5 L, an
inspiratory capacity of 3.5 L, and a functional residual capacity (FRC) of 2.5 L. What is
his expiratory reserve volume (ERV)?

4.5 L

3.9 L

3.6 L

3.0 L

1.5 L

20 / 25

Which volume remains in the lungs after
a tidal volume (TV) is expired?

Tidal volume (TV)

Vital capacity (VC)

Expiratory reserve volume (ERV)

Residual volume (RV)

Functional residual capacity (FRC)

21 / 25

Which of the following is true during
inspiration?

Intrapleural pressure is positive

The volume in the lungs is less than the functional residual capacity (FRC)

Alveolar pressure equals atmospheric pressureAlveolar pressure equals atmospheric pressure

Alveolar pressure is higher than atmospheric pressure

Intrapleural pressure is more negative than it is during expiration

22 / 25

A 12-year-old boy has a severe asthmatic
attack with wheezing. He experiences rapid
breathing and becomes cyanotic. His
arterial PO2 is 60 mm Hg and his PCO2 is
30 mm Hg Which of the following statements about
this patient is most likely to be true?

Forced expiratory volume/forced vital capacity (FEV1/FVC) is increased

Ventilation/perfusion (V/Q) ratio is increased in the affected areas of his lungs

His arterial PCO2 is higher than normal because of inadequate gas exchangeHis arterial PCO2 is higher than normal because of inadequate gas exchange

His arterial PCO2 is lower than normal because hypoxemia is causing him to hyperventilate

His residual volume (RV) is decreased

23 / 25

In which vascular bed does hypoxia cause
vasoconstriction?

Coronary

Pulmonary

Cerebral

Muscle

Skin

24 / 25

An infant born prematurely in gestational
week 25 has neonatal respiratory distress
syndrome. Which of the following would be
expected in this infant?

Arterial PO2 of 100 mm Hg

Collapse of the small alveoli

Increased lung compliance

Normal breathing rate

Lecithin:sphingomyelin ratio of greater than 2:1 in amniotic fluid) Lecithin:sphingomyelin ratio of greater than 2:1 in amniotic fluid

25 / 25

Which of the following lung volumes
or capacities can be measured by
spirometry

Functional residual capacity (FRC)

Physiologic dead space

Residual volume (RV)

Total lung capacity (TLC)

Vital capacity (VC)

Your score is

The average score is 44%

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