Pathophysiology: Chapter 35: Structure and Function of the Pulmonary System

Question 1

What pulmonary defense mechanism propels a mucous blanket that entraps particles
moving toward the oropharynx?
a. Nasal turbinates 
b. Alveolar macrophages 
c. Cilia
d. Irritant receptors on the nares

Answer 1

ANS: C
The submucosal glands of the bronchial lining produce mucus, contributing to the mucous
blanket that covers the bronchial epithelium. The ciliated epithelial cells rhythmically beat
this mucous blanket toward the trachea and pharynx, where it can be swallowed or
expectorated by coughing. This selection is the only option that accurately identifies the
pulmonary defense mechanism described.

Question 2

Which term is used to identify the movement of gas and air into and out of the lungs?

a. Perfusion c. Respiration
b. Ventilation d. Diffusion

Answer 2

ANS: B
Of the options available, ventilation is the only term used to identify the mechanical
movement of gas or air into and out of the lungs.

Question 3

When an individual aspirates food particles, where would the nurse expect to hear
decreased or absent breath sounds?
a. Left lung c. Trachea
b. Right lung d. Carina

Answer 3

ANS: B
The right mainstem bronchus extends from the trachea more vertically than the left main
bronchus; therefore aspirated fluids or foreign particles tend to enter the right lung rather
than the left or any of the other locations listed.

Question 4

Aspiration is most likely to occur in the right mainstem bronchus because it:

a. Extends vertically from the trachea.
b. Is narrower than the left mainstem bronchus.
c. Comes into contact with food and drink first.
d. Is located at the site where the bronchi bifurcate.

Answer 4

ANS: A
The right mainstem bronchus extends from the trachea more vertically than the left
mainstem bronchus; therefore aspirated fluids or foreign particles tend to enter the right
lung rather than the left. The size of both mainstems is equal. The trachea comes into
contact with food and drink first, and the carina is the site where the bronchi bifurcate.

Question 5

Air passage among alveoli is collateral and evenly distributed because of the function of
which structures?
a. Type I alveolar cells c. Acinus pores
b. Pores of Kohn d. Alveolar pores

Answer 5

ANS: B
Tiny passages called pores of Kohn permit some air to pass through the septa from
alveolus to alveolus, promoting collateral ventilation and even distribution of air among
the alveoli. This selection is the only option that accurately describes the function that
allows air passage among alveoli.

Question 6

Where in the lung does gas exchange occur?

a. Trachea c. Alveolocapillary membrane
b. Segmental bronchi d. Main bronchus

Answer 6

ANS: C

Gas exchange occurs only across the alveolocapillary membrane.

Question 7

Surfactant produced by type II alveolar cells facilitates alveolar distention and ventilation
by which mechanism?
a. Decreasing thoracic compliance
b. Attracting water to the alveolar surface
c. Decreasing surface tension in the alveoli
d. Increasing surface tension in the alveoli

Answer 7

ANS: C
Surfactant, a lipoprotein produced by type II alveolar cells, has a detergent-like effect that
separates the liquid molecules, thereby decreasing alveolar surface tension. This selection
is the only option that accurately describes the mechanism that allows surfactant to
facilitate alveolar distention and ventilation.

Question 8

Which part of the brainstem provides basic automatic rhythm of respiration by sending
efferent impulses to the diaphragm and intercostal muscles?
a. Dorsal respiratory group (DRG) c. Pneumotaxic center
b. Ventral respiratory group d. Apneustic center

Answer 8

ANS: A
The basic automatic rhythm of respiration is set by the DRG, a cluster of inspiratory nerve
cells located in the medulla that sends efferent impulses to the diaphragm and inspiratory
intercostal muscles. This selection is the only option that accurately identifies the
appropriate brainstem location.

Question 9

Which structures secrete surfactant?
a. Type I alveolar cells c. Alveolar macrophages
b. Type II alveolar cells d. Stretch receptors
.

Answer 9

ANS: B
Two major types of epithelial cells appear in the alveolus. Type I alveolar cells provide
structure, and type II alveolar cells secrete surfactant, a lipoprotein that coats the inner
surface of the alveolus and facilitates its expansion during inspiration, lowers alveolar
surface tension at end-expiration, and thereby prevents lung collapse. Neither alveolar
macrophages nor stretch receptors secrete surfactant

Question 10

Which structure is not associated with any lymphatic vessels?

a. Trachea c. Acinus
b. Bronchi d. Terminal bronchioles

Answer 10

ANS: C
No lymphatic structures are located in the acinus. The other options are associated with
lymphatic vessels.

Question 11

Which describes the pressure in the pleural space?

a. Atmospheric c. Above atmospheric
b. Below atmospheric d. Variable

Answer 11

ANS: B
Pressure in the pleural space is usually negative or subatmospheric (−4 to −10 mm Hg).
This selection is the only option that accurately describes pleural space pressure.

Question 12

The adequacy of a person’s alveolar ventilation is assessed best by monitoring which
mechanism?
a. Ventilatory rate c. Respiratory effort
b. Ventilatory pattern d. Arterial blood gas

Answer 12

ANS: D
Observation of the ventilatory rate, pattern, or effort cannot determine the adequacy of
alveolar ventilation. If a health care professional needs to determine the adequacy of
ventilation, then an arterial blood gas analysis must be performed to measure partial
pressure of arterial carbon dioxide (PaCO2).

Question 13

Which normal physiologic change occurs in the aging pulmonary system?

a. Decreased flow resistance c. Stiffening of the chest wall
b. Fewer alveoli d. Improved elastic recoil

Answer 13

ANS: C
Normal alterations include (1) loss of elastic recoil, (2) stiffening of the chest wall, (3)
alterations in gas exchange, and (4) increases in flow resistance (see Figure 34-18). The
number of alveoli is not affected by age.

Question 14

How is most of the oxygen in the blood transported?
a. Dissolved in plasma c. In the form of carbon dioxide (CO2)
b. Bound to hemoglobin d. Bound to protein
.

Answer 14

ANS: B
Oxygen is transported in the blood in two forms. A small amount dissolves in plasma, and
the remainder binds to hemoglobin molecules. The other options are not involved in this
process

Question 15

Stretch receptors and peripheral chemoreceptors send afferent impulses regarding
ventilation to which location in the brain?
a. Pneumotaxic center in the pons
b. Apneustic center in the pons
c. Dorsal respiratory group (DRG) in the medulla oblongata
d. Ventral respiratory group (VRG) in the medulla oblongata

Answer 15

ANS: C
The respiratory center is made up of several groups of neurons located bilaterally in the
brainstem: the DRG, the VRG, the pneumotaxic center, and the apneustic center. Of the
options available, only the DRG group in the medulla oblongata receives afferent impulses
in the situation described.

Question 16

Which substances cause airway epithelium to constrict?

a. Epinephrine and acetylcholine c. Bradykinin and thromboxane A
b. Histamine and prostaglandin d. Leukotrienes and prostacyclin

Answer 16

ANS: B
Constriction occurs if the irritant receptors in the airway epithelium are stimulated by
irritants in inspired air, by endogenous substances (e.g., histamine, serotonin,
prostaglandins), by many drugs, and by humoral substances. Of the options available, only
histamine and prostaglandin cause constriction.

Question 17

If a patient develops acidosis, the nurse would expect the oxyhemoglobin dissociation
curve to react in which manner?
a. Shift to the right, causing more oxygen (O2) to be released to the cells
b. Shift to the left, allowing less O2 to be released to the cells
c. Show no change, allowing the O2 concentration to remain stable
d. Show dramatic fluctuation, allowing the O2 concentration to increase

Answer 17

ANS: A
A shift to the right depicts hemoglobin’s decreased affinity for O2 or an increase in the
ease with which oxyhemoglobin dissociates and O2 moves into the cells. The
oxyhemoglobin dissociation curve is shifted to the right by acidosis (low pH) and
hypercapnia (increased partial pressure of arterial carbon dioxide [PaCO2]). This selection
is the only option that accurately identifies what will happen to the oxyhemoglobin
dissociation curve if acidosis occurs.

Question 18

How is most carbon dioxide (CO2) in the blood transported?

a. Attached to oxygen c. Combined with albumin
b. In the form of bicarbonate d. Dissolved in the plasma

Answer 18

ANS: B
Approximately 60% of the CO2 in venous blood and 90% of the CO2 in arterial blood are
carried in the form of bicarbonate.

Question 19

The sternocleidomastoid and scalene muscles are referred to as which group?

a. Diaphragmatic muscles c. Intercostal muscles
b. Muscles of expiration d. Muscles of inspiration

Answer 19

ANS: A
The accessory muscles of inspiration are the sternocleidomastoid and scalene muscles.
These muscles are not associated with the other options.

Question 20

An increase in surface tension caused by decreased surfactant production results in which
alteration?
a. Decrease in alveolar macrophage production
b. Increase in lung compliance
c. Decrease in alveoli collapse
d. Increase in alveoli fluid collection

Answer 20

ANS: D
The decrease in surface tension caused by surfactant is also responsible for keeping the
alveoli free of fluid. In the absence of surfactant, the surface tension tends to attract fluid
into the alveoli. If surfactant production is disrupted or surfactant is not produced in
adequate quantities, then the alveolar surface tension increases, causing alveolar collapse,
decreased lung expansion, increased work of breathing, and severe gas-exchange
abnormalities. The decrease in surface tension caused by surfactant is also responsible for
keeping the alveoli free of fluid. The remaining options are not associated with decreased
surfactant production.

Question 21

Decreased lung compliance means that the lungs are demonstrating which characteristic?

a. Difficult deflation c. Stiffness
b. Easy inflation d. Inability to diffuse oxygen

Answer 21

ANS: C
A decrease in compliance indicates that the lungs or chest wall is abnormally stiff or
difficult to inflate. This selection is the only option that accurately identifies the meaning
of decreased compliance.

Question 22

The lung is innervated by the parasympathetic nervous system via which nerve?

a. Vagus c. Brachial
b. Phrenic d. Pectoral

Answer 22

ANS: A
Fibers of the parasympathetic division of the autonomic nervous system (ANS) travel only
in the vagus nerve to the lung.

Question 23

What event is characteristic of the function in Zone 1 of the lung?
a. Blood flow through the pulmonary capillary bed increases in regular increments.
b. Alveolar pressure is greater than venous pressure but not greater than arterial
pressure.
c. The capillary bed collapses, and normal blood flow ceases.
d. Blood flows through Zone 1, but it is impeded to a certain extent by alveolar
pressure.

Answer 23

ANS: C
Alveolar pressure exceeds pulmonary arterial and venous pressures in Zone 1. The
capillary bed collapses, and normal blood flow ceases. Zone II is the portion where
alveolar pressure is greater than venous pressure but not greater than arterial pressure.
Blood flows through zone II, but it is impeded to a certain extent by alveolar pressure.
Zone II is normally above the level of the left atrium. In zone III, arterial and venous
pressures are greater than alveolar pressure and blood flow is not affected by alveolar
pressure. Zone III is in the base of the lung. Blood flow through the pulmonary capillary
bed increases in regular increments from the apex to the base.

Question 24

Hypoventilation that results in the retention of carbon dioxide will stimulate which
receptors in an attempt to maintain a normal homeostatic state?
a. Irritant receptors c. Peripheral chemoreceptors
b. Central chemoreceptors d. Stretch receptors

Answer 24

ANS: B
Central chemoreceptors indirectly monitor arterial blood by sensing changes in the pH of
cerebrospinal fluid (CSF). The central chemoreceptors are sensitive to very small changes
in the pH of CSF (equivalent to a 1 to 2 mm Hg change in partial pressure of carbon
dioxide [PCO2]) and are able to maintain a normal partial pressure of arterial carbon
dioxide (PaCO2) under many different conditions, including strenuous exercise. This
selection is the only option that accurately identifies the receptors that are associated with
the retention of carbon dioxide.

Question 25

What is the most important cause of pulmonary artery constriction?

a. Low alveolar partial pressure of arterial oxygen (PaO2)
b. Hyperventilation
c. Respiratory alkalosis
d. Epinephrine

Answer 25

ANS: A

The most important cause of pulmonary artery constriction is a low alveolar PaO2.

Question 26

Where does the tracheal bifurcation occur?

a. Larynx c. Carina
b. Bronchi d. Nasopharynx

Answer 26

ANS: C
The trachea, which is supported by U-shaped cartilage, connects the larynx to the bronchi,
the conducting airways of the lungs. The trachea divides into the two main airways, or
bronchi, at the carina (see Figure 34-1). The division occurs only at the carina.

Question 27

How low must the partial pressure of arterial oxygen (PaO2) drop before the peripheral
chemoreceptors influence ventilation?
a. Below 100 mm Hg c. Below 70 mm Hg
b. Below 80 mm Hg d. Below 60 mm Hg

Answer 27

ANS: C
The PaO2 must drop well below normal (to approximately 60 mm Hg) before the
peripheral chemoreceptors have much influence on ventilation.

Question 28

Which receptors are located in the smooth muscles of airways?

a. Central chemoreceptors c. Peripheral chemoreceptors
b. Stretch receptors d. J-receptors

Answer 28

ANS: B
Of the options available, only the stretch receptors are located in the smooth muscles of
airways.

Question 29

Which receptors are located near the respiratory center?

a. Peripheral chemoreceptors c. Central chemoreceptors
b. Stretch receptors d. J-receptors

Answer 29

ANS: C
Of the options available, only the central chemoreceptors are located near the respiratory
center.

Question 30

Which receptors are located in the aortic bodies, aortic arch, and carotid bodies?

a. Central chemoreceptors c. J-receptors
b. Stretch receptors d. Peripheral chemoreceptors

Answer 30

ANS: D
Of the options available, only the peripheral chemoreceptors are located in the aortic
bodies, aortic arch, and carotid bodies at the bifurcation of the carotids, near the
baroreceptors.

Question 31

What is the purpose of the spirometry measurement?

a. To evaluate the cause of hypoxia
b. To measure the volume and flow rate during forced expiration
c. To measures the gas diffusion rate at the alveolocapillary membrane
d. To determine pH and oxygen and carbon dioxide concentrations

Answer 31

ANS: B
Spirometry measures volume and flow rate during forced expiration. The alveolar-arterial
oxygen gradient is used to evaluate the cause of hypoxia. Diffusing capacity is a measure
of the gas diffusion rate at the alveolocapillary membrane. Arterial blood gas analysis can
be used to determine pH and oxygen and carbon dioxide concentrations.