Chapter 16: Pulmonary Anatomy and Physiology

Question 1

At what anatomic site does the trachea divide into the right and left mainstem bronchi?
a. Posterior larynx
b. Cricoid cartilage
c. Epiglottis
d. Major carina

Answer 1

ANS: D
The trachea is a hollow tube approximately 11 cm in length and 2.5 cm in diameter. It begins at the cricoid cartilage and ends at the bifurcation (the major carina) from which the two mainstem bronchi arise.

Question 2

Which physiologic mechanism is a passive event in a spontaneously breathing patient?
a. Coughing
b. Inhalation
c. Exhalation
d. Yawning

Answer 2

ANS: C
Inhalation involves the contraction of the diaphragm, an active event, as do yawning and coughing. Exhalation in the healthy lung is a passive event requiring very little energy

Question 3

What substance do alveolar type II cells secrete?
a. Trypsin
b. Chyme
c. Amylase
d. Surfactant

Answer 3

ANS: D
The most important function of the type II cells is their ability to produce, store, and secrete pulmonary surfactant. Trypsin and amylase are proteins used for digestion. Chyme is a semifluid mass of partly digested food that is expelled by the stomach into the duodenum.

Question 4

Which pulmonary condition is related to a lack of surfactant?
a. Pulmonary embolus
b. Pulmonary hypertension
c. Pulmonary atelectasis
d. Pulmonary edema

Answer 4

ANS: C
Surfactant is responsible for preventing the alveoli from completely collapsing on exhalation. Lack of this lipoprotein allows the alveoli to collapse, producing atelectasis. Lack of surfactant is not responsible for the other conditions.

Question 5

What is the main function of the conducting airways?
a. Gas exchange
b. Cool the inhaled air
c. Remove moisture from inhaled air
d. Prevent the entry of foreign material

Answer 5

ANS: D
The conducting airways consist of the upper airways, the trachea, and the bronchial tree. Their major functions are to warm and humidify the inhaled air, prevent the entrance of foreign matter into the gas exchange areas, and serve as a passageway for air entering and leaving the gas exchange regions of the lungs.

Question 6

A patient has sustained a stroke and is no longer able to control his epiglottis. Why should the nurse be concerned about the patient?
a. The patient is at increased risk of aspiration.
b. The patient will need surgery to close his epiglottis.
c. The patient will need a tracheostomy to breathe.
d. The patient is at risk for a pneumothorax.

Answer 6

ANS: A
The epiglottis is responsible for closing over the trachea and preventing entry of swallowed material into the lungs. An inability to control the epiglottis increases the risk of aspiration and may warrant placement of a feeding tube. The patient will still be able to breathe.
Closure of the epiglottis over the trachea will occlude the airway.

Question 7

Patients who have aspiration pneumonitis often present with right lower lobe involvement
more than left lower lobe involvement. Why does this occur?
a. The left mainstem bronchus angles down more than the right.
b. More people are right-side dominant.
c. The right mainstem bronchus angles down more than the left.
d. The right mainstem bronchus is narrower than the left.

Answer 7

ANS: C
The right bronchus is wider than the left and angles at 20 to 30 degrees from the midline. Because of this angulation and the forces of gravity, the most common site of aspiration of foreign objects is through the right mainstem bronchus into the lower lobe of the right lung.

Question 8

Which artery(s) have the lowest oxygen saturation?
a. Aorta
b. Subclavian
c. Carotid
d. Pulmonary

Answer 8

ANS: D
The pulmonary artery delivers blood from the right ventricle to the lungs, where they receive oxygen from the alveoli. The aorta, subclavian artery, and carotid artery are all supplied from the left ventricle, where the oxygen concentration is highest.

Question 9

Which range would be considered normal for pulmonary artery systolic pressures?
a. 15 to 30 mm Hg
b. 4 to 12 mm Hg
c. 25 to 35 mm Hg
d. 1 to 11 mm Hg

Answer 9

ANS: A
Pulmonary artery systolic pressure ranges from 15 to 30 mm Hg, pulmonary artery diastolic pressure ranges from 4 to 12 mm Hg, and pulmonary artery mean pressure ranges from 9 to 18 mm Hg. Pulmonary hypertensions is defined as pulmonary artery systolic pressure of greater than 35 mm Hg.

Question 10

The oxygen saturation of a healthy individual rarely reaches 100% on room air. This can best be explained by what concept?
a. Physiologic shunting
b. Alveolar capillary diffusion
c. Collateral air passages
d. Anatomic dead space

Answer 10

ANS: A
The mixing of venous blood from the bronchial circulation with the oxygenated blood in the left atrium decreases the saturation of left atrial blood to a range between 96% and 99%. This is referred to as physiologic shunting. For this reason, while a person is breathing room air, the oxygen saturation of arterial blood is less than 100%.

Question 11

Which pulmonary alteration increases the work of breathing in the patient with emphysema?
a. Decreased lung recoil
b. Decreased chest wall compliance
c. Increased lung compliance
d. Increased airway resistance

Answer 11

ANS: A
Emphysema results in destruction and enlargement of the alveoli, leading to decreased lung recoil and increased work of breathing. Emphysema results in decreased lung compliance not increased compliance. Emphysema does not affect chest wall compliance or airway resistance.

Question 12

What anatomic regions are considered physiologic dead space?
a. Respiratory bronchiole and unperfused alveoli
b. Trachea and perfused alveoli
c. Trachea and unperfused alveoli
d. Trachea and mainstem bronchi

Answer 12

ANS: C
Respiratory bronchioles participate in gas exchange. The areas in the lungs that are ventilated but in which no gas exchange occurs are known as dead space regions (trachea and mainstem bronchi). These unperfused alveoli are known as alveolar dead space. Anatomic dead space plus alveolar dead space is called physiologic dead space.

Question 13

If a patient sustained an injury to the apneustic center in the lower pons area, in which area should the nurse most expect the patient to exhibit problems?
a. Respiratory rate
b. Triggering exhalation
c. Respiratory rhythm
d. Depth of respiration

Answer 13

ANS: D
The apneustic center in the lower pons is thought to work with the pneumotaxic center to regulate the depth of inspiration. The pneumotaxic center in the pons is responsible for limiting inhalation and triggering exhalation. This response also facilitates control of the rate and pattern of respiration. The ventral respiratory group, located in the medulla, is responsible for inspiration and expiration during periods of increased ventilation.

Question 14

Normally, which central chemoreceptor is responsible for triggering ventilation changes?
a. Increased PaCO2
b. Increased HCO3¯
c. Decreased PaO2
d. Increased PaO2

Answer 14

ANS: A
Ventilation increases when the hydrogen ion concentration increases and decreases when the hydrogen ion concentration decreases. An increase in the partial pressure of carbon dioxide (PaCO2 ) causes the movement of carbon dioxide across the blood–brain barrier into the
cerebrospinal fluid, stimulating the movement of hydrogen ions into the brain’s extracellular fluid. Peripheral chemoreceptors respond to changes in PaO2 levels.

Question 15

Which V/Q ratio would most suggest intrapulmonary shunting?
a. 0.8
b. 2.2
c. 0.4
d. 0.9

Answer 15

ANS: C
A V/Q ratio of 4:5 or 0.8 is considered normal. A V/Q less than 0.8 is considered shunt producing, and a V/Q greater than 0.8 is considered dead space producing.

Question 16

A shift to the left of the oxyhemoglobin dissociation curve would cause which physiologic
alteration?
a. Better tissue perfusion
b. Lower SpO2
c. Decreased hemoglobin affinity for O2
d. Impaired tissue oxygen delivery

Answer 16

ANS: D
When the curve is shifted to the left, there is a higher arterial saturation for any given PaO2 because hemoglobin has an increased affinity for oxygen. Although the saturation is higher, oxygen delivery to the tissues is impaired because hemoglobin does not unload as easily.

Question 17

A patient in diabetic ketoacidosis would exhibit what alteration to the pulmonary system?
a. Breathe faster to increase pH
b. Breathe slower to increase pH
c. Breathe faster to decrease pH
d. Breathe slower to decrease pH

Answer 17

ANS: C
Breathing faster increases the expiration of CO2 , which results in less acid in the bloodstream and a decreased pH.

Question 18

What are the primary functions of the pulmonary system?
a. Gas exchange and the movement of air in and out of the lungs
b. Gas exchange and the transfer of oxygen to the tissues
c. The movement of blood in and out of the lungs
d. Gas exchange and the prevention of infections

Answer 18

ANS: A
The primary functions of the pulmonary system are ventilation and respiration. Ventilation is the movement of air in and out of the lungs. Respiration is the process of gas exchange, that is, the movement of oxygen from the atmosphere into the bloodstream and the movement of carbon dioxide from the bloodstream into the atmosphere.

Question 19

Which part of the pulmonary anatomy does most of the work of breathing?
a. Pleura
b. Intercostal muscles
c. Diaphragm
d. Sternocleidomastoid

Answer 19

ANS: C
The main muscle of inhalation is the diaphragm. It is connected to the sternum, ribs, and vertebrae. During normal, quiet breathing, the diaphragm does approximately 80% of the work of breathing. The most important of these are the external intercostal muscles, which elevate the ribs and expand the chest cage outward. The scalene, anterior serratus, and sternocleidomastoid muscles also participate to elevate the first two ribs and sternum.

Question 20

Which statement best describes the left bronchus?
a. The left bronchus has a slight angle of 20 to 30 degrees from the midline.
b. The two mainstem bronchi are structurally and functionally similar.
c. The left bronchus is slightly narrower.
d. The bronchi are the end units of the bronchial tree.

Answer 20

ANS: C
The two mainstem bronchi are structurally different. The right bronchus is wider and angles at 20 to 30 degrees from the midline. The right mainstem bronchus is the most common site of aspiration of foreign objects. The left bronchus is slightly narrower than the right, and because of its position above the heart, the left bronchus angles directly toward the left lung at approximately 45 to 55 degrees from the midline

Question 21

What is the most important function of type I alveolar epithelial cells?
a. They comprise 90% of total alveolar surface in the lungs for gas exchange.
b. The ability to produce, store, and secrete pulmonary surfactant.
c. The ability to trap foreign particles for auto digestion.
d. The maintenance, repair, and restoration of the mucociliary escalator.

Answer 21

ANS: A
Type I alveolar epithelial cells comprise approximately 90% of the total alveolar surface within the lungs. The most important function of the type II cells is their ability to produce, store, and secrete pulmonary surfactant.

Question 22

Which statement describes the relationship between the pulmonary circulation and the pulmonary vascular bed?
a. The pulmonary circulation is a high-pressure system with normal pressures
averaging 100/60 to 120/70 mm Hg.
b. Because of the low pulmonary arterial pressures, the right ventricular wall
thickness needs to be only one-third that of the left ventricle.
c. Pulmonary hypertension is defined as increased pulmonary artery systolic pressure
above 20 mm Hg.
d. The most common cause of pulmonary hypertension is right-sided heart failure.

Answer 22

ANS: B
Because of low pulmonary artery pressures, right ventricular wall thickness needs to be only approximately one-third of left ventricular wall thickness. Pulmonary hypertension is defined as increased pressure (pulmonary artery systolic greater than 35 mm Hg and pulmonary artery mean less than 25 mm Hg at rest or less than 30 mm Hg with exertion) within the pulmonary arterial system. Pulmonary hypertension increases the afterload of the right ventricle and, when chronic, can result in right ventricular hypertrophy (cor pulmonale) and failure.

Question 23

Oxygen saturation of left atrial blood is normally between 96% and 99%. What is the explanation for less than 100% saturation?
a. As blood passes to the alveolar–capillary membrane, a predicted percentage of hemoglobin will not bind with oxygen.
b. During normal respiration, the majority of alveoli are not expanded.
c. Venous blood from the bronchial circulation is returned to the left atrium.
d. A small amount of blood leaks from the right atrium to the left atrium with each ventricular contraction.

Answer 23

ANS: C
Venous blood from the bronchial circulation returns directly into the left atrium. The mixing of venous blood decreases the saturation of left atrial blood to a range between 96% and 99%.

Question 24

What is the movement of air into and out of the lungs termed?
a. Ventilation
b. Respiration
c. Diffusion
d. Perfusion

Answer 24

ANS: A
Ventilation is the movement of air into and out of the lungs and is distinct from respiration, which refers to gas exchange, not movement by air. Respiration is the process of gas
exchange by means of movement of oxygen from the atmosphere into the bloodstream and movement of carbon dioxide from the bloodstream into the atmosphere. Diffusion moves molecules from an area of high concentration to an area of low concentration. The distribution of perfusion through the lungs is related to gravity and intra-alveolar pressures.

Question 25

How much of the basal oxygen consumption is required by the pulmonary system during
normal quiet breathing?
a. 10% to 20%
b. 5% to 10%
c. 3% to 5%
d. 1% to 2%

Answer 25

ANS: D
During normal quiet ventilation, only 1% to 2% of basal oxygen consumption is required by the pulmonary system.

Question 26

What is the portion of total ventilation that participates in gas exchange termed?
a. Alveolar dead space
b. Anatomic dead space
c. Physiologic dead space
d. Alveolar ventilation

Answer 26

ANS: D
The portion of total ventilation that participates in gas exchange is known as alveolar ventilation. The areas in the lungs that are ventilated but in which no gas exchange occurs
are known as dead space regions. The conducting airways are referred to as anatomic dead space because they are ventilated but not perfused and therefore not able to participate in gas exchange. These unperfused alveoli are known as alveolar dead space. Anatomic dead space plus alveolar dead space is called physiologic dead space.

Question 27

Which physiologic alteration will stimulate the central chemoreceptors?
a. Decreased PaO2
b. Increased PaO2
c. Decreased SaO2
d. Increased PaCO2

Answer 27

ANS: D
The central chemoreceptors respond to changes in the hydrogen ion concentration of that fluid. Ventilation is increased when the hydrogen ion concentration increases, as evidenced by a rise in the plasma arterial PaCO2 .

Question 28

Which factor will increase diffusion of gases across the alveolar capillary membrane?
a. A decrease in the surface area of the membrane
b. An increase in the thickness of the membrane
c. An increase in the driving pressure of the gas
d. A decrease in the solubility coefficient of the gas

Answer 28

ANS: C
Several factors affect the rate of diffusion, including increasing the driving pressure of the gas. A decrease in surface area of the membrane, an increase in the thickness of the membrane, and a decrease in the solubility coefficient of the gas decrease diffusion of gases
across the membrane.

Question 29

Atelectasis can cause a shunt-producing ventilation-perfusion mismatch. Which pathophysiologic mechanism explains how this occurs?
a. An alveolus that is receiving perfusion exceeding ventilation
b. An alveolus that is receiving ventilation exceeding perfusion
c. An alveolus that is receiving ventilation but not perfusion
d. An alveolus that is not receiving perfusion or ventilation

Answer 29

ANS: A
A shunt-producing ventilation-perfusion mismatch is one in which perfusion exceeds ventilation. Whereas situations in which ventilation exceeds perfusion V/Q greater than 0.8 are considered to be dead space producing, situations in which perfusion exceeds ventilation V/Q less than 0.8 are considered to be shunt producing

Question 30

Which factor will result in a shift of the oxyhemoglobin dissociation curve to the left?
a. Increased PaCO2
b. Increased pH
c. Increased temperature
d. Increased 2,3-DPG

Answer 30

ANS: B
Factors shifting the curve to the left are increased pH, decreased PaCO2 , decreased temperature, and decreased 2,3-DPG.

Question 31

Which statement about methemoglobin is true?
a. Methemoglobin does not carry oxygen.
b. Methemoglobin occurs when carbon monoxide combines with hemoglobin.
c. Carbon dioxide is carried on methemoglobin.
d. Hemoglobin S is responsible for methemoglobin.

Answer 31

ANS: A
Methemoglobin occurs when the iron atoms within the hemoglobin molecule are oxidized from the ferrous state to the ferric state. Methemoglobin does not carry oxygen. The most common abnormality involving hemoglobin is a decrease in amount. This can be an acute or a chronic situation (anemia). Abnormal hemoglobin structure also can pose problems, such as hemoglobin S, which is responsible for sickle cell anemia. Hemoglobin carries approximately 97% of the total amount of oxygen held within the bloodstream.

Question 32

A patient is admitted with community-associated pneumonia. Respirations are 32 breaths/min. Temperature is 102 F (38.6 C). Based on the readings the nurse would expect the oxyhemoglobin dissociation curve to shift. What other factors would cause the curve to shift in the same direction?
a. Decreased 2,3-DPG
b. Increased pH
c. Increased CO2
d. Increased O2

Answer 32

ANS: C
The oxyhemoglobin dissociation curve will shift to the right as a result of the patient’s temperature. Other factors that cause the curve to shift to the right are decreased pH, increased CO2 , and increased 2,3-DPG. Increased O2 will not shift the curve either right or left.

Question 33

A patient is admitted with an acute exacerbation of asthma. Respirations are 28 breaths/min.
Blood gases reveal an uncompensated respiratory acidosis. The patient’s work effort for
breathing is increased due to which pathophysiologic mechanism?
a. Increased lung compliance
b. Decreased lung recoil
c. Increased chest wall compliance
d. Increased airway resistance

Answer 33

ANS: D
Pulmonary diseases that decrease lung compliance (e.g., atelectasis, pulmonary edema), decrease chest wall compliance (e.g., kyphoscoliosis), increase airway resistance (e.g., bronchitis, asthma), or decrease lung recoil (e.g., emphysema) can increase the work of breathing so much that one-third or more of the total body energy is used for ventilation.

Question 34

Based on the oxyhemoglobin dissociation curve, respiratory acidosis will have which effect?
a. A shifting of the curve to the left
b. Increased oxygen saturation
c. Enhanced oxygen delivery at the tissue level
d. Hypothermia

Answer 34

ANS: C
When the curve is shifted to the right, as occurs in acidosis, although the saturation is lower than expected, a right shift enhances oxygen delivery at the tissue level because hemoglobin unloads more readily.

Question 35

The lobes are divided into 18 segments. How many are on the right lung?
a. 3
b. 8
c. 10
d. 15

Answer 35

ANS: C
The lobes are divided into 18 segments, each of which has its own bronchus branching immediately off a lobar bronchus. Ten segments are located in the right lung and eight in the left lung.

Question 36

Which pleura adheres to the lungs?
a. Parietal
b. Visceral
c. Intrapleural
d. Surfactant

Answer 36

ANS: B
The visceral pleura adheres to the lungs, extending onto the hilar bronchi and into the major fissures. The parietal pleura lines the inner surface of the chest wall and mediastinum. The pleural space has a pressure within it called the intrapleural pressure. Surfactant is
responsible for preventing the alveoli from completely collapsing on exhalation.

Question 37

Which nerve stimulates movement of the diaphragm?
a. Musculocutaneous nerve
b. Phrenic nerve
c. Median nerve
d. Axillary nerve

Answer 37

ANS: B
The phrenic nerve arises from the cervical plexus through the fourth cervical nerve, with secondary contributions by the third and fifth cervical nerves. The other nerves control use and feeling of the arms.

Question 38

Trauma to which vertebrae will cause ventilation dysfunction?
a. C3 to C5
b. C5 to T3
c. T4 to T6
d. T7 to T10

Answer 38

ANS: A
The phrenic nerve arises from the cervical plexus through the fourth cervical nerve, with secondary contributions by the third and fifth cervical nerves. For this reason and because the diaphragm does most of the work of inhalation, trauma involving levels C3 to C5 causes
ventilation dysfunction.

Question 39

Muscles of exhalation include which of the following? (Select all that apply, one, some, or all.)
a. Abdominal
b. Diaphragm
c. External intercostals
d. Internal intercostals
e. Scalene

Answer 39

ANS: A, D
Exhalation occurs when the diaphragm relaxes and moves back up toward the lungs. The intrinsic elastic recoil of the lungs assists with exhalation. Because exhalation is a passive act, there are no true muscles of exhalation other than the internal intercostal muscles, which assist the inward movement of the ribs

Question 40

The lymphatic system plays which of the following important roles? (Select all that apply, one, some, or all.)
a. Ridding lung tissue of excess CO2
b. Connecting the thebesian veins
c. Removing fluid from the lungs
d. Producing immune responses
e. Removing cell debris from the lungs

Answer 40

ANS: C, D, E
The lymphatic system in the lungs serves two purposes. As part of the immune system, it is responsible for removing foreign particles and cell debris from the lungs and for producing both antibody and cell-mediated immune responses. It also is responsible for removing fluid from the lungs and for keeping the alveoli clear.