Deck 13: A--The Respiratory System

Question 1

A transmural pressure gradient exists across the lung wall because the ____ pressure is less than the ____ pressure.

A) intrapleural; intra-alveolar
B) intra-alveolar; intrapleural
C) intrapleural; atmospheric
D) atmospheric; intra-alveolar
E) none of these

Answer 1

A

Question 2

The lungs are held against the thoracic wall due to

A) the negative intrapleural pressure
B) the positive intrapulmonary pressure
C) cohesiveness of the pleural fluids
D) the negative intrapleural pressure and cohesiveness of the pleural fluids
E) all of these

Answer 2

E

Question 3

Which activity below is not a respiratory event?

A) Carbon dioxide is exchanged in the alveoli.
B) Cells produce nitrogen by their metabolism.
C) Gas exchange between tissues and the blood.
D) Oxygen is exchanged in the alveoli.
E) Pulmonary ventilation.

Answer 3

B

Question 4

Inspiratory events occur because

A) The air pressure in the alveoli is greater than that of the atmosphere.
B) The air pressure in the alveoli is less than that of the atmosphere.
C) The volume of the thoracic cavity increases.
D) The air pressure in the alveoli is greater than that of the atmosphere, and the volume of the thoracic cavity increases.
E) The air pressure in the alveoli is less than that of the atmosphere, and the volume of the thoracic cavity increases.

Question 5

In addition to gas exchange, the respiratory system plays a key role in

A) enhancing venous return
B) water and temperature balance
C) body defense
D) enhancing venous return and body defense
E) all of these

Question 6

During inspiration

A) Intra-alveolar pressure falls below atmospheric pressure.
B) The diaphragm contracts.
C) The internal intercostal muscles contract.
D) Intra-alveolar pressure falls below atmospheric pressure and the diaphragm contracts.
E) All of these.

Question 7

Which of the following is the last step that produces an inspiration?

A) The atmospheric pressure becomes lower than the intrapleural pressure.
B) The diaphragm contracts.
C) The intercostal muscles contract.
D) The intra-alveolar pressure becomes lower than the atmospheric pressure.
E) The intrapleural pressure becomes positive.

Question 8

Which of the following is not a function of the respiratory system?

A) transports O₂ to the tissues
B) contributes to maintenance of normal acid-base balance
C) provides a route for heat and water elimination
D) enables speech, singing, and other vocalization
E) removes, modifies, activates, or inactivates various materials passing through the pulmonary circulation

Question 9

When intra-alveolar pressure becomes greater than atmospheric pressure

A) Air will flow out of the lungs.
B) Air will flow into the lungs.
C) There will be no air flow.
D) Air will flow out of the lungs or there will be no air flow.
E) None of these.

Question 10

Airway resistance

A) is normally the primary factor determining the amount of flow into/out of the lungs
B) is increased when the diameter of the airways becomes reduced
C) when elevated, requires an increased pressure gradient between the lungs and atmosphere through vigorous respiratory efforts to move even normal volumes of air into and out of the lungs
D) is increased when the diameter of the airways becomes reduced and, when elevated, requires an increased pressure gradient between the lungs and atmosphere through vigorous respiratory efforts to move even normal volumes of air into and out of the lungs.
E) all of these

Question 11

The entire sequence of events involved in the exchange of O₂ and CO₂ between the body cells and the environment is known as

A) internal respiration
B) external respiration
C) ventilation
D) breathing
E) ventilation and breathing

Question 12

Type I alveolar cells

A) form the wall of the alveoli
B) secrete pulmonary surfactant
C) contract during expiration to force air out of the alveoli
D) form the wall of the alveoli and secrete pulmonary surfactant
E) all of these

Question 13

The respiratory quotient is

A) the rate at which gases diffuse across the alveolar capillary membrane
B) respiratory rate times tidal volume
C) the ratio of O₂ consumed to CO₂ produced
D) the ratio of CO₂ produced to O₂ consumed
E) equal to 1.0 on a typical American diet

Question 14

The intrapulmonary pressure

A) is the pressure within the air sacs of the lung
B) always equilibrates with atmospheric pressure
C) is always less than intrapleural pressure
D) is the pressure within the air sacs of the lung, and always equilibrates with atmospheric pressure
E) all of these

Question 15

During which of the following would the intrapleural pressure be greater than atmospheric pressure?

A) forced inspiration
B) passive expiration
C) passive inspiration
D) pneumothorax
E) none of these

Question 16

When the diaphragm contracts

A) The volume of the thoracic cavity increases.
B) Lung volume increases as the lungs are forced to expand.
C) The intra-alveolar pressure increases.
D) The volume of the thoracic cavity increases and lung volume increases as the lungs are forced to expand.
E) All of these.

Question 17

The inspiratory muscles include the

A) diaphragm and internal intercostal muscles
B) diaphragm and external intercostal muscles
C) diaphragm and abdominal muscles
D) internal and external intercostal muscles
E) none of these

Question 18

Which of the following structures serves as a common passageway for both the respiratory and digestive systems?

A) nose
B) pharynx
C) trachea
D) bronchi
E) esophagus

Question 19

Which statement is incorrect?

A) Alveoli are the site of gas exchange in the lungs.
B) Interdependence of alveoli refers to air flow between adjacent alveoli through the pores of Kohn.
C) Alveolar Type II cells secrete pulmonary surfactant.
D) Alveoli are very thin and are surrounded by a network of capillaries so that air and blood are separated by a very thin barrier.
E) The alveoli are thin-walled, inflatable, grape-like sacs at the end of the bronchioles.

Question 20

At the end of a normal expiration, when outward air flow has ceased,

A) Intra-alveolar pressure is less than atmospheric pressure.
B) Intra-alveolar pressure is greater than atmospheric pressure.
C) Intra-alveolar pressure is equal to atmospheric pressure.
D) Intrapleural pressure is greater than atmospheric pressure.
E) Intrapleural pressure is greater than intra-alveolar pressure.

Question 21

Which of the following promotes elastic recoil of the lungs?

A) elastic fibers in the lung
B) surface tension of the fluid lining the alveoli
C) pulmonary surfactant
D) elastic fibers in the lung and surface tension of the fluid lining the alveoli
E) all of these

Question 22

During forceful expirations

A) The accessory expiratory muscles contract.
B) The internal intercostals contract.
C) The abdominal muscles contract.
D) The ribs are brought closer together.
E) All of these.

Question 23

Without pulmonary surfactant

A) Small alveoli would tend to collapse.
B) Larger alveoli would tend to empty into smaller alveoli.
C) All alveoli would be easier to inflate.
D) The surface tension in the alveoli would be reduced.
E) Inspirations would be easier.

Question 24

Pulmonary surfactant

A) is secreted by Type II alveolar cells
B) decreases surface tension of the fluid lining the alveoli
C) resists elastic recoil of the lungs
D) is a combination of lipids and proteins
E) all of these

Question 25

Bronchodilation of the air passages involves the ____ of their smooth muscle contraction and the ____ of their radius.

A) decrease; decrease
B) decrease; increase
C) increase; decrease
D) increase; increase
E) none of these

Question 26

Which of the following does not occur during expiration when a person is breathing quietly?

A) The size of the thoracic cavity is reduced.
B) The intra-alveolar pressure becomes greater than atmospheric pressure.
C) Air flows out of the lungs.
D) The expiratory muscles contract.
E) Intrapleural pressure is less than intra-alveolar pressure.

Question 27

Normal expirations are brought on by

A) contraction of the external intercostals
B) contraction of the internal intercostals
C) contraction of the diaphragm
D) elastic recoil of inspiratory muscles
E) elastic recoil of expiratory muscles

Question 28

Which skeletal muscle is innervated by the phrenic nerve?

A) rectus abdominus
B) diaphragm
C) external intercostal
D) internal intercostal
E) sternocleodomastoid

Question 29

Which of the following spirometry results would not be expected for a patient suffering from obstructive lung disease?

A) normal total lung capacity
B) increased functional residual capacity
C) decreased residual volume
D) decreased FEV1
E) none of these

Question 30

Which type of chronic obstructive pulmonary disease is characterized by a breakdown of alveolar walls and collapse of the smaller airways?

A) asthma
B) chronic bronchitis
C) emphysema
D) Both chronic bronchitis and emphysema
E) all of these

Question 31

The residual volume

A) helps prevent lung collapse
B) is the normal volume of air inhaled
C) is the normal volume of air exhaled
D) is the maximum volume of air that can be inspired
E) is the minimum volume of air that can be inspired

Question 32

When the level of blood flow is not ideally matched with the amount of airflow in a localized area of lung tissue:

A) Autoregulatory mechanisms are invoked.
B) The autonomic nervous system couples the events more ideally.
C) And if airflow is low and blood flow too high, arteriolar vasoconstriction occurs.
D) Autoregulatory mechanisms are invoked and the autonomic nervous system couples the events more ideally.
E) Autoregulatory mechanisms are invoked and, if airflow is low and blood flow too high, arteriolar vasoconstriction occurs.

Question 33

The vital capacity

A) is the volume normally entering or leaving the lungs during a single breath
B) is the maximum volume that can be moved in or out during a single breath
C) is the maximum volume the lungs can hold
D) is the minimum volume the lungs can hold
E) none of these

Question 34

When blood flow to an area of the lungs is reduced but the area receives normal airflow, all of the following occur except

A) The concentration of CO₂ in this area will be decreased.
B) The change in CO₂ concentration will cause the smooth muscles of the local airways to relax.
C) The change in CO₂ concentration will lead to increased resistance of local airways.
D) The change in O₂ concentration will lead to dilation of local blood vessels.
E) The change in O₂ concentration will lead to decreased vascular resistance.

Question 35

The work of breathing normally requires about 3% of total energy expenditure; this increases under all of the following situations except when:

A) Elastic recoil is decreased.
B) Resistance goes up.
C) The partial pressure of oxygen increases in the air.
D) Ventilation must be increased.
E) Compliance is decreased.

Question 36

Which of the following makes breathing more difficult?

A) increased pulmonary compliance
B) increased airway resistance
C) decreased elastic recoil
D) increased pulmonary compliance and increased airway resistance
E) increased airway resistance and decreased elastic recoil

Question 37

The minimum volume of air that remains in the lungs after a maximal expiration is termed the

A) tidal volume
B) functional residual capacity
C) residual volume
D) vital capacity
E) none of these, since no air remains in the lungs after maximal expiration

Question 38

Which of the following statements concerning pulmonary surfactant is incorrect?

A) It is secreted by Type II alveolar cells.
B) It is deficient in newborn respiratory distress syndrome.
C) It promotes elastic recoil of the lungs.
D) It reduces the cohesive force between water molecules.
E) It reduces surface tension.

Question 39

Which factor would result in bronchoconstriction?

A) sympathetic stimulation
B) parasympathetic stimulation
C) epinephrine secretion
D) increased carbon dioxide concentration
E) none of these

Question 40

Which of the following does not bring about increased airway resistance?

A) asthma
B) epinephrine
C) slow-reactive substance of anaphylaxis
D) emphysema
E) excess mucus production

Question 41

The percent of hemoglobin saturation

A) decreases as $\mathrm { P } _ { 0 _ { 2 } }$ increases
B) decreases as $\mathrm { P } _ { \mathrm { Co } _ { 2 } }$ increases
C) decreases as H⁺ decreases
D) decreases as body temperature decreases
E) none of these

Question 42

Which of the following would decrease diffusion of a gas across the alveolar/pulmonary capillary membrane?

A) an increase in thickness of the membrane
B) an increase in surface area of the membrane
C) an increase in the partial pressure gradient
D) an increase in thickness of the membrane and an increase in the partial pressure gradient
E) all of these

Question 43

The partial pressure of oxygen in the

A) atmospheric air averages 79 percent of total atmospheric pressure
B) blood is the most important factor that determines the extent to which O₂ will combine with hemoglobin
C) arterial blood is decreased when hemoglobin preferentially combines with CO rather than O₂
D) atmospheric air averages 79 percent of total atmospheric pressure, and blood is the most important factor that determines the extent to which O₂ will combine with hemoglobin
E) all of these

Question 44

If 20% of the air is composed of O₂, the partial pressure of oxygen at sea level where atmospheric pressure is 760 mm Hg is

A) 20 mm Hg
B) 760 mm Hg
C) 70 mm Hg
D) 350 mm Hg
E) 152 mm Hg

Question 45

Approximately what percentage of oxygen is transported in the blood dissolved in free form?

A) 1.5
B) 15
C) 60
D) 72
E) 100

Question 46

Which factor would reduce the amount of oxygen transfer across the respiratory membrane?

A) a higher partial pressure of oxygen in the atmosphere
B) an abnormally high partial pressure of carbon dioxide in the atmosphere
C) a reduced partial pressure of carbon dioxide in the atmosphere
D) a low pulmonary capillary, partial pressure of oxygen
E) none of these

Question 47

If the alveolar $\mathrm { P } _ { 0 _ { 2 } }$ is 100 mm Hg, the blood leaving the pulmonary capillaries in a normal person will have a $\mathrm { P } _ { 0 _ { 2 } }$ of

A) 40 mm Hg
B) 46 mm Hg
C) 100 mm Hg
D) 760 mm Hg
E) none of these

Question 48

Compliance refers specifically to the

A) effort required to stretch the lungs
B) elasticity of the lung tissue
C) energy requirements for an inspiration
D) surface area of the alveoli
E) volume of air moved per breathing cycle

Question 49

If 20% of the air is composed of O₂, the partial pressure of oxygen at an altitude of 20,000 feet where atmospheric pressure is 350 mm Hg is

A) 20 mm Hg
B) 760 mm Hg
C) 70 mm Hg
D) 350 mm Hg
E) 152 mm Hg

Question 50

If the pulmonary ventilation rate is 3200 ml/minute with a tidal volume of 400, the respiratory rate is ____ breaths per minute.

A) 6
B) 8
C) 14
D) 16
E) 20

Question 51

A person who has a tidal volume of 400 ml, a respiratory rate of 14, and an anatomic dead space volume of 150 ml will have an alveolar ventilation rate of

A) 3,500 ml/minute
B) 3,920 ml/minute
C) 4,260 ml/minute
D) 5,600 ml/minute
E) 6,240 ml/minute

Question 52

Hemoglobin has the greatest affinity for

A) carbon dioxide
B) oxygen
C) carbon monoxide
D) nitrogen
E) sulfur dioxide

Question 53

Which condition would result in the lowest alveolar ventilation rate?

A) quiet breathing
B) a normal respiratory rate and normal tidal volume
C) a low respiratory rate and high tidal volume
D) a high respiratory rate and very low tidal volume
E) a low respiratory rate and very low tidal volume

Question 54

$\mathrm { P } _ { 0 _ { 2 } }$ in the blood

A) refers to the pressure exerted by the amount of oxygen dissolved in the blood
B) is the most important factor determining the percent saturation of hemoglobin
C) is normal in carbon monoxide poisoning
D) refers to the pressure exerted by the amount of oxygen dissolved in the blood and is normal in carbon monoxide poisoning
E) all of these

Question 55

The partial pressure of oxygen in the pulmonary veins is

A) about 40 mmHg
B) equivalent to alveolar partial pressure
C) dramatically different than pulmonary arteries' partial pressure
D) about 40 mmHg and equivalent to alveolar partial pressure
E) all of these

Question 56

A person who has a tidal volume of 400 ml/breath, a respiratory rate of 14 breaths/minute, and an anatomic dead space volume of 120 ml will have a pulmonary ventilation rate of

A) 3000 ml/minute
B) 3920 ml/minute
C) 4260 ml/minute
D) 5600 ml/minute
E) 6240 ml/minute

Question 57

Systemic venous $\mathrm { P } _ { 0 _ { 2 } }$ is ____ alveolar $\mathrm { P } _ { 0 _ { 2 } }$ , and systemic venous $\mathrm { P } _ { 0 _ { 2 } }$ is ____ alveolar $\mathrm { P } _ { 0 _ { 2 } }$ .

A) greater than; greater than
B) greater than; less than
C) less than; greater than
D) less than; less than
E) equal to; equal to

Question 58

Which of the following forces does not contribute to keeping the alveoli open?

A) alveolar surface tension
B) transmural pressure gradient.
C) pulmonary surfactant
D) alveolar interdependence
E) none of these

Question 59

Intrapleural pressure exceeds airway pressure

A) during normal quiet breathing
B) during maximal forced expiration
C) in response to a pneumothorax
D) during maximal forced expiration and in response to a pneumothorax
E) all of these

Question 60

Which factor would reduce the alveolar ventilation rate the most?

A) increased alveolar dead space
B) decreased alveolar dead space
C) increased respiratory rate
D) increased tidal volume
E) quiet breathing

Question 61

Carbon dioxide is transported in the blood in all the following ways except

A) bicarbonate ion
B) carbonic acid
C) directly dissolved
D) bound to heme
E) bound to globin

Question 62

The stretch receptors for the Hering-Breuer reflex are located in the

A) diaphragm
B) elastic tissue of the lungs
C) medulla
D) smooth muscle of the airways
E) trachea

Question 63

The primary regulator of the magnitude of ventilation in normal circumstances is the

A) H⁺ concentration of the brain extracellular fluid monitored by central chemoreceptors
B) $\mathrm { P } _ { 0 _ { 2 } }$ of the arterial blood monitored by central chemoreceptors
C) $\mathrm { P } _ { 0 _ { 2 } }$ of the arterial blood monitored by peripheral chemoreceptors
D) $\mathrm { P } _ { \mathrm { Co } _ { 2 } }$ of arterial blood monitored by central chemoreceptors
E) $\mathrm { P } _ { \mathrm { Co } _ { 2 } }$ of arterial blood monitored by peripheral chemoreceptors

Question 64

The brain region that provides output to the respiratory muscles is located in the

A) pons
B) medulla
C) cerebral cortex
D) cerebellum
E) hypothalamus

Question 65

Carbonic anhydrase

A) is found in the red blood cells
B) catalyzes the formation of carbonic acid from carbonic dioxide and water
C) catalyzes the formation of oxyhemoglobin from oxygen and reduced hemoglobin
D) is found in the red blood cells and catalyzes the formation of carbonic acid from carbonic dioxide and water
E) catalyzes the formation of carbonic acid from carbonic dioxide and water, and catalyzes the formation of oxyhemoglobin from oxygen and reduced hemoglobin

Question 66

Select the incorrect statement about hemoglobin.

A) It combines with oxygen at the lungs.
B) It contains iron.
C) It forms an irreversible association with oxygen.
D) It is located inside the red blood cell.
E) Its globin portion is a polypeptide.

Question 67

Pacemaker activity that establishes the rhythmicity of breathing resides in the

A) lung tissue
B) respiratory muscles
C) dorsal respiratory group
D) phrenic nerve
E) reciprocal relationship between the inspiratory and expiratory neurons of the ventral respiratory group

Question 68

The apneustic center

A) is located in the medulla
B) stimulates the inspiratory neurons
C) inhibits inspiratory activity
D) stimulates the inspiratory neurons and inhibits inspiratory activity
E) none of these

Question 69

2,3-diphosphoglycerate

A) is produced within red blood cells
B) production is inhibited by HbO₂
C) concentration gradually increases whenever Hb in the arterial blood is chronically undersaturated
D) none of these
E) all of these

Question 70

The inspiratory neurons

A) activate the phrenic nerve, bringing about contraction of the diaphragm
B) are stimulated by stretch receptors
C) are inhibited by the expiratory neurons
D) activate the phrenic nerve, bringing about contraction of the diaphragm, and are inhibited by the expiratory neurons
E) none of these

Question 71

The chloride shift in red blood cells

A) prevents electrical gradient development
B) occurs in response to bicarbonate movement into the plasma
C) prevents an increase in blood pH
D) prevents electrical gradient development and occurs in response to bicarbonate movement into the plasma
E) all of these

Question 72

Approximately what percent of carbon dioxide is transported in the blood dissolved in dissolved form?

A) 1.5
B) 10
C) 35
D) 60
E) 100

Question 73

What is the primary form in which CO₂ is transported in the blood?

A) physically dissolved
B) bound to hemoglobin
C) bound to plasma protein
D) as bicarbonate
E) as carbonic anhydrase

Question 74

Which condition exists at high altitudes?

A) histotoxic hypoxia
B) hypoxic hypoxia
C) anemic hypoxia
D) hypocapnia
E) none of these

Question 75

Identify the correct statement(s).

A) The presence of hemoglobin keeps the blood $\mathrm { P } _ { 0 _ { 2 } }$ low and favors O₂ movement into the blood, despite a very large transfer of O₂ until hemoglobin is completely saturated.
B) Hemoglobin can combine with O₂, CO₂, H⁺, and CO.
C) Hemoglobin unloads more O₂ in the presence of increased tissue acidity.
D) Hemoglobin buffers against changes in pH due to respiratory carbonic acid.
E) All of these.

Question 76

Select the factor in the arterial blood that has the largest effect on increasing the rate of respiration.

A) increase in the hydrogen ion concentration in the kidneys
B) increase in the hydrogen ion concentration in the arterial blood
C) any decrease in the partial pressure of carbon dioxide
D) any decrease in oxygen's partial pressure
E) detection of CO₂ by central chemoreceptors

Question 77

Identify the correct statement(s).

A) The DRG consists of both inspiratory neurons and expiratory neurons.
B) The neurons of the DRG remain inactive during normal quiet breathing.
C) The DRG is called into play by the VRG as when demands for ventilation are increased.
D) All of these.
E) None of these.

Question 78

Hypercapnia

A) refers to excess CO₂ in the arterial blood
B) occurs when CO₂ is blown off to the atmosphere at a rate faster than it is being produced by the tissues
C) may be caused by hypoventilation
D) all of these
E) refers to excess CO₂ in the arterial blood and may be caused by hypoventilation

Question 79

Hemoglobin

A) combines preferentially with O₂ over any other substance
B) when combined with carbon dioxide, is known as carboxyhemoglobin
C) plays a critical role in determining the amount of O₂ that is exchanged between alveoli and blood because it acts as a storage depot, removing dissolved O₂ from the blood and keeping $\mathrm { P } _ { 0 _ { 2 } }$ low by allowing net diffusion of O₂ to continue until the hemoglobin is completely saturated
D) combines preferentially with O₂ over any other substance, and when combined with carbon dioxide, is known as carboxyhemoglobin
E) all of these

Question 80

Expiratory neurons

A) are found in both the DRG and VRG
B) send impulses to the expiratory muscles during normal quiet breathing
C) are stimulated by the phrenic nerve
D) are stimulated by the apneustic area
E) none of these