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CHAPTER 46—GAS EXCHANGE: THE RESPIRATORY SYSTEM
MULTIPLE CHOICE
1. Of the following cells, which are most sensitive to reduced O2 levels?
a.
heart cells
b.
kidney cells
c.
liver cells
d.
brain cells
e.
pancreatic cells
2. As elevation increases
a.
O2 availability increases.
b.
O2 availability decreases.
c.
O2 availability remains constant.
d.
O2 levels increase, but there is none present above 20,000 feet.
e.
O2 levels decrease, but there is none present above 20,000 feet.
3. Planes maintain an atmospheric pressure equivalent to about 8,000 feet to
a.
maintain a stable temperature.
b.
maintain oxygen levels.
c.
maintain oxygen availability.
d.
maintain oxygen levels and maintain oxygen availability.
e.
maintain oxygen availability and reduce buildup of carbon dioxide.
4. Which of the following NOT is an example of a respiratory surface?
a.
amphibian skin
b.
human lungs
c.
fish gills
d.
ctenophore body surfaces
e.
fish scales
5. In humans, which of the following is involved in both cellular respiration and physiological
respiration?
a.
the circulatory system
b.
the respiratory surface
c.
mitochondria
d.
the respiratory medium
e.
blood
6. Through what process is O2 transported from air in the lungs into the blood?
a.
active transport
b.
simple diffusion
c.
facilitated diffusion
d.
osmosis
e.
active transport
7. Which of the following respiratory surface properties enhances the diffusion of respiratory gases?
a.
large surface area
b.
thick epithelial layer
c.
cool temperatures
d.
the presence of active transport pumps
e.
presence of carbon dioxide
8. Which of the following respiratory structures are moist evaginations?
a.
tracheal tubes
b.
lungs
c.
gills
d.
skin
e.
nasal passages
9. Which of the following air-filled respiratory system structures are common in insects?
a.
gills
b.
tracheal tubes
c.
lungs
d.
integumentary surfaces
e.
air sacs
10. Which of the following describes the exchange of gases between a respiratory surface and the
circulatory system?
a.
ventilation
b.
cellular respiration
c.
perfusion
d.
bulk flow
e.
physiological respiration
11. Which of the following adaptations would NOT increase the surface area of a respiratory surface?
a.
skin folds on an amphibian
b.
a flatworm having a broad, flat body
c.
branched gill filaments
d.
internal folds within lungs
e.
endothermy
12. Why is proper ventilation important for a respiring animal?
a.
It directly increases gas exchange between the blood and cells.
b.
It maintains proper O2 and CO2 levels on the external side of the respiratory surface so
diffusion across it can be maintained.
c.
It maintains blood circulation within the body of an animal.
d.
It maintains proper O2 and CO2 levels on the internal side of the respiratory surface so
diffusion across it can be maintained.
e.
It maintains proper O2 and CO2 levels in tissues.
13. In which of the following animals would perfusion be LEAST efficient during gas exchange?
a.
a bird
b.
a frog
c.
a fish
d.
a flatworm
e.
a human
14. Which of the following is an advantage of water as a respiratory medium?
a.
Water holds less O2 than air.
b.
In water, O2 concentration can be affected by solute concentration.
c.
The density of water makes it more difficult to ventilate over the respiratory surface.
d.
In water, O2 concentration can be affected by temperature.
e.
Water keeps the respiratory surface wetted.
15. Which is a disadvantage of air as a respiratory medium?
a.
Air evaporates water from the respiratory surface.
b.
Air contains 30 times as much O2 as water.
c.
Air is 1000 times less dense than water.
d.
Air requires less energy to ventilate over the respiratory surface.
e.
O2 diffuses more rapidly in air than in water.
16. Which respiratory surface lacks physical protection from the external environment?
a.
tracheal system tubes
b.
human lungs
c.
external gills
d.
internal gills
e.
bird lungs
17. Why does countercurrent exchange optimize gas exchange across some gills?
a.
It sustains an optimal thermal environment for gas exchange.
b.
It optimizes perfusion to the respiratory surface.
c.
It sustains an optimal respiratory gas concentration gradient, allowing diffusion to occur
across the entire respiratory surface.
d.
It optimizes delivery of the respiratory medium to the respiratory surface.
e.
It minimizes diffusional area.
18. Countercurrent exchange allows for the removal of ____ of O2 from water flowing over gills.
a.
50−60 percent
b.
60−70 percent
c.
70−80 percent
d.
80−90 percent
e.
90−100 percent
19. Which of the following lists the correct order of tracheal system structures, from most external to most
internal?
a.
spiracles, tracheae, tracheal branches, tracheoles
b.
tracheoles, tracheae, tracheal branches, spiracles
c.
tracheoles, tracheal branches, tracheae, spiracles
d.
spiracles, tracheal branches, tracheae, tracheoles
e.
spiracles, tracheoles, tracheae, tracheal branches
20. Where in an insect tracheal system does gas exchange occur between the air and a cell?
a.
trachea
b.
tracheal branches
c.
gill filaments
d.
tracheoles
e.
spiracles
21. Which of the following animals use positive pressure breathing to ventilate its lungs?
a.
a bird
b.
a frog
c.
a dog
d.
a reptile
e.
a human
22. Which of the following animals use air sacs to ventilate its lungs?
a.
humans
b.
birds
c.
frogs
d.
reptiles
e.
horses
23. Among air breathing animals, birds have the most effective mechanism of extracting oxygen from air
because
a.
birds utilize countercurrent exchange.
b.
bird lungs have more surface area.
c.
bird lungs are the largest among vertebrates.
d.
the air sacs provide additional respiratory surfaces.
e.
birds utilize positive force exchange.
24. During which part of the bird respiratory cycle is O2 NOT extracted from the air?
a.
the first inhalation
b.
the first exhalation
c.
the second inhalation
d.
the second exhalation
e.
the third exhalation
25. The respiratory surfaces of mammalian lungs are called
a.
alveoli.
b.
bronchi.
c.
tracheae.
d.
bronchioles.
e.
air sacs.
26. The ____ is/are responsible for closing off the airway during swallowing.
a.
larynx
b.
epiglottis
c.
pharynx
d.
intercostal muscles
e.
pleura
27. The ____ are the initial branches of the trachea that lead into each lung.
a.
bronchioles
b.
alveoli
c.
pleura
d.
bronchi
e.
larynx
28. Which of the following occurs during human inhalation?
a.
The diaphragm contracts and the external intercostal muscles relax.
b.
The diaphragm relaxes and the external intercostal muscles contract.
c.
The diaphragm contracts and the external intercostal muscles contract.
d.
The diaphragm relaxes and the external intercostal muscles relax.
e.
The diaphragm expands and increases oxygen uptake.
29. During exhalation, the chest cavity ____ in size, which causes air pressure in the lungs to ____.
a.
increases; increase
b.
decreases; decrease
c.
increases; decrease
d.
decreases; increase
e.
expands, cause pressure
30. During resting breathing in humans, which of the following is accurate?
a.
The diaphragm contracts and the internal intercostal muscles relax.
b.
The diaphragm relaxes and the internal intercostal muscles contract.
c.
The diaphragm contracts and the internal intercostal muscles contract.
d.
The diaphragm relaxes and the external intercostal muscles contract.
e.
Rib muscles and the diaphragm relax.
31. The primary muscle(s) involved in human breathing is/are called the
a.
external intercostals.
b.
internal intercostals.
c.
diaphragm.
d.
abdominal wall muscles.
e.
lung muscles.
32. Which of the following muscles contract during forceful exhalation?
a.
the diaphragm
b.
external intercostals
c.
internal intercostals
d.
the diaphragm and external intercostals
e.
the diaphragm and internal intercostals
33. Airways of the mammalian respiratory system function to
a.
filter oxygen from carbon dioxide.
b.
moisten external air.
c.
cool external air.
d.
filter water out of the air.
e.
keep water out of the lungs.
34. Which of the following mammalian airway structures acts as the "windpipe"?
a.
the bronchus
b.
the trachea
c.
the larynx
d.
the bronchiole
e.
the pharynx
35. Air movement to the mammalian respiratory surfaces can be reduced when smooth muscle in the walls
of the ____ contract(s).
a.
epiglottis
b.
bronchioles
c.
large bronchi
d.
trachea
e.
aorta
36. Which of the following lung volumes keep the lungs from completely deflating, even after a maximal
exhalation?
a.
residual volume
b.
tidal volume
c.
vital capacity
d.
lung capacity
e.
lung volume
37. Which of the following lung volumes change during exercise?
a.
residual volume
b.
tidal volume
c.
vital capacity
d.
lung capacity
e.
lung volume
38. Which of the following chemicals has the LEAST influence on the regulation of breathing rate?
a.
O2.
b.
CO2.
c.
H+.
d.
N2.
e.
CO.
39. Which respiratory control center sets basic breathing rate by acting as the primary stimulator of
inhalation?
a.
the ventral interneuron group
b.
the pons interneuron groups
c.
the carotid bodies
d.
the dorsal respiratory group
e.
the aortic bodies
40. Which respiratory control center is responsible for forceful inhalation and exhalation?
a.
the ventral interneuron group
b.
the pons interneuron groups
c.
the carotid bodies
d.
the dorsal respiratory group
e.
the aortic bodies
41. Which respiratory control center is most sensitive to changes in CO2?
a.
aortic bodies
b.
carotid bodies
c.
receptors of the medulla
d.
receptors of the aorta
e.
medulla bodies
42. Which of the following respiratory control centers allows you to hold your breath before diving into a
swimming pool?
a.
aortic bodies
b.
carotid bodies
c.
receptors of the medulla
d.
the limbic center of the brain
e.
higher brain centers of the cerebrum
43. Which of the following is an example of local control over breathing?
a.
automated lung ventilation and lung perfusion adjustments maximizing O2 and CO2
exchange
b.
the aortic bodies signaling an increase in breathing rate when blood pH is acidic
c.
the interneuron groups of the pons refining the contractions involved with inhalation and
exhalation
d.
the carotid bodies signaling an increase in breathing rate when O2 levels are low
e.
the ventral group of interneurons signaling an increase in breathing rate and depth during
exercise
44. If N2 gas comprises 79 percent of atmospheric air at sea level, what is PN2?
a.
about 300 mm Hg
b.
about 400 mm Hg
c.
about 500 mm Hg
d.
about 600 mm Hg
e.
about 700 mm Hg
45. What would you predict would happen in an area of the body where blood was relatively cool?
a.
O2 would bind more readily to hemoglobin.
b.
CO2 would bind more readily to hemoglobin.
c.
O2 would release from hemoglobin.
d.
CO2 would release from hemoglobin.
e.
binding of O2 by hemoglobin would cease.
46. What would you predict would happen in an area of the body where blood was relatively acidic (low
pH)?
a.
O2 would bind more readily to hemoglobin.
b.
CO2 would bind more readily to hemoglobin.
c.
O2 would release from hemoglobin.
d.
CO2 would release from hemoglobin.
e.
binding of O2 by hemoglobin would cease.
47. Most O2 is transported in the blood
a.
dissolved in the plasma.
b.
as bicarbonate ions.
c.
bound to hemoglobin.
d.
as carbon dioxide.
e.
bound to bicarbonate ions.
48. CO2 is transported in the blood in which of the following?
a.
dissolved in the plasma exclusively.
b.
as bicarbonate ions exclusively.
c.
bound to hemoglobin exclusively.
d.
dissolved in the red blood cells exclusively.
e.
dissolved in the plasma, as bicarbonate ions and bound to hemoglobin.
49. The function of carbonic anhydrase is
a.
to speed up the conversion of CO2 and H2O into HCO3− and H+.
b.
to speed up the conversion of HCO3− and H+ into CO2 and H2O.
c.
to speed up the rate at which CO2 binds to hemoglobin.
d.
to speed up the conversion of CO2 and H2O into HCO3− and H+, and to speed up the
conversion of HCO3− and H+ into CO2 and H2O.
e.
to speed up the conversion of HCO3− and H+ into CO2 and H2O, and to speed up the rate at
which CO2 binds to hemoglobin.
50. Which of the following events occurs in lung blood?
a.
Free H+ binds to hemoglobin.
b.
Plasma HCO3− enters erythrocytes.
c.
In the plasma, CO2 and H2O are converted into HCO3− and H+.
d.
In erythrocytes, carbonic anhydrase converts CO2 and H2O into HCO3− and H+.
e.
CO2 binds to hemoglobin.
51. Which of the following events occurs in blood in body tissue?
a.
free H+ releases from hemoglobin.
b.
erythrocyte HCO3− enters the plasma.
c.
in the plasma, HCO3− and H+ convert into CO2 and H2O.
d.
in erythrocytes, carbonic anhydrase converts HCO3− and H+ into CO2 and H2O.
e.
CO2 binds to hemoglobin.
52. Which has the greatest affinity for carbon monoxide?
a.
The heme group in hemoglobin associated with the polypeptide chain of hemoglobin.
b.
The heme group in hemoglobin unassociated with the polypeptide chain of hemoglobin.
c.
The heme group in myoglobin associated with the polypepetide chain of myoglobin.
d.
The affinity is the same for heme groups in hemoglobin or myoglobin associated or
unassociated with the polypeptide chains of hemoglobin or myoglobin.
e.
The heme group of mutated myoglobin.
53. To test the hydrogen-bond hypothesis for reduced affinity of the heme group for carbon monoxide
when the heme is associated with polypeptide chains, the researchers used which of the following
model systems?
a.
Mutated rat myoglobin.
b.
Mutated rat hemoglobin.
c.
Myglobin gene isolated from a bacteria and introduced into sperm whale.
d.
Myglobin gene isolated from a sperm whale and introduced into a bacteria.
e.
Hemoglobin gene isolated from a sperm whale and introduced into a bacteria.
54. What is the purpose of using bacteria to study the function of myoglobin?
a.
Bacterial myoglobin is similar to mammal myoglobin.
b.
Bacteria genes are easier to clone than mammal genes.
c.
Bacteria can express a myoglobin gene and myoglobin molecules can be produced in
quantity.
d.
Bacterial reproduction rates.
e.
Rates of evolutionary change in bacteria.
55. Which of the following are examples of adaptations that do not result from living at high altitudes?
a.
elevated erythrocyte count
b.
increased number of alveoli
c.
increased number of lung capillaries
d.
hemoglobin molecules with greater affinity for O2
e.
decreased erythrocyte count
56. As altitude increases
a.
PO2 increases
b.
PO2 decreases
c.
PCO2 increases
d.
PCO2 decreases
e.
PN2 increases
57. Traveling to a high altitude can result in “altitude sickness.” However, the body eventually adjusts
through which mechanism?
a.
Increased hemoglobin production.
b.
Increased erythrocyte production.
c.
Increased secretion of erythropoietin.
d.
Increased hemoglobin production and increased erythrocyte production.
e.
Increased hemoglobin production as a result of increased secretion of erythropoietin.
58. During a dive, the partial pressure of dissolved gases increases by about 1 atm for every ____ in depth.
a.
1 meter
b.
5 meters
c.
10 meters
d.
15 meters
e.
20 meters
59. Some deer mice are physiologically adapted to live at high altitudes because of the following:
a.
adults maintain fetal forms of hemoglobin.
b.
mutations in hemoglobin that increase its oxygen-binding affinity.
c.
mutations in myoglobin that increase its oxygen-binding affinity.
d.
mutations that increase heart rates.
e.
mutations that decrease heart rates.
60. The number-one risk factor for sudden infant death syndrome (SIDS) is
a.
an infant lying on their back.
b.
breast feeding an infant.
c.
premature feeding of solid foods.
d.
exposure to tobacco smoke.
e.
holding the infant.
61. Studies indicate that in utero nicotine exposure can cause breathing abnormalities in neonatal
mammals. These abnormalities can include
a.
elevated breathing rate while awake.
b.
increased frequency of apneas during sleep.
c.
delayed arousal from sleep in response to hypoxia.
d.
elevated breathing rate while awake and increased frequency of apneas during sleep.
e.
increased frequency of apneas during sleep and delayed arousal from sleep in response to
hypoxia.
62. Respiratory neurons from the dissected brainstem of a neonatal rodent can maintain rhythmic firing for
how many hours?
a.
0
b.
1
c.
4
d.
6
e.
8
63. What breathing abnormalities can occur in neonatal mammals exposed to nicotine?
a.
reduced ventilator output.
b.
increased duration of apneas.
c.
SIDS.
d.
reduced ventilator output and increased duration of apneas.
e.
reduced ventilator output, increased duration of apneas and SIDS.
64. Which of the following mechanisms is NOT used to encourage the movement of water over gills?
a.
cilia
b.
contraction of the diaphragm
c.
contraction of a muscular mantle
d.
a fish swimming with its mouth open
e.
contractions of body muscles
65. Which of the following animals does NOT use negative pressure breathing to ventilate its lungs?
a.
a human
b.
a lizard
c.
a bird
d.
a cat
e.
a salamander
66. Which of the following is NOT an adaptation used by marine mammals to extend dive times?
a.
size-relative increase in blood volume.
b.
increase in erythrocyte count
c.
size-relative increase in lung volume
d.
elevated concentration of muscle myoglobin
e.
reduced circulation to nonessential organs
67. Which organ or organs are used by marine mammals during deep dives?
a.
the lungs
b.
the heart
c.
the brain
d.
the blood vessels
e.
the heart, the brain, and blood vessels
MATCHING
Match each of the following terms with its correct description.
a.
The flow of blood (or body fluids) on the internal side of the respiratory surface
b.
Gas exchange between the blood and body tissue cells
c.
The general term used to describe an animal's exchange of gases with the respiratory
medium
d.
Specifically describes the release of air from the lungs to the atmosphere
e.
The flow of the respiratory medium over the external side of the respiratory surface
f.
Occurs due to the expansion of the lungs and thoracic cavity
g.
The exchange of gases between the respiratory medium and the blood (or internal body
fluids)
68. breathing
69. ventilation
70. perfusion
71. physiological respiration
72. cellular respiration
73. inhalation
74. exhalation
MODIFIED TRUE/FALSE
If the statement is true, answer "T". If the statement is false, answer "F" and make it correct by
changing the underlined word(s) and writing the correct word(s) in the answer blank(s).
75. The circulatory surface provides the interface between the body and the respiratory medium.
76. Birds utilize countercurrent mechanisms to optimize diffusion of O2 across their respiratory surfaces.
77. A larynx is found at the beginning of each insect trachea.
78. Humans ventilate their lungs by negative pressure breathing.
79. When the diaphragm contracts, it moves up into the thoracic cavity, thereby decreasing its volume.
80. Each molecule of hemoglobin can bind to six molecules of oxygen.
81. Blood O2 levels have the greatest influence on mammalian breathing rate.
82. CO2 and H2O are converted to HCO3− and H+ in the blood of the lungs.
83. Alveoli are the respiratory surfaces of birds.
930
84. Alveoli are surrounded by pulmonary capillaries.
COMPLETION
Labeling
85. For the following question(s), consult the diagram of the human respiratory system below. Write your
answers in the spaces provided.
Identify structure A:
Identify structure B:
Identify structure C:
Identify structure D:
Identify structure E:
Identify structure F:
Identify structure G:
Identify structure H:
Identify structure I:
Identify structure J:
Identify structure K:
Identify structure L:
SHORT ANSWER
86. Describe three adaptations that enhance the function of a respiratory surface.
87. Compare the efficiency of mammal lungs and fish gills.
88. Compare control of breathing in a human before and during physical exercise.
89. Llamas, which are customarily known as mountain dwellers, have hemoglobin with higher O2 binding
affinity than that of humans. That being said, how would you predict the llama hemoglobin-O2
dissociation curve would differ compared to that of a human (see diagram below)?
OBJ: Bloom's Taxonomy: Knowledge | Bloom's Taxonomy: Application
90. Explain how a diving marine mammal increases its supply of stored O2, in spite of the fact that its
lungs are collapsed at depths below 25 meters.
