Deck 46: Gas Exchange: the Respiratory System

Question 1

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

Answer 1

C

Question 2

Why is proper ventilation important for a respiring animal?

A) It directly increases gas exchange between the blood and cells.
B) It maintains proper O₂and CO₂levels 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 O₂and CO₂levels on the internal side of the respiratory surface so diffusion across it can be maintained.
E) It directly maintains proper O₂and CO₂levels in tissues.

Answer 2

B

Question 3

As elevation increases, O₂____.

A) availability increases
B) availability decreases
C) availability remains constant
D) levels increase, but there is none present above 20,000 feet
E) levels decrease, until there is none present above 20,000 feet

Answer 3

B

Question 4

In aquatic animals, the most disadvantaged in terms of respiratory media are those living in ____.

A) cold saltwater
B) cold freshwater
C) warm saltwater
D) warm freshwater
E) warm brackish water

Question 5

Amphibians often use ____ as a respiratory surface.

A) skin
B) a tracheal system
C) internal gills
D) external gills
E) scales

Question 6

Choose 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

Question 7

O₂is transported from air in the lungs into the blood through the process of ____.

A) active transport
B) simple diffusion
C) facilitated diffusion
D) osmosis
E) active transport

Question 8

The ____ cells are most sensitive to reduced O₂levels.

A) heart
B) kidney
C) liver
D) brain
E) pancreatic

Question 9

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 the area of diffusion.

Question 10

Water is an optimal respiratory medium because ____.

A) water holds less O₂than air
B) O₂concentration in water is affected by solute concentration
C) the density of water allows maximal ventilation over the respiratory surface
D) O₂concentration in water increases at higher temperatures
E) water keeps the respiratory surface wetted

Question 11

In humans, ____ is involved in both cellular and physiological respiration.

A) the circulatory system
B) the respiratory surface
C) mitochondria
D) the respiratory medium
E) blood

Question 12

Gas exchange between the air and a cell in an insect tracheal system occurs at the ____.

A) trachea
B) tracheal branches
C) gill filaments
D) tracheoles
E) spiracles

Question 13

The ____ are respiratory structures composed of moist evaginations.

A) tracheal tubes
B) lungs
C) gills
D) skin cells
E) nasal passages

Question 14

Diffusion of respiratory gases is enhanced by ____.

A) a large surface area
B) a thick epithelial layer
C) cool temperatures
D) the presence of active transport pumps
E) the presence of carbon dioxide

Question 15

The process of ____ is 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

Question 16

Countercurrent exchange allows for the removal of ____ percent of O₂from water flowing over gills.

A) 50 - 60
B) 60 - 70
C) 70 - 80
D) 80 - 90
E) 90 - 100

Question 17

Planes maintain an atmospheric pressure equivalent to about 8,000 feet to sustain ____.

A) a stable temperature
B) oxygen levels
C) oxygen availability
D) oxygen levels and availability
E) oxygen availability and reduce buildup of carbon dioxide

Question 18

The ____ are air-filled respiratory system structures common in insects.

A) gills
B) tracheal tubes
C) lungs
D) integumentary surfaces
E) air sacs

Question 19

The ____ represent an internal respiratory system.

A) skin folds on an amphibian
B) broad, flat body of a flatworm
C) branched gill filaments
D) folds within human lungs
E) gills on a salamander

Question 20

Air is the least optimal respiratory medium because ____.

A) air flow increases evaporation of water from the respiratory surface
B) air contains 30 times as much O₂as water
C) air is 1,000 times less dense than water
D) air requires more energy to ventilate over the respiratory surface
E) O₂diffuses more rapidly in air than in water

Question 21

Air becomes deoxygenated during the ____ of a bird's respiratory cycle.

A) first inhalation
B) first exhalation
C) second inhalation
D) second exhalation
E) third exhalation

Question 22

The ____ is/are responsible for closing off the airway during swallowing.

A) larynx
B) epiglottis
C) pharynx
D) intercostal muscles
E) pleura

Question 23

A ____ uses air sacs to ventilate its lungs.

A) human
B) bird
C) frog
D) reptile
E) horse

Question 24

The respiratory surfaces of mammalian lungs are called ____.

A) alveoli
B) bronchi
C) tracheae
D) bronchioles
E) air sacs

Question 25

The primary muscle(s) involved in human breathing is/are the ____.

A) external intercostals
B) internal intercostals
C) diaphragm
D) abdominal wall
E) lung

Question 26

The ____ stimulate(s) forceful inhalation and exhalation.

A) ventral respiratory group
B) pons respiratory group
C) carotid bodies
D) dorsal respiratory group
E) aortic bodies

Question 27

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

Question 28

The concentration of ____ has the greatest influence on the regulation of breathing rate.

A) O₂
B) CO₂
C) H⁺
D) N₂
E) CO

Question 29

Among air breathing animals, birds have the most effective mechanism of extracting oxygen from air because ____.

A) birds utilize crosscurrent 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

Question 30

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; remain the same

Question 31

The ____ keeps 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

Question 32

The ____ drive(s) inhalation by stimulating contraction of the diaphragm and intercostal muscles.

A) ventral respiratory group
B) pons respiratory group
C) carotid bodies
D) dorsal respiratory group
E) aortic bodies

Question 33

During human inhalation, the diaphragm ____ and the external intercostal muscles ____.

A) contracts; relax
B) relaxes; contract
C) contracts; contract
D) relaxes; relax
E) expands; vibrate

Question 34

A ____ uses positive pressure breathing to ventilate its lungs.

A) bird
B) frog
C) dog
D) reptile
E) human

Question 35

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

Question 36

During resting exhalation in humans, the diaphragm ____ and the internal intercostal muscles ____.

A) contracts; relax
B) relaxes; contract
C) contracts; contract
D) relaxes then contracts; contract then relax
E) relaxes; relax

Question 37

During forceful exhalation, the ____ muscles contract.

A) diaphragm and abdominal
B) external intercostal
C) internal intercostal
D) diaphragm and external intercostal
E) diaphragm and internal intercostal

Question 38

The ____ in the mammalian airway acts as the "windpipe."

A) bronchus
B) trachea
C) larynx
D) bronchiole
E) pharynx

Question 39

The ____ are the initial branches of the trachea that lead into each lung.

A) bronchioles
B) alveoli
C) pleura
D) bronchi
E) larynx

Question 40

The ____ changes during exercise.

A) residual volume
B) tidal volume
C) vital capacity
D) lung capacity
E) lung volume

Question 41

Decreases in CO₂concentration result in ____.

A) faster breathing
B) deeper breathing
C) faster and deeper breathing
D) slower and more shallow breathing
E) slower breathing

Question 42

CO₂is transported in the blood ____.

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

Question 43

Living at high altitudes can cause ____ as a respiratory adaptation.

A) elevated erythrocyte count
B) decreased number of alveoli
C) decreased number of lung capillaries
D) hemoglobin molecules with less affinity for O₂
E) decreased erythrocyte count

Question 44

Which event occurs in the lungs?

A) Free H⁺binds to hemoglobin.
B) Plasma HCO₃- enters erythrocytes.
C) CO₂and H₂O are converted into HCO₃- and H⁺in the plasma.
D) Carbonic anhydrase converts CO₂and H₂O into HCO₃- and H⁺in erythrocytes.
E) CO₂binds to hemoglobin.

Question 45

The ____ are 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

Question 46

What would you predict would happen in an area of the body where blood was relatively acidic (low pH)?

A) O₂would bind more readily to hemoglobin.
B) CO₂would bind more readily to hemoglobin.
C) O₂would release from hemoglobin.
D) CO₂would release from hemoglobin.
E) Binding of O₂by hemoglobin would cease.

Question 47

An example of local control over breathing is ____.

A) automated lung ventilation and perfusion adjustments to changing O₂levels in the blood
B) the aortic bodies signaling an increase in breathing rate when blood pH is acidic
C) refinement by the pons respiratory group of contractions involved in inhalation and exhalation
D) the carotid bodies signaling an increase in breathing rate when O₂levels are low
E) the ventral respiratory group signaling an increase in breathing rate and depth during exercise

Question 48

Traveling to a high altitude can result in "altitude sickness"; however, the body eventually adjusts through ____.

A) increased hemoglobin circulation
B) decreased erythrocyte production
C) increased secretion of erythropoietin
D) decreased hemoglobin circulation
E) decreased secretion of erythropoietin

Question 49

If N₂gas comprises 79 percent of atmospheric air at sea level, what is P_N2?

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

Question 50

Victims of CO poisoning turn "classic cherry red" in ____ percent of cases.

A) 90
B) 50
C) 20
D) 2
E) 0

Question 51

As altitude increases, ____.

A) P_O2increases
B) P_O2decreases
C) P_CO2increases
D) P_CO2decreases
E) P_N2increases

Question 52

During a dive, a marine mammal experiences an increase in the partial pressure of dissolved gases of about 1 atmosphere for every ____ meter(s) in depth.

A) 1
B) 5
C) 10
D) 15
E) 20

Question 53

As oxygenated blood enters tissue capillaries, the oxygen ____.

A) binds more tightly to hemoglobin
B) diffuses from blood plasma into body cells
C) diffuses from interstitial fluid into blood plasma
D) acts as a substrate for carbonic anhydrase
E) reaches equilibrium in blood plasma and interstitial fluid

Question 54

What would you predict would happen in an area of the body where P_O2is relatively low?

A) O₂would bind more readily to hemoglobin.
B) CO₂would bind more readily to hemoglobin.
C) O₂would release from hemoglobin.
D) CO₂would release from hemoglobin.
E) binding of O₂by hemoglobin would cease.

Question 55

Hemoglobin binds most strongly to ____.

A) oxygen
B) carbon monoxide
C) carbon dioxide
D) carbonic acid
E) bicarbonate ions

Question 56

A man is found dead with no marks on his body in a small enclosed furnace closet. The medical examiner rules death by hypoxia. However, the criminal investigation finds that the room has adequate air flow. What is the most reasonable explanation for the cause of death that should be investigated further?

A) There was too little oxygen in the room.
B) The furnace was faulty and burned up all the oxygen.
C) The furnace was faulty and released carbon monoxide, which accumulated in the closet.
D) There was too much carbon dioxide in the room.
E) The man strangled himself but the rope disappeared.

Question 57

Some deer mice are physiologically adapted to live at high altitudes because ____.

A) adults maintain fetal forms of hemoglobin
B) of mutations in hemoglobin that increase its oxygen-binding affinity
C) of mutations in myoglobin that increase its oxygen-binding affinity
D) of mutations that increase heart rates
E) of mutations that decrease heart rates

Question 58

The function of carbonic anhydrase is to increase the rate ____.

A) of conversion of CO₂and H₂O into HCO₃- and H⁺
B) of conversion of HCO₃- and H⁺into CO₂and H₂O
C) at which CO₂binds to hemoglobin
D) at which O₂binds to hemoglobin
E) of conversion of HCO₃- and H⁺into CO₂and H₂O, and the rate at which CO₂binds to hemoglobin

Question 59

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

Question 60

Most O₂is 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

Question 61

Respiratory neurons from the dissected brainstem of a neonatal rodent can maintain rhythmic firing for ____ hours.

A) 0.5
B) 1.0
C) 4.5
D) 6.0
E) 8.5

Question 64

Research indicates that the Tibetan and Han Chinese inherited a variant EPAS1 allele from ____.

A) a common Denisovan ancestor
B) interbreeding with Denisovans while still a common ancestral group
C) interbreeding with Denisovans as distinct groups with overlapping territories
D) an ancestor common to all humans
E) an ancestor shared with the Andean people

Question 65

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.

Question 66

Which mechanism is used to encourage the movement of water over gills?

A) beating of cilia
B) contraction of the diaphragm
C) relaxation of a muscular mantle
D) a fish swimming with its mouth closed
E) relaxation of body muscles

Question 67

Alveoli are the respiratory surfaces of birds.

Question 68

When the diaphragm contracts , it moves up into the thoracic cavity, thereby decreasing its volume.

Question 69

Which breathing abnormalities can occur in neonatal mammals exposed to nicotine?

A) reduced ventilatory output
B) increased duration of apneas
C) SIDS
D) reduced ventilatory output and increased duration of apneas
E) reduced ventilatory output, increased duration of apneas, and SIDS

Question 70

Changes in humans caused by high altitude exposure are ____.

A) always temporary
B) always permanent
C) temporary or permanent depending on duration of exposure
D) temporary or permanent depending on developmental timing of exposure
E) temporary or permanent depending on duration and developmental timing of exposure

Question 71

Birds utilize mechanisms similar to countercurrent exchange to optimize diffusion of O₂across their respiratory surfaces.

Question 72

The circulatory surface provides the interface between the body and the respiratory medium.

Question 73

Marine mammals use ____ to extend dive times.

A) decreased blood volume
B) increased erythrocyte count
C) increased in lung volume
D) reduced concentrations of muscle myoglobin
E) elevated circulation to nonessential organs

Question 74

The ____ of marine mammals receives normal blood supply during deep dives.

A) lungs
B) heart
C) brain
D) blood vessels
E) heart, brain, and blood vessels

Question 75

Studies indicate that in utero nicotine exposure can cause breathing abnormalities in neonatal mammals, including ____.

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

Question 76

Describe three adaptations that enhance the function of a respiratory surface.

Question 77

Figure 46.2 (question 99)
Answer the question using the accompanying figure. Llamas, which are customarily known as mountain dwellers, have hemoglobin with higher O₂binding affinity than that of humans. How would the llama hemoglobin-O₂dissociation curve differ from that of a human?

Question 78

Blood O₂levels have the greatest influence on mammalian breathing rate.

Question 79

Tibetan people have ____ in their blood despite living at high altitude.

A) less oxygen
B) more erythropoietin
C) less erythropoietin
D) more hemoglobin
E) less hemoglobin

Question 80

Which animal uses positive pressure breathing to ventilate its lungs?

A) human
B) lizard
C) bird
D) cat
E) salamander