Deck 46: Gas Exchange

Question 1

The countercurrent exchange system found in fish gills maximizes gas exchange efficiency by:

A) producing rapid water flows across the gill surface.
B) allowing water and blood to come in direct contact to maximize oxygen exchange.
C) having a high concentration gradient of oxygen at the start of the capillaries.
D) maintaining a high concentration gradient of oxygen along the entire length of capillaries.
E) decreasing the oxygen content of the blood leaving the gill filaments.

Answer 1

D

Question 2

Which of the following animals have lungs that have millions of alveoli that increase the surface available for gas exchange?

A) Mammals
B) Birds
C) Fish
D) Salamanders
E) Lizards

Answer 2

A

Question 3

Parabronchi are characteristic of:

A) insects.
B) spiders.
C) mollusks.
D) birds.
E) mammals.

Answer 3

D

Question 4

What is the approximate maximum thickness of an animal that allows oxygen to diffuse quickly enough through the layers of cells to support life?

A) 100 mm
B) 10 mm
C) 1 mm
D) 100 m m
E) 10 m m

Question 5

Sponges, hydras, flatworms, and many other small, aquatic organisms exchange gases entirely by which of the following processes?

A) Diffusion
B) Organismic respiration
C) Aerobic cellular respiration
D) Catabolism
E) Anabolism

Question 6

The process of gas exchange in parabronchi is similar to:

A) osmosis in spiracles.
B) respiration in tracheal tubes.
C) concurrent exchange in gills.
D) diffusion in small animals.
E) countercurrent exchange in gills.

Question 7

In the process of organismic respiration:

A) oxygen is extracted from the environment by the organism and delivered to its cells.
B) the citric acid cycle takes place in the cells.
C) carbohydrates are broken down and electrons are transferred to oxygen.
D) there is an accumulation of lactic acid in the tissues due to the absence of oxygen.
E) carbon dioxide is produced in the Krebs cycle.

Question 8

The ventilation of insect tracheal tubes is dependent upon the presence of:

A) pores.
B) alveoli.
C) gills.
D) spiracles.
E) opercula.

Question 9

In fish, blood flows in a direction opposite to the flow of water over the gills in a process known as:

A) concurrent exchange.
B) countercurrent exchange.
C) crosscurrent exchange.
D) exhalation.
E) diffusion.

Question 10

Figure 46-1 ​

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Refer to the accompanying figure. Which two figures in the accompanying illustration represent inhalation steps of the respiratory cycle?

A) 1 and 3
B) 1 and 2
C) 2 and 3
D) 2 and 4
E) 3 and 4

Question 11

Mitochondria use respired oxygen as an electron acceptor in the process known as:

A) pulmonary ventilation.
B) cellular respiration.
C) external respiration.
D) internal respiration.
E) anaerobic respiration.

Question 12

Which of the following is a disadvantage of gas exchange in water, as compared to gas exchange in air?

A) Air is less dense than water.
B) Air contains a higher concentration of oxygen.
C) Less energy is needed to move air over a gas exchange surface.
D) Oxygen diffuses more slowly through water than air.
E) Air is less viscous than water.

Question 13

Figure 46-1 ​

​
Refer to the accompanying figure. Place Figures 1-4 in the correct order to represent the two-cycle breathing process of birds.

A) 1 → 2 → 3 → 4
B) 2 → 3 → 4 → 1
C) 2 → 3 → 1 → 4
D) 3 → 2 → 1 → 4
E) 4 → 3 → 2 → 1

Question 14

Clams and other bivalves typically have:

A) dermal gills.
B) gills adapted for trapping food.
C) an operculum.
D) book lungs.
E) swim bladders.

Question 15

In the countercurrent exchange system, the percentage of available oxygen extracted from the blood exceeds 80%. What would this percentage be if oxygen were instead obtained through concurrent exchange?

A) 40%
B) 50%
C) 60%
D) 80%
E) 100%

Question 16

Why do land dwelling insects drown when they are in water?

A) Their lungs fill with water.
B) Their lungs are functioning too fast to sustain life.
C) They cannot respire across their body surface.
D) They are unable to ventilate because their spiracles are underwater.
E) Their gills are too moist.

Question 17

Some amphibians:

A) may exchange gases across their body surfaces.
B) have fairly simple, book lungs.
C) have gills and swim bladders, homologous to those found in fishes.
D) are characterized by having parabronchi across which most of the gas exchange occurs.
E) have a large oxygen demand that is met by using a countercurrent gas exchange mechanism.

Question 18

Which of the following is a disadvantage of gas exchange in air, as opposed to gas exchange in water?

A) Air is denser than water
B) Threat of desiccation
C) High metabolic cost of acquiring oxygen
D) Lack of diffusion
E) Kinetic limitations

Question 19

Which of the following sequences correctly describes the movement of air in a bird's respiratory system?

A) Lungs; anterior air sacs; posterior air sacs
B) Anterior air sacs; posterior air sac; lungs
C) Posterior air sacs; lungs; anterior air sacs
D) Lungs; posterior air sacs; anterior air sacs
E) Anterior air sacs; lungs; posterior air sacs

Question 20

Which animal gets fresh air across the lungs through both inhalation and exhalation?

A) Amphibians
B) Birds
C) Fish
D) Insects
E) Mammals

Question 21

Figure 46-3 ​

​
Refer to the accompanying figure. Which statement is FALSE?

A) The of the air in the alveoli must be greater than 100 mm Hg.
B) The  in the tissues must be less than 100 mm Hg.
C) The of the air in the alveoli must be less than 40 mm Hg.
D) The in the tissues must be greater than 40 mm Hg.
E) The in the tissues must be equal to the 
 in the tissues.

Question 22

The volume of air remaining in the lungs after maximal expiration is the:

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

Question 23

Which of the following best defines the Bohr effect?

A) The amount of a gas that diffuses across a membrane depends on the differences in the gas's partial pressure.
B) The ability of hemoglobin to bind oxygen depends on the partial pressure of oxygen.
C) In a mixture of gases, the total pressure of the mixture is the sum of the pressures of the individual gases.
D) pH causes a displacement of the oxygen-hemoglobin dissociation curve.
E) As the concentration of chloride ions increases, the ability of hemoglobin to bind carbon dioxide decreases.

Question 24

Suppose the oxygen concentration in your tissues were high. Which of the following correctly describes how this would change the reaction of hemoglobin with O₂?

A) Shift to the left (to reactants)
B) Shift to the right (to products)
C) No change in equilibrium
D) Speed up
E) Slow down

Question 25

Figure 46-2 ​

​
Refer to the accompanying figure. Which of these lungs would be best for an animal that is fairly active?

A) 1
B) 2
C) 3
D) 4
E) Any of these.

Question 26

The percent oxygen saturation of hemoglobin is highest in the:

A) tissues where oxygen concentration is lowest.
B) tissues where oxygen concentration is highest.
C) venules where oxygen concentration is lowest.
D) pulmonary capillaries where oxygen concentration is lowest.
E) pulmonary capillaries where oxygen concentration is highest.

Question 27

Figure 46-3 ​

​
Refer to the accompanying figure. Which statement is accurate?

A) CO₂ will diffuse from the alveoli into the capillaries.
B) CO₂ will diffuse from the capillaries into the tissues.
C) O₂ will diffuse from the capillaries in the tissues to the capillaries in the lung.
D) O₂ will diffuse from the alveoli into the capillaries.
E) O₂ will diffuse from the tissues into the capillaries.

Question 28

During respiratory exchange, carbon dioxide moves from the blood into the alveoli due to:

A) the presence of a permease, which removes carbon dioxide from the capillaries.
B) potassium cotransport.
C) diffusion down a concentration gradient.
D) the air pressure of dissolved oxygen, which forces it out.
E) the contraction of the diaphragm, which creates a vacuum that pulls it out.

Question 29

Which of the following occurs during forced expiration?

A) The alveoli inflate.
B) The ribs move upward.
C) The internal intercostal muscles contract.
D) The floor of the thoracic cavity moves downward.
E) The pressure increases in the thoracic cavity.

Question 30

Dalton's Law states that:

A) the amount of a gas that diffuses across a membrane depends on the differences in the gas's partial pressure.
B) the ability of hemoglobin to bind oxygen depends on the partial pressure of oxygen.
C) in a mixture of gases, the total pressure of the mixture is the sum of the pressures of the individual gases.
D) pH causes a displacement of the oxygen-hemoglobin dissociation curve.
E) as the concentration of chloride ions increases, the ability of hemoglobin to bind carbon dioxide decreases.

Question 31

In birds, the parabronchi capillaries are oriented at right angles to the parabronchi. Which of the following is the gas exchange method that describes this process?

A) Crosscurrent
B) Countercurrent
C) Concurrent
D) Diffusion
E) Equilibrium

Question 32

The amount of air that is moved with each ventilation is referred to as:

A) vital capacity.
B) tidal volume.
C) residual capacity.
D) the Bohr effect.
E) hyperventilation.

Question 33

Which of the following is typically used to measure the functional capacity of the lungs?

A) Vital capacity
B) Tidal volume
C) Tidal capacity
D) Residual capacity
E) Residual volume

Question 34

Figure 46-2 ​

​
Refer to the accompanying figure. Which of these lungs would have the greatest surface area?

A) 1
B) 2
C) 3
D) 4
E) All have equal surface area.

Question 35

Figure 46-1 ​

​
Refer to the accompanying figure. The structures receiving air in Figure 1 are known as:

A) anterior air sacs.
B) parabronchi.
C) spiracles.
D) alveoli.
E) tracheae.

Question 36

Fick's law states that:

A) the amount of gas diffusing across a membrane depends on differences in partial pressure.
B) the total pressure of a mixture of gases is the sum of the pressures of the individual gases.
C) the dissociation of oxygen from hemoglobin depends on the pH of the environment.
D) as oxygen concentration increases, there is an increase in the amount of hemoglobin produced.
E) the size of an animal varies inversely to the amount of diffusion across its respiratory membranes.

Question 37

Hemocyanin:

A) combines irreversibly with oxygen for transport within the body of various organisms.
B) is bright red in color when combined with oxygen.
C) has an iron-porphyrin group that is responsible for oxygen transport.
D) is a respiratory pigment found in the blood of some invertebrate and vertebrate species.
E) is a respiratory pigment that is colorless when deoxygenated.

Question 38

Figure 46-2 ​

​
Refer to the accompanying figure. Which of these lungs would be found in reptiles?

A) 1 only
B) 2 only
C) 3 only
D) 4 only
E) both 1 and 2

Question 39

Figure 46-4 ​

Oxygen-hemoglobin dissociation curves at three different pH levels
​
The phenomenon illustrated in the accompanying figure is known as:

A) carbon dioxide unloading.
B) the Bohr effect.
C) hemoglobin transportation.
D) chloride shift.
E) residual capacity.

Question 40

The maximum amount of air a person can exhale is called:

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

Question 41

The film of fluid in the pleural cavity functions to:

A) nourish the lungs.
B) rehydrate the lungs.
C) provide lubrication between the lungs and thoracic wall.
D) trap bacteria that may enter the lungs.
E) inflate the lungs.

Question 42

Cilia lining the respiratory tubes beat mucus upward in order to:

A) moisten the bronchioles.
B) conduct the mucus that contains particles to the pharynx and away from the lungs.
C) provide mucus to the lungs to prevent them from dehydrating.
D) lubricate the throat for easier swallowing.
E) promote gas exchange by providing mucus for the respiratory surfaces.

Question 43

Decompression sickness is caused by:

A) dissolved gases coming out of solution and forming gas bubbles.
B) the concentration of hemoglobin dropping markedly.
C) chloride ions precipitating from solution.
D) the pH of the blood rising too rapidly.
E) carbonic anhydrase being inhibited.

Question 44

Which of the following is the normal tidal volume in an adult human?

A) 1 mL
B) 10 mL
C) 50 mL
D) 100 mL
E) 500 mL

Question 45

The pleural cavity is located:

A) between the pleural membranes.
B) inside the innermost pleural membrane.
C) outside the outermost pleural membrane.
D) between the right lung and the left lung.
E) within the bronchioles.

Question 46

Which of the following areas of the respiratory tract is lined with a single layer of epithelial cells?

A) Nasal cavity
B) Larynx
C) Trachea
D) Bronchi
E) Alveoli

Question 47

Most of the carbon dioxide in the blood is transported:

A) by being dissolved in plasma.
B) as bicarbonate ions.
C) by hemoglobin.
D) as carbonic anhydrase.
E) as carbonic acid.

Question 48

What will happen if a carbonic anhydrase inhibitor is added to blood?

A) The level of CO₂ in the blood will increase.
B) The level of CO₂ in the blood will decrease.
C) The level of CO₂ in the blood will remain the same.
D) The pH of the blood will remain the same.
E) The pH of the blood will decrease.

Question 49

Carbonic anhydrase in red blood cells:

A) removes oxygen from the erythrocyte.
B) carries carbon dioxide in the erythrocyte.
C) converts carbon dioxide to carbonic acid.
D) increases the pH of the blood.
E) increases the permeability of the capillary to carbon dioxide.

Question 50

The voice box is also referred to as the:

A) larynx.
B) nasal cavity.
C) epiglottis.
D) pharynx.
E) trachea.

Question 51

What happens at higher altitudes?

A) The concentration of oxygen decreases.
B) The concentration of carbon dioxide increases.
C) The partial pressure of oxygen decreases.
D) The partial pressure of carbon dioxide increases.
E) There is no change in the concentration or partial pressures of atmospheric gases.

Question 52

The ability of oxygen to combine with and detach from hemoglobin is influenced by which of the following factors?

A) Percent oxygen saturation
B) Humidity
C) Oxygen concentration
D) Tidal volume
E) Partial pressure

Question 53

In the blood, most (60%) of the carbon dioxide moves through plasma as which of the following substances?

A) Bicarbonate
B) Lactic acid
C) Carbonic acid
D) Formic acid
E) Acetate

Question 54

When drinking water at a party, you sneeze and water comes out of your nose. Why did this happen?

A) The epiglottis did not close.
B) The glottis did not close.
C) The pharynx and nasal cavity were connected.
D) The tongue blocked the pharynx.
E) The water was carbonated.

Question 55

Hypoxia is defined as which of the following?

A) Deficiency of carbon dioxide
B) Deficiency of nitrogen
C) Deficiency of oxygen
D) Deficiency of hydrogen
E) Deficiency of water

Question 56

Which of the following is the general name for any medical condition that interferes with the removal of carbon dioxide by the lungs?

A) Respiratory acidosis
B) Respiratory alkylosis
C) Chloride shift
D) Bohr effect
E) Anemia

Question 57

The smallest branches of the respiratory tree are the:

A) pharynx.
B) tracheae.
C) bronchial tubes.
D) bronchioles.
E) bronchi.

Question 58

Specialized chemoreceptors in the medulla, walls of the aorta, and the walls of the carotid arteries are sensitive to SMALL changes in the arterial concentration of which of the following substances?

A) N₂
B) O₂
C) H₂
D) H₂O
E) CO₂

Question 59

Which statement about the regulation of respiration is FALSE?

A) Respiratory centers in the medulla control the transition from inspiration to expiration.
B) Carbon dioxide concentration is the most important chemical stimulus for regulating respiratory rate.
C) Chemoreceptors in the walls of various arteries are sensitive to carbon dioxide levels in the blood.
D) A group of neurons in the ventral medulla only become active when we need to breathe forcefully.
E) Chemoreceptors may be sensitive to oxygen, carbon dioxide, and/or hydrogen ion concentration.

Question 60

Oxygen concentration generally plays an important role in regulating respiration:

A) all the time.
B) never.
C) only when the carbon dioxide concentration falls markedly.
D) only when the oxygen concentration falls markedly.
E) only when the pH falls markedly.

Question 61

The single most preventable cause of disease in the United States is:

A) alcohol use.
B) tobacco use.
C) automobile accidents.
D) suicide.
E) homicide.

Question 62

The swim bladders of fishes function primarily in ventilation.

Question 63

During inhalation, the diaphragm moves upward.

Question 64

Gases move freely across the walls of the bronchioles into the capillaries that surround them.

Question 65

During exhalation, air moves from the bronchi directly into the alveoli.

Question 66

Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the pressures of the individual gases.

Question 67

Which of the following occurs in pulmonary emphysema?

A) The alveoli lose their elasticity.
B) The surface area of the lung is greatly decreased.
C) Walls between adjacent alveoli become reinforced.
D) The heart becomes enlarged from pressure.
E) Fresh air accumulates in the lungs because it cannot be properly inhaled.

Question 68

The parabronchi of birds are open at both ends.

Question 69

The efficient exchange of gases in gills is an example of countercurrent exchange.

Question 70

Compare and contrast the advantages and disadvantages of gas exchange in terrestrial and aquatic environments.

Question 71

Pulmonary surfactant functions by:

A) increasing the cohesive forces of water molecules.
B) increasing the surface tension of water.
C) moving water across respiratory surfaces.
D) preventing the alveoli from expanding.
E) increasing the energy required to stretch the lungs.

Question 72

Tracheal tubes and spiracles are characteristically found in annelids.

Question 73

Identify and briefly explain two adaptations of diving marine mammals, such as seals and dolphins.

Question 74

The amount of oxygen or carbon dioxide that diffuses across the membrane of an alveolus depends both on the differences in partial pressure on both sides of the membrane and on the surface area of the membrane. This describes which of the following?

A) Stokes-Einstein equation
B) Dalton's law of partial pressures
C) Charles's law
D) Fick's law of diffusion
E) Ideal gas law

Question 75

You have a significant reduction in the amount of pulmonary surfactant. What is the likely effect?

A) The risk of bacterial infection will increase.
B) The risk of having chronic obstructive pulmonary disease will increase.
C) The bronchioles will constrict, which will increase airway resistance.
D) The lungs will be difficult to inflate.
E) Gas exchange cannot occur.

Question 76

During inhalation, air moves from the pharynx directly into the trachea.

Question 77

Given that the percent nitrogen gas in the air at sea level is 78%, what is the partial pressure of nitrogen gas?

A) 78 mm Hg
B) 100 mm Hg
C) 167 mm Hg
D) 593 mm Hg
E) 780 mm Hg

Question 78

Vocal cords are located in the larynx.

Question 79

Define ventilation, and explain how this process is carried out in terrestrial vertebrates.

Question 80

Arrange the structures through which air passes upon entering the body in the proper sequence. 1) Alveoli
2) Bronchi
3) Larynx
4) Bronchioles
5) Pharynx
6) Trachea

A) 5 → 3 → 6 → 2 → 4 → 1
B) 3 → 5 → 2 → 6 → 1 → 4
C) 2 → 4 → 3 → 5 → 6 → 1
D) 3 → 6 → 5 → 2 → 4 → 1
E) 5 → 6 → 3 → 4 → 2 → 1