Deck 18: Gas Exchange and Transport

Question 1

The partial pressure of oxygen in arterial blood is approximately ________ mm Hg.

A) 40
B) 45
C) 50
D) 70
E) 100

Answer 1

E

Question 2

If the partial pressure of oxygen in both air and water is 100 mm Hg,then the concentration of the oxygen is the same in the air and water.

Answer 2

False

Question 3

Most of the oxygen transported by the blood is

A) dissolved in plasma.
B) bound to hemoglobin.
C) in ionic form as solute in the plasma.
D) bound to a plasma protein.
E) carried by white blood cells.

Answer 3

B

Question 4

Hypoxia resulting from fluid accumulation in the alveoli that cannot be corrected by oxygen therapy can lead to

A) emphysema.
B) fibrotic lung disease.
C) asthma.
D) adult respiratory distress syndrome.
E) sudden infant death syndrome.

Question 5

Which of the following would make the oxygen-hemoglobin curve shift right?

A) increased H⁺ concentration
B) increased pH
C) decreased temperature
D) decreased CO₂
E) None of the answers are correct.

Question 6

Which of the following characteristics makes hemoglobin's structure such a good match for its function as an oxygen carrier?

A) Each hemoglobin molecule can bind one oxygen molecule.
B) Each hemoglobin molecule can bind two oxygen molecules.
C) Each hemoglobin molecule can bind four oxygen molecules.
D) Each hemoglobin molecule can't be saturated by oxygen molecules.
E) Each hemoglobin binds irreversibly to an oxygen molecule.

Question 7

The process by which dissolved gases are exchanged between the blood and interstitial fluids is

A) pulmonary ventilation.
B) external respiration.
C) diffusion.
D) cellular respiration.
E) breathing.

Question 8

The expiratory neurons control the ________ muscles,whereas the inspiratory neurons control the ________ muscles.

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

Question 9

Most of the carbon dioxide in the blood is transported as

A) solute dissolved in the plasma.
B) carbaminohemoglobin.
C) bicarbonate ions.
D) solute dissolved in the cytoplasm of red blood cells.
E) carbonic acid.

Question 10

The partial pressure of carbon dioxide in the cells of peripheral tissues is approximately ________ mm Hg.

A) 40
B) 45
C) 50
D) 70
E) 100

Question 11

Chronic hypoxia

A) increases 2,3-DPG production in blood.
B) shifts the HbO₂ dissociation curve to the left.
C) can be caused by anemia.
D) increases 2,3-DPG production in blood and can result from anemia.
E) All of the answers are correct.

Question 12

The most important chemical regulator of respiration is

A) oxygen.
B) carbon dioxide.
C) bicarbonate ion.
D) sodium ion.
E) hemoglobin.

Question 13

The variables of oxygen consumption,cardiac output,and blood oxygen content are unrelated.

Question 14

The lung pathology most likely to result from certain kinds of heart disease is

A) emphysema.
B) asthma.
C) pulmonary edema.
D) fibrotic lung disease.
E) lung cancer.

Question 15

An increase in the level of carbon dioxide in the blood will

A) decrease the rate of breathing.
B) increase the rate of breathing.
C) decrease pulmonary ventilation.
D) decrease the alveolar ventilation rate.
E) increase the pH of arterial blood.

Question 16

High carbon dioxide concentration in body fluids is called

A) carbonation.
B) hyperdioxia.
C) hyperoxia.
D) hypercarbia.
E) hypercapnia.

Question 17

In the medulla oblongata,the nucleus tractus solitarius contains the ________ of neurons.

A) pontine respiratory group
B) ventral respiratory group
C) dorsal respiratory group
D) pre-Botzinger complex

Question 18

If the neural connections between the pons and medulla are severed,breathing will stop.

Question 19

Of the factors that influence diffusion of respiratory gases,the most variable and,therefore,important factor to consider is the

A) concentration gradient.
B) diffusion distance.
C) membrane surface area.
D) membrane thickness.
E) electrical charge.

Question 20

At a P_O2 of 70 mm Hg and normal temperature and pH,hemoglobin is ________% saturated with oxygen.

A) 10
B) 25
C) 50
D) 75
E) over 90

Question 21

________ is characterized by a thickened alveolar membrane,slowing respiratory gas exchange.

Question 22

Match the lung disease to its description.
A.fibrotic lung disease
B.emphysema
C.asthma
D.pulmonary edema
decreased surface area for gas exchange

Question 23

Protective reflexes of the lungs include

A) coughing.
B) bronchoconstriction.
C) bronchodilation.
D) bronchodilation and coughing.
E) coughing and bronchoconstriction.

Question 24

Match the factor with its effect on the affinity of hemoglobin for oxygen.
A.increase
B.decrease
increased 2,3-DPG

Question 25

Match the factor with its effect on the affinity of hemoglobin for oxygen.
A.increase
B.decrease
increased temperature

Question 26

Diffusion rate is directly proportional to ________ and ________.

Question 27

Too little oxygen in cells is called ________.

Question 28

Match the lung disease to its description.
A.fibrotic lung disease
B.emphysema
C.asthma
D.pulmonary edema
thickened alveolar membrane and decreased lung compliance

Question 29

Generally,P_O2 in arterial blood is ________ than P_O2 in venous blood.

Question 30

Match the lung disease to its description.
A.fibrotic lung disease
B.emphysema
C.asthma
D.pulmonary edema
fluid accumulation in interstitial spaces

Question 31

Match the lung disease to its description.
A.fibrotic lung disease
B.emphysema
C.asthma
D.pulmonary edema
increased diffusion distance

Question 32

Too little oxygen in cells is often accompanied by too much ________,which is called ________.

Question 33

Match the factor with its effect on the affinity of hemoglobin for oxygen.
A.increase
B.decrease
increased P_CO2

Question 34

________ is characterized by a decreased surface area for gas exchange in the lungs.

Question 35

Match the factor with its effect on the affinity of hemoglobin for oxygen.
A.increase
B.decrease
increased pH

Question 36

The Hering-Breuer reflex

A) functions to increase ventilation with changes in blood pressure.
B) alters pulmonary ventilation when the P_O2 changes.
C) alters pulmonary ventilation when the P_CO2 changes.
D) prevents overexpansion of the lungs.
E) is an important aspect of normal, quiet breathing.

Question 37

Match the lung disease to its description.
A.fibrotic lung disease
B.emphysema
C.asthma
D.pulmonary edema
increased airway resistance

Question 38

P_CO2 tends to be ________ in tissues than in systemic capillaries.

Question 39

Match the lung disease to its description.
A.fibrotic lung disease
B.emphysema
C.asthma
D.pulmonary edema
destruction of alveoli

Question 40

Generally,P_CO2 in arterial blood is ________ than P_CO2 in venous blood.

Question 41

The carotid and aortic bodies contain specialized ________ cells,which can increase ventilation in response to changes in P_O2,P_CO2,or pH.

Question 42

Specialized ________ in the carotid and aortic bodies are activated by a decrease in P_O2 and pH or an increase in P_CO2.What do they trigger?

Question 43

________ is the enzyme that converts CO₂ into bicarbonate ions.

Question 44

What force(s)move(s)carbon dioxide from the blood into the alveoli?

Question 45

List and explain the factors that influence gas diffusion in the lungs.

Question 46

List and explain the factors that influence the presence of gases in liquids.

Question 47

A molecule that blocks the activity of carbonic anhydrase would

A) interfere with oxygen binding to hemoglobin.
B) cause an increase in blood pH.
C) increase the amount of bicarbonate formed in the blood.
D) decrease the amount of carbon dioxide dissolved in the plasma.
E) All of the answers are correct.

Question 48

A student in your lab volunteers to enter a hypoxic breathing chamber for 10 minutes,and his alveolar P_O2 drops to 50 mm Hg.What other change would occur?

A) decrease in arterial pH
B) decrease in arterial P_CO2
C) decrease in pH of cerebrospinal fluid
D) increase in alveolar P_CO2
E) hypoventilation

Question 49

Name three pathological changes that adversely affect gas exchange.

Question 50

What are the three ways CO₂ is transported in blood? Approximately what percentage is transported by each way?

Question 51

Carbon dioxide is more soluble in water than oxygen.To get the same amount of oxygen to dissolve in plasma as carbon dioxide,you would have to

A) decrease the temperature of the plasma.
B) increase the partial pressure of oxygen.
C) decrease the partial pressure of nitrogen.
D) increase the rate of plasma flow through the lungs.
E) decrease the alveolar ventilation rate.

Question 52

In ________,fluid accumulates in the interstitial spaces of the lungs,slowing gas exchange.

Question 53

The output of the ________ group of inspiratory neurons controls the ________ muscle(s)by way of the ________ nerve.

Question 54

________ is characterized by an increased airway resistance and decreased ventilation.

Question 55

Jill lives in St.Louis,which is close to sea level.She decides to spend a month of her summer vacation working in the mountains outside of Denver.After a week in the mountains,what kinds of changes would you expect to see as Jill adapts to the higher altitude?

A) decreased hematocrit
B) decreased blood pressure
C) decreased alveolar ventilation rate
D) decreased P_O2 in the alveoli
E) All of the answers are correct.

Question 56

For maximum efficiency in loading oxygen at the lungs,

A) the pH should be slightly acidic.
B) the temperature should be slightly lower than normal body temperature.
C) the P_O2 should be about 70 mm.
D) DPG levels in the red blood cells should be high.
E) All of the answers are correct.

Question 57

Fear and excitement may affect the pace and depth of respiration by stimulation of portions of the ________.

Question 58

Inappropriate relaxation of the ________ muscles during sleep contributes to ________,a sleep disorder associated with snoring.

Question 59

The ________ group of neurons contains mostly inspiratory neurons.The ________ group of neurons controls muscles used for active expiration and some inspiratory muscles.

Question 60

Diffusion rate is indirectly proportional to ________.

Question 61

An industrious 10-year-old swimmer has attached an extension to his snorkel tube,so that he can sit on the bottom of the ocean for a longer period of time,watching the fish of the coral reef.What problems would you expect him to have? Assuming he is successful in breathing this way for a little while,what are some of the differences he will experience compared to normal breathing?

Question 62

List,compare,and contrast the locations and stimuli for respiratory chemoreceptors.

Question 63

List,compare,and contrast the brain's centers for monitoring and controlling respiration.

Question 64

Draw a flow chart that shows the components of the reflex in which an increase in blood P_CO2 leads to increased ventilation.

Question 65

Drowning is often the introduction of outside water into the alveoli,yet some water is normally present in alveoli.Why is water normally present in the alveoli? What is present in alveolar fluid,besides water,that aids in respiration? What properties of water are detrimental to respiration? What causes drowning? While extremely rare,there have even been documented cases of people walking away from recreational swimming only to die later,on dry land,as a result of drowning (termed "delayed" or "secondary" drowning).Propose an explanation for delayed drowning.

Question 66

Hemoglobin binds to and has a much higher affinity for carbon monoxide (CO)than for oxygen.CO is colorless and odorless and can be produced in homes heated by natural gas; victims usually do not realize they are being poisoned and often die in their sleep.Describe the likely changes in a CO poisoning victim.

Question 67

The chloride shift occurs when

A) hydrogen ions leave the red blood cells.
B) hydrogen ions enter the red blood cells.
C) bicarbonate ions enter the red blood cells.
D) bicarbonate ions leave the red blood cells.
E) carbonic acid is formed.

Question 68

Describe the problems that result in low arterial oxygen content.

Question 69

Timmy is a cantankerous toddler who has just threatened that he will hold his breath until Mom gives him some chocolate.His mother refuses to be manipulated and watches in amusement as Timmy stubbornly refuses to breathe.To her horror,Timmy loses consciousness and collapses onto the floor.Her cousin,who is enrolled in a course for emergency medical technical (EMT)training,is visiting,and tells her there is no need to call for an ambulance.Why did Timmy lose consciousness? Should his mother trust her instincts and call for help and begin CPR,or should she listen to her well-meaning but young and inexperienced cousin? Explain.

Question 70

In the science fiction movie The Abyss,a diver is able to breathe while his head is immersed in a specially prepared liquid pumped into a water-tight helmet attached to a suit,thus allowing him to dive without an air tank and at greater depths than possible for scuba divers.Is this purely fiction,or is it at least theoretically possible? Explain,considering the nature of alveoli and alveolar gas exchange.Assuming it is possible,describe the composition and nature of the liquid in terms of its oxygen pressure and concentration.

Question 71

Do the factors affecting affinity of hemoglobin for oxygen have the same impact on loading and unloading in lungs and tissues? Explain your answer,and indicate if this presents a conflict in remedying hypoxia.Assuming a medical team has treatments available for changing all the factors affecting hemoglobin's oxygen affinity,how should they manipulate pH,temperature,P_CO2,and 2,3-DPG content in a hypoxic patient?

Question 72

Blocking afferent action potentials from the chemoreceptors in the carotid and aortic bodies would interfere with the brain's ability to regulate breathing in response to all EXCEPT which of the following?

A) changes in P_CO2
B) changes in P_O2
C) changes in pH due to carbon dioxide levels
D) changes in blood pressure
E) All of the answers are correct.

Question 73

Write the chemical equation catalyzed by the enzyme carbonic anhydrase.Suppose the concentration of H⁺ is increased by an outside force in a solution that had been at equilibrium.According to the law of mass action,what must happen to the CO₂ concentration to reestablish equilibrium after this disturbance? What must happen to the concentration of bicarbonate?

Question 74

What are the two possible causes of lower alveolar P_O2? Give examples of each.

Question 75

Explain how oxygen and carbon dioxide are transported in the blood.How does the means of transport relate to the solubility and chemical reactivity of these gases in plasma?

Question 76

Compare and contrast carbon monoxide (CO)poisoning,in which CO displaces oxygen from hemoglobin,and metabolic poisoning such as by cyanide.

Question 77

A chemistry student accidentally spills chlorine bleach into a dilute acid.The mixture reacts and produces fumes that are inhaled by the student and that reduce his ventilation.Assume that the gaseous chemical produced is a base (i.e.,it releases OH- in an aqueous solution),and that the chemical is absorbed into the bloodstream at the alveoli.Explain why ventilation is reduced in the patient.

Question 78

Cary deliberately hyperventilates for several minutes before diving into a swimming pool.Shortly after he enters the water and begins swimming,he blacks out and almost drowns.What caused this to happen?

Question 79

Which is typically more important in regulating the respiratory system,P_O2 or P_CO2? Explain your answer and briefly discuss the receptors involved.Give examples of situations in which each of those factors changes enough to stimulate a reflex.How and why are these factors related to each other?

Question 80

You are a scientist who has been hired to write a screenplay for a popular TV series.The plot involves the discovery by a rogue botanist of a plant toxin that interferes with the function of the exchange pump responsible for the chloride shift.This scientist provides the toxin to bioterrorists.What should you write for the coroner to say about symptoms in the poisoning victims?