Unit 5 - Respiratory System

Question 1

Which is NOT considered to be a primary function of the respiratory system?
A) regulation of water balance
B) regulation of pH balance
C) protection against pathogens
D) vocalization
E) gas exchange

Answer 1

A) regulation of water balance

Question 2

Ventilation is also known as
A) breathing.
B) inspiration.
C) expiration.
D) air conduction.
E) blowing.

Answer 2

A) breathing.

Question 3

The upper respiratory tract includes all EXCEPT which of the following?
A) nasal cavity
B) lungs
C) trachea
D) larynx
E) mouth

Answer 3

B) lungs

Question 4

The lower respiratory tract includes
A) all of the bronchial branches.
B) only the lungs.
C) only the trachea.
D) all of the bronchial branches and the lungs
E) all of the bronchial branches, the lungs, and the trachea.

Answer 4

D) all of the bronchial branches and the lungs

Question 5

Pulmonary ventilation refers to the
A) movement of air into and out of the lungs.
B) movement of dissolved gases from the alveoli to the blood.
C) movement of dissolved gases from the blood to the interstitial space.
D) movement of dissolved gases from the interstitial space to the cells.
E) utilization of oxygen.

Answer 5

A) movement of air into and out of the lungs.

Question 6

Alveolar ventilation refers to the
A) movement of air into and out of the lungs.
B) movement of air into and out of the alveoli.
C) movement of dissolved gases from the alveoli to the blood.
D) movement of dissolved gases from the blood to the alveoli.
E) utilization of oxygen by alveolar cells to support metabolism.

Answer 6

B) movement of air into and out of the alveoli.

Question 7

The actual sites of gas exchange within the lungs are
A) bronchioles.
B) alveolar ducts.
C) pleural spaces.
D) alveoli.
E) terminal sacs.

Answer 7

D) alveoli.

Question 8

Place the following structures of the respiratory tree in the order in which air passes through them.
1. secondary bronchi
2. bronchioles
3. primary bronchi
4. alveoli
5. terminal bronchioles
A) 4, 1, 2, 3, 5
B) 1, 3, 5, 2, 4
C) 3, 1, 5, 2, 4
D) 3, 1, 2, 5, 4
E) 1, 3, 2, 5, 4

Answer 8

D) 3, 1, 2, 5, 4

Question 9

The airway between the larynx and the primary bronchi is the
A) pharynx.
B) bronchiole.
C) trachea.
D) alveolar duct.
E) laryngeal duct.

Answer 9

C) trachea.

Question 10

The lungs are enclosed in \_\_\_\_\_\_\_\_ membranes.
A) pericardial
B) pulmonary
C) pleural
D) thoracic
E) costal

Answer 10

C) pleural

Question 11

The lungs are located in the \_\_\_\_\_\_\_\_ cavity.
A) pericardial
B) pulmonary
C) pleural
D) thoracic
E) costal

Answer 11

D) thoracic

Question 12

Pressure and volume of gas in a container are related to temperature and number of gas molecules. This is known as \_\_\_\_\_\_\_\_ law.
A) the ideal gas
B) Boyle's
C) Dalton's
D) Henry's
E) Ohm's

Answer 12

A) the ideal gas

Question 13

Type II alveolar cells
A) allow rapid diffusion of gases through their thin membranes.
B) secrete a chemical known as surfactant.
C) are phagocytic.
D) allow rapid diffusion of gases through their thin membranes, secrete a chemical known as surfactant, and are phagocytic.
E) None of the statements are true.

Answer 13

B) secrete a chemical known as surfactant.

Question 14

Type I alveolar cells
A) allow rapid diffusion of gases through their thin membranes.
B) secrete a chemical known as surfactant.
C) are phagocytic.
D) allow rapid diffusion of gases through their thin membranes, secrete a chemical known as surfactant, and are phagocytic.
E) None of the statements are true.

Answer 14

A) allow rapid diffusion of gases through their thin membranes.

Question 15

Which of the following features of the alveolar sacs allows for the ease of diffusion of gasses?
A) They are made of a single layer of simple squamous epithelium.
B) Type II alveolar cells secrete surfactant.
C) Elastin fibers allow the alveoli to stretch thin enough for diffusion to occur.
D) They are made of a single layer of simple squamous epithelium and elastin fibers allow the alveoli to stretch thin enough for diffusion to occur.

Answer 15

A) They are made of a single layer of simple squamous epithelium.

Question 16

Surfactant
A) protects the surface of the lungs.
B) phagocytizes small particulate matter.
C) replaces mucus in the alveoli.
D) helps prevent the alveoli from collapsing.
E) is not found in healthy lung tissue.

Answer 16

D) helps prevent the alveoli from collapsing.

Question 17

The common passageway shared by the respiratory and digestive systems is the
A) larynx.
B) glottis.
C) vestibule.
D) pharynx.
E) esophagus.

Answer 17

D) pharynx.

Question 18

When the diaphragm and external intercostal muscles contract,
A) the volume of the thorax increases.
B) the volume of the thorax decreases.
C) the volume of the lungs decreases.
D) the lungs collapse.
E) expiration occurs.

Answer 18

A) the volume of the thorax increases.

Question 19

Dalton’s law states that
A) gas volume and temperature are directly proportional.
B) gas volume and pressure are inversely proportional.
C) the volume of gas that will dissolve in a solvent is proportional to the solubility of the gas and the gas pressure.
D) in a mixture of gases like air, the total pressure is the sum of the individual partial pressures of the gases in the mixture.
E) None of the answers are correct.

Answer 19

D) in a mixture of gases like air, the total pressure is the sum of the individual partial pressures of the gases in the mixture.

Question 20

Air moves into the lungs because
A) the gas pressure in the lungs is less than outside pressure.
B) the volume of the lungs decreases with inspiration.
C) the thorax is muscular.
D) contraction of the diaphragm decreases the volume of the pleural cavity.
E) All of the answers are correct.

Answer 20

A) the gas pressure in the lungs is less than outside pressure.

Question 21

Air moves out of the lungs because
A) the gas pressure in the lungs is less than outside pressure.
B) the volume of the lungs decreases with expiration.
C) the thorax is muscular.
D) contraction of the diaphragm increases the volume of the pleural cavity.
E) All of the answers are correct.

Answer 21

B) the volume of the lungs decreases with expiration.

Question 22

In quiet breathing,
A) inspiration and expiration involve muscular contractions.
B) inspiration is passive and expiration involves muscular contractions.
C) inspiration involves muscular contractions and expiration is passive.
D) inspiration and expiration are both passive processes.
E) None of the answers are correct.

Answer 22

C) inspiration involves muscular contractions and expiration is passive.

Question 23

Boyle's law states that gas volume is
A) directly proportional to pressure.
B) directly proportional to temperature.
C) inversely proportional to pressure.
D) inversely proportional to temperature.
E) None of the answers are correct.

Answer 23

C) inversely proportional to pressure.

Question 24

Air entering the body is filtered, warmed, and humidified by the
A) upper respiratory tract.
B) lower respiratory tract.
C) lungs.
D) alveoli.
E) All of the answers are correct.

Answer 24

A) upper respiratory tract.

Question 25

A typical value for intrapleural pressure is \_\_\_\_\_\_\_\_ mm Hg.
A) +6
B) +3
C) 0
D) -3
E) -6

Answer 25

D) -3

Question 26

According to the law of LaPlace, when comparing two alveoli lined with fluid, pressure in the one with the ________ diameter will be greater.
A) larger
B) smaller

Answer 26

B) smaller

Question 27

When alveolar pressure is equal to atmospheric pressure, air flows into the lungs.
A) True
B) False

Answer 27

B) False

Question 28

Active expiration is produced by contraction of
A) abdominal muscles only.
B) diaphragm only.
C) internal intercostals only.
D) external intercostals only.
E) abdominal muscles and internal intercostals.

Answer 28

E) abdominal muscles and internal intercostals.

Question 29

When the diaphragm and external intercostal muscles contract,
A) expiration occurs.
B) intrapulmonary pressure increases.
C) intrapleural pressure decreases.
D) the volume of the lungs decreases.
E) All of the answers are correct.

Answer 29

C) intrapleural pressure decreases.

Question 30

If a student inhales as deeply as possible and then blows the air out until he cannot exhale any more, the amount of air that he expelled is his
A) tidal volume.
B) inspiratory reserve volume.
C) expiratory reserve volume.
D) minimal volume.
E) vital capacity.

Answer 30

E) vital capacity.

Question 31

Total cross-sectional area ________ with each division of the airways.
A) increases
B) decreases
C) does not change

Answer 31

A) increases

Question 32

Blood vessels cover approximately \_\_\_\_\_\_\_\_% of the alveolar surface.
A) 80-90
B) 10-20
C) > 90
D) < 10
E) 50

Answer 32

A) 80-90

Question 33

In the lungs, the
A) blood flow rate is higher and the blood pressure is lower, respectively, than the blood flow rate and the blood pressure in other tissues.
B) blood flow rate is higher and the blood pressure is higher, respectively, than the blood flow rate and the blood pressure in other tissues.
C) blood flow rate is lower and the blood pressure is lower, respectively, than the blood flow rate and the blood pressure in other tissues.
D) blood flow rate is lower and the blood pressure is higher, respectively, than the blood flow rate and the blood pressure in other tissues.
E) blood flow rate and the blood pressure are the same as in other tissues.

Answer 33

A) blood flow rate is higher and the blood pressure is lower, respectively, than the blood flow rate and the blood pressure in other tissues.

Question 34

The distance between the alveolar airspace and capillary endothelium is ________, allowing gases to diffuse ________ between them.
A) short, rapidly
B) long, rapidly
C) short, slowly
D) long, slowly
E) None of the answers are correct–distance does not affect diffusion rate.

Answer 34

A) short, rapidly

Question 35

Flow of air
A) is directly proportional to a pressure gradient, and flow decreases as the resistance of the system increases.
B) is directly proportional to the resistance, and flow decreases as the pressure of the system increases.
C) is directly proportional to a pressure gradient, and flow increases as the resistance of the system increases.
D) is directly proportional to the resistance, and flow increases as the resistance of the system increases.
E) None of the answers are correct.

Answer 35

A) is directly proportional to a pressure gradient, and flow decreases as the resistance of the system increases.

Question 36

An increase in PCO2 would cause
A) the bronchioles to dilate and the systemic arterioles to dilate.
B) the bronchioles to dilate and the systemic arterioles to constrict.
C) the bronchioles to constrict and the systemic arterioles to dilate.
D) the bronchioles to constrict and the systemic arterioles to constrict.
E) None of the answers are correct.

Answer 36

A) the bronchioles to dilate and the systemic arterioles to dilate.

Question 37

Chronic inhalation of fine particles that reach the alveoli leads to \_\_\_\_\_\_\_\_ lung disease.
A) obstructive
B) restrictive
C) fibrotic
D) compliant
E) congestive

Answer 37

C) fibrotic

Question 38

Poiseuille's law is summarized this way:
A) PV = nRT
B) R   Lη/r4 
C) P = 2T/r
D) P1V1 = P2V2

Answer 38

B) R Lη/r4

Question 39

Histamine's primary role in the respiratory system is as a 
A) surfactant.
B) bronchodilator.
C) bronchoconstrictor.
D) vasodilator.
E) vasoconstrictor.

Answer 39

C) bronchoconstrictor.

Question 40

the additional air inhaled after a normal inspiration

Answer 40

inspiratory reserve volume

Question 41

the minimum amount of air always present in the respiratory system, after blowing out all you can

Answer 41

residual volume

Question 42

the extra amount actively (forcibly) exhaled after a normal exhalation

Answer 42

expiratory reserve volume

Question 43

the amount of air taken in during a single normal inspiration

Answer 43

tidal volume

Question 44

the amount of air remaining in the lungs after a normal breath

Answer 44

functional residual capacity

Question 45

the sum of all the lung volumes

Answer 45

total lung capacity

Question 46

the amount of air inhaled during an active (forced) inspiration

Answer 46

inspiratory capacity

Question 47

the total amount of air that can be exchanged at will

Answer 47

vital capacity

Question 48

The beating of the cilia of the respiratory passages in the direction of the pharynx forms a ________.

Answer 48

mucociliary escalator

Question 49

When the inspiratory muscles relax, the rib cage returns to its original position as a result of ________.

Answer 49

elastic recoil

Question 50

The ease with which the lungs stretch in response to changes in pressure is termed ________.

Answer 50

compliance

Question 51

The ability of a lung to recoil, or recover from stretch, is called ________.

Answer 51

elastance

Question 52

In the disease ________, many symptoms are due to destruction of elastic fibers in the lung.

Answer 52

emphysema

Question 53

Some have a congenital alpha-1 antitrypsin deficiency. If the job of alpha-1 antitrypsin is to inhibit trypsin and elastase, what condition are people with this genetic deficiency likely to develop?

Answer 53

emphysema

Question 54

The substance produced by the lungs to reduce surface tension is called ________.

Answer 54

surfactant

Question 55

The cells of the lung that produce the substance that lowers surface tension are ________

Answer 55

type II alveolar cells

Question 56

Because of their smooth muscle component, the structures of the lower respiratory system that can most alter airway resistance are the ________.

Answer 56

bronchioles

Question 57

A powerful bronchoconstrictor released by mast cells is ________.

Answer 57

histamine

Question 58

Ongoing diseases in which air flow during expiration is diminished are known as ________.

Answer 58

chronic obstructive pulmonary diseases (COPDs)

Question 59

An increase in the rate and depth of breathing is known as ________.

Answer 59

hyperventilation

Question 60

The volume of air moved in a single respiration is called the ________.

Answer 60

tidal volume

Question 61

The volume of air that can be forcefully expelled from the lungs following a normal exhalation is called the ________.

Answer 61

expiratory reserve volume

Question 62

The volume of air that can be forcefully inhaled on top of a normal inspiration is called the ________.

Answer 62

inspiratory reserve volume

Question 63

The volume of air that remains in the lungs after a forced expiration is called the ________.

Answer 63

residual volume

Question 64

A typical residual volume (in milliliters) for a healthy, 70 kg male is ________.

Answer 64

1200 mL

Question 65

The opposing layers of pleural membrane are held together by a thin film of ________.

Answer 65

pleural fluid

Question 66

The larynx contains the ________, connective tissue bands that tighten and vibrate to create sound when air moves past them.

Answer 66

vocal cords

Question 67

The primary function of the alveoli is ________.

Answer 67

the exchange of gases between themselves and the blood

Question 68

A ________ is an instrument that measures the volume of air moved with each breath.

Answer 68

spirometer

Question 69

Air flows into lungs because of ________ created by ________.

Answer 69

pressure gradients, pumps

Question 70

List the muscles of inspiration and expiration.

Answer 70

Inspiration: diaphragm, external intercostals, scalenes, and sternocleidomastoids.

Expiration: internal intercostals, abdominal wall muscles.

Question 71

Explain how the upper airways and bronchi condition the air, and why this conditioning is important.

Answer 71

Air is warmed to body temperature to protect alveoli and avoid disrupting body temperature, air is humidified so that the exchange epithelium will not dehydrate, and foreign material is filtered out so it will not reach the alveoli.

Question 72

During normal expiration,
A) elastic recoil of stretched muscles helps return the thorax to its resting volume.
B) the internal intercostal muscles are required.
C) the abdominal muscles become involved.
D) elastic recoil of stretched muscles helps return the thorax to its resting volume and the internal intercostal muscles are required.
E) elastic recoil of stretched muscles helps return the thorax to its resting volume, the internal intercostal muscles are required, and the abdominal muscles become involved.

Answer 72

A) elastic recoil of stretched muscles helps return the thorax to its resting volume.

Question 73

Damage to the type II cells of the lungs would contribute to
A) a thickening of the respiratory membrane.
B) an increased rate of gas exchange.
C) alveolar rupture.
D) alveolar collapse.
E) decreased surface tension in the water lining the alveoli.

Answer 73

D) alveolar collapse.

Question 74

Harry suffers from cystic fibrosis and frequently has periods where he can hardly breathe. The problem is the result of
A) inflammation of the bronchi.
B) constriction of the trachea.
C) thick secretions that exceed the ability of the mucus elevator to transport them.
D) laryngospasms that occur in response to a toxic substance produced by the epithelial cells.
E) collapse of one or both lungs.

Answer 74

C) thick secretions that exceed the ability of the mucus elevator to transport them.

Question 75

Breathing that involves active inspiratory and expiratory movements is called
A) eupnea.
B) hyperpnea.
C) diaphragmatic breathing.
D) costal breathing.
E) shallow breathing.

Answer 75

B) hyperpnea.

Question 76

The respiratory rate times the tidal volume corrected for dead space is the
A) vital capacity.
B) respiratory minute volume.
C) pulmonary ventilation rate.
D) alveolar ventilation rate.
E) external respiration rate.

Answer 76

D) alveolar ventilation rate.

Question 77

Increasing the alveolar ventilation rate will
A) increase the partial pressure of oxygen in the alveoli.
B) decrease the rate of oxygen diffusion from the alveoli to the blood.
C) increase the partial pressure of carbon dioxide in the alveoli.
D) decrease the rate of carbon dioxide diffusion from the blood to the alveoli.
E) have no effect on either the partial pressure or diffusion rate of gases.

Answer 77

A) increase the partial pressure of oxygen in the alveoli.

Question 78

In the lungs, an example of the body’s reserve capacity is that
A) some areas of the lung can be closed off during rest and opened again when needed during exercise.
B) capillary beds in the lungs are reversibly collapsible, allowing blood to be shunted to additional areas during exercise.
C) pulmonary blood flow is completely under the control of the autonomic nervous system, dilating arteries and arterioles to adjust blood flow.
D) All of the statements are true.
E) None of the statements are true.

Answer 78

B) capillary beds in the lungs are reversibly collapsible, allowing blood to be shunted to additional areas during exercise.

Question 79

Joe is playing in an intramural football game when he is tackled so hard that he breaks a rib. He can actually feel a piece of the rib sticking through the skin, and he is having a difficult time breathing. Joe probably is suffering from
A) a collapsed trachea.
B) an obstruction in the bronchi.
C) a pneumothorax.
D) decreased surfactant production.
E) a bruised diaphragm.

Answer 79

C) a pneumothorax.

Question 80

In a condition known as pleurisy, there is excess fluid in the pleural space. How would you expect this to affect the process of pulmonary ventilation?
A) Ventilation would require less energy.
B) Breathing would be labored and difficult.
C) It would be easier to expand the lungs on inspiration.
D) More air would be forced out during expiration.
E) Tidal volume would increase.

Answer 80

B) Breathing would be labored and difficult.

Question 81

cessation of breathing

Answer 81

apnea

Question 82

increased respiratory rate and/or volume without increased metabolism

Answer 82

hyperventilation

Question 83

increased respiratory rate and/or volume due to increased metabolism

Answer 83

hyperpnea

Question 84

rapid breathing

Answer 84

tachypnea

Question 85

difficulty breathing

Answer 85

dyspnea

Question 86

Match the change in gas composition with the response (disregard weak responses).

A. PO2 increases.
B. PCO2 increases.
C. PO2 decreases.
D. PCO2 decreases.

Arterioles: systemic constrict, pulmonary dilate.

Answer 86

A. PO2 increases.

Question 87

Match the change in gas composition with the response (disregard weak responses).

A. PO2 increases.
B. PCO2 increases.
C. PO2 decreases.
D. PCO2 decreases.

Bronchioles and systemic arterioles dilate.

Answer 87

B. PCO2 increases.

Question 88

Match the change in gas composition with the response (disregard weak responses).

A. PO2 increases.
B. PCO2 increases.
C. PO2 decreases.
D. PCO2 decreases.

Arterioles: systemic dilate, pulmonary constrict.

Answer 88

C. PO2 decreases.

Question 89

Match the change in gas composition with the response (disregard weak responses).

A. PO2 increases.
B. PCO2 increases.
C. PO2 decreases.
D. PCO2 decreases.

Bronchioles and systemic arterioles constrict.

Answer 89

D. PCO2 decreases.

Question 90

Which single muscle contributes most to normal, resting inspiration? Which single muscle contributes most to normal, resting expiration?

Answer 90

The diaphragm muscle provides most of the force for inspiration. Normal expiration is primarily a result of the diaphragm relaxing, and expiratory muscles do not contribute.

Question 91

Distinguish between cellular and external respiration.

Answer 91

Cellular respiration refers to the intracellular reactions that consume oxygen and produce ATP. External respiration refers to the exchange of gases between the environment and the lungs, lungs and blood, blood and cells, and the transport of those gases.

Question 92

Describe the pleura and explain its role in respiration.

Answer 92

The pleura is a double-walled sac that surrounds each lung. One wall clings to the lung surface, the other to the wall of the thoracic cavity. The pleura secretes and contains pleural fluid, which is a lubricant. Pleural fluid also keeps the wall of the lung in close proximity to the wall of the thoracic cavity, which is critical in the process of pulmonary ventilation.

Question 93

Distinguish between intrapulmonary and intrapleural pressure.

Answer 93

Intrapulmonary pressure is the pressure inside the alveoli. Intrapleural pressure is the pressure within the pleural cavity. Intrapleural pressure variation drives variation inside the alveoli, but is always lower than atmospheric pressure, where pressure inside the alveoli equilibrates with atmospheric pressure during the respiratory cycle.

Question 94

What is surfactant? Why is it important?

Answer 94

Surfactant, made by the type II alveolar cells, reduces the surface tension in the fluid in the alveoli, thereby facilitating inflation and inhibiting collapse of the alveoli.

Question 95

Julia is breathing 14 times per minute, with a tidal volume of 520 mL and a dead space of 152 mL. Lyle is breathing 15 times per minute, with a tidal volume of 400 mL and a dead space of 175 mL. Which patient has better alveolar ventilation?

Answer 95

Alveolar ventilation = ventilation rate × (tidal volume - dead space volume). Julia’s ventilation is 5432 mL/min, which is better than Lyle’s, which is 3375 mL/min.

Question 96

Cindy is taking 14 breaths per minute. Her vital capacity is 3000 mL, her total lung capacity is 4000 mL, and her tidal volume is 450 mL per breath. Calculate the following:
A. Cindy’s total pulmonary ventilation (minute volume)
B. Cindy’s alveolar ventilation rate

Answer 96

A. 14 breaths/min × 450 mL/breath = 6300 mL/min
B. Alveolar vent = 14 breaths/min × (450 mL/ breath - 150 mL dead space)
= 14 breaths/min × 300 mL/breath = 4200 mL/min

Question 97

High carbon dioxide concentration in body fluids is called
A) carbonation.
B) hyperdioxia.
C) hyperoxia.
D) hypercarbia.
E) hypercapnia.

Answer 97

E) hypercapnia.

Question 98

The partial pressure of oxygen in arterial blood is approximately \_\_\_\_\_\_\_\_ mm Hg.
A) 40
B) 45
C) 50
D) 70
E) 100

Answer 98

E) 100

Question 99

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

Answer 99

B) 45

Question 100

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.

Answer 100

A) concentration gradient.

Question 101

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.

Answer 101

C) diffusion.

Question 102

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.

Answer 102

C) pulmonary edema.

Question 103

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.

Answer 103

D) adult respiratory distress syndrome.

Question 104

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.
A) True
B) False

Answer 104

B) False

Question 105

The variables of oxygen consumption, cardiac output, and blood oxygen content are unrelated.
A) True
B) False

Answer 105

B) False

Question 106

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.

Answer 106

C) Each hemoglobin molecule can bind four oxygen molecules.

Question 107

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 107

B) bound to hemoglobin.

Question 108

At a PO2 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

Answer 108

E) over 90

Question 109

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.

Answer 109

A) increased H+ concentration

Question 110

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.

Answer 110

D) increases 2,3-DPG production in blood and can result from anemia.

Question 111

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.

Answer 111

C) bicarbonate ions.

Question 112

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

Answer 112

C) dorsal respiratory group

Question 113

The most important chemical regulator of respiration is
A) oxygen.
B) carbon dioxide.
C) bicarbonate ion.
D) sodium ion.
E) hemoglobin.

Answer 113

B) carbon dioxide.

Question 114

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.

Answer 114

B) increase the rate of breathing.

Question 115

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

Answer 115

B) abdominal and internal intercostal, diaphragm and external intercostal

Question 116

If the neural connections between the pons and medulla are severed, breathing will stop.
A) True
B) False

Answer 116

B) False

Question 117

The Hering-Breuer reflex
A) functions to increase ventilation with changes in blood pressure.
B) alters pulmonary ventilation when the PO2 changes.
C) alters pulmonary ventilation when the PCO2 changes.
D) prevents overexpansion of the lungs.
E) is an important aspect of normal, quiet breathing.

Answer 117

D) prevents overexpansion of the lungs.

Question 118

Protective reflexes of the lungs include
A) coughing.
B) bronchoconstriction.
C) bronchodilation.
D) bronchodilation and coughing.
E) coughing and bronchoconstriction.

Answer 118

E) coughing and bronchoconstriction.

Question 119

destruction of alveoli

Answer 119

emphysema

Question 120

thickened alveolar membrane and decreased lung compliance

Answer 120

fibrotic lung disease

Question 121

decreased surface area for gas exchange

Answer 121

emphysema

Question 122

increased airway resistance

Answer 122

asthma

Question 123

fluid accumulation in interstitial spaces

Answer 123

pulmonary edema

Question 124

increased diffusion distance

Answer 124

pulmonary edema

Question 125

Match the factor with its effect on the affinity of hemoglobin for oxygen.

increased temperature

Answer 125

decrease

Question 126

Match the factor with its effect on the affinity of hemoglobin for oxygen.

increased pH

Answer 126

increase

Question 127

Match the factor with its effect on the affinity of hemoglobin for oxygen.

increased PCO2

Answer 127

decrease

Question 128

Match the factor with its effect on the affinity of hemoglobin for oxygen.

increased 2,3-DPG

Answer 128

decrease

Question 129

Generally, PO2 in arterial blood is ________ than PO2 in venous blood.

Answer 129

higher

Question 130

Generally, PCO2 in arterial blood is ________ than PCO2 in venous blood.

Answer 130

lower

Question 131

PCO2 tends to be ________ in tissues than in systemic capillaries.

Answer 131

higher

Question 132

Diffusion rate is directly proportional to ________ and ________.

Answer 132

surface area, concentration gradient

Question 133

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

Answer 133

Emphysema

Question 134

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

Answer 134

Fibrotic lung disease

Question 135

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

Answer 135

pulmonary edema

Question 136

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

Answer 136

Asthma

Question 137

Diffusion rate is indirectly proportional to ________.

Answer 137

membrane thickness

Question 138

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

Answer 138

dorsal respiratory; ventral respiratory

Question 139

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

Answer 139

dorsal respiratory, diaphragm (or internal intercostal), phrenic (or intercostal)

Question 140

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

Answer 140

mouth and throat (larynx, pharynx, and tongue), obstructive sleep apnea

Question 141

Specialized ________ in the carotid and aortic bodies are activated by a decrease in PO2 and pH or an increase in PCO2. What do they trigger?

Answer 141

glomus cells; they trigger a reflex increase in ventilation.

Question 142

The carotid and aortic bodies contain specialized ________ cells, which can increase ventilation in response to changes in PO2, PCO2, or pH.

Answer 142

glomus

Question 143

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

Answer 143

limbic system

Question 144

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

Answer 144

1. attached to hemoglobin, 23%
2. dissolved, 7%
3. as bicarbonate, 70%

Question 145

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 PO2 in the alveoli
E) All of the answers are correct.

Answer 145

D) decreased PO2 in the alveoli

Question 146

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.

Answer 146

B) increase the partial pressure of oxygen.

Question 147

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 PO2 should be about 70 mm.
D) DPG levels in the red blood cells should be high.
E) All of the answers are correct.

Answer 147

B) the temperature should be slightly lower than normal body temperature.

Question 148

A student in your lab volunteers to enter a hypoxic breathing chamber for 10 minutes, and his alveolar PO2 drops to 50 mm Hg. What other change would occur?
A) decrease in arterial pH
B) decrease in arterial PCO2
C) decrease in pH of cerebrospinal fluid
D) increase in alveolar PCO2
E) hypoventilation

Answer 148

B) decrease in arterial PCO2

Question 149

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.

Answer 149

B) cause an increase in blood pH.

Question 150

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.

Answer 150

D) bicarbonate ions leave the red blood cells.

Question 151

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 PCO2
B) changes in PO2
C) changes in pH due to carbon dioxide levels
D) changes in blood pressure
E) All of the answers are correct.

Answer 151

D) changes in blood pressure

Question 152

What are the two possible causes of lower alveolar PO2? Give examples of each.

Answer 152

1. The composition of the inspired air is abnormal. Altitude affects oxygen content of air.
2. Alveolar ventilation is inadequate. Pathological factors include increased airway resistance (asthma), decreased lung compliance (fibrosis), and overdoses of drugs or alcohol.

Question 153

Describe the problems that result in low arterial oxygen content.

Answer 153

Three categories of problems are inadequacies in oxygen reaching alveoli, oxygen exchange between the alveoli and blood, and transport of oxygen in the blood.

Question 154

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?

Answer 154

Oxygen is not highly soluble in water, which is the main component of plasma. Less than 2% is dissolved in plasma, with the remainder bound to hemoglobin. The iron in the heme portion of the molecule can bind up to four oxygen atoms. Oxygen is not chemically reactive in the body. Carbon dioxide is more soluble than oxygen, at about 7% dissolved. Carbon dioxide is chemically reactive, combining with water to form carbonic acid, which then dissociates to bicarbonate and hydrogen ion. Most carbon dioxide is transported in the form of bicarbonate, about 70%, and the remaining 23% binds to amino acids on hemoglobin.

Question 155

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

Answer 155

Respiratory neurons in the medulla control inspiration and expiration. Neurons in the pons modulate ventilation. The rhythmic pattern of breathing arises from a network of spontaneously discharging neurons. Ventilation is subject to modulation by various chemical factors and by higher brain centers.

Question 156

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

Answer 156

Peripheral chemoreceptors in the carotid and aortic bodies sense changes in oxygen concentration, pH, and PCO2 of the plasma. Central chemoreceptors monitor cerebrospinal fluid composition and respond to changes in the concentration of CO2 in the cerebrospinal fluid.

Question 157

Which is typically more important in regulating the respiratory system, PO2 or PCO2? 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?

Answer 157

PCO2 is the more important factor. For PCO2, there are central and peripheral receptors that respond to CO2 as well as to CO2-related pH. These receptors are very sensitive to routine changes in PCO2 and pH, such as those associated with an increase in physical activity. Peripheral chemoreceptors have been identified for O2, but these respond only to dramatic changes in PO2, such as those associated with high altitude or disease. Because CO2 is produced as a by-product of aerobic (oxygen-consuming) metabolism, an increase in CO2 is associated with a corresponding decrease in O2.