Deck 12: The Respiratory System

Question 1

The intrapulmonary pressure

A) is the pressure within the air sacs of the lung.
B) always equilibrates with atmospheric pressure.
C) is always less than intrapleural pressure.
D) both (a) and (b) above.
E) all of these answers.

Answer 1

both (a) and (b) above.

Question 2

Which of the following is not a function of the respiratory system?

A) transports O2 to the tissues
B) contributes to maintenance of normal acid-base balance
C) provides a route for heat and water elimination
D) enables speech, singing, and other vocalization
E) removes, modifies, activates, or inactivates various materials passing through the pulmonary circulation

Answer 2

transports O2 to the tissues

Question 3

In addition to gas exchange the respiratory system plays a key role in

A) enhancing venous return.
B) water and temperature balance.
C) body defense.
D) both (a) and (c) above.
E) all of these answers.

Answer 3

all of these answers.

Question 4

Type I alveolar cells

A) form the wall of the alveoli.
B) secrete pulmonary surfactant.
C) contract during expiration to force air out of the alveoli.
D) two of these answers.
E) all of these answers.

Question 5

Inspiratory events occur because

A) the air pressure in the alveoli is greater than that of the atmosphere.
B) the air pressure in the alveoli is less than that of the atmosphere.
C) the volume of the thoracic cavity increases.
D) both (a) and (c) above.
E) both (b) and (c) above

Question 6

Which of the following structures serves as a common passageway for both the respiratory and digestive systems?

A) nose
B) pharynx
C) trachea
D) bronchi
E) esophagus

Question 7

During which of the following would the intrapleural pressure be greater than atmospheric pressure?

A) forced inspiration.
B) passive expiration.
C) forced expiration.
D) pneumothorax.
E) none of these answers.

Question 8

Which of the following pressure (mm Hg) would be recorded as intrapleural pressure during a normal resting expiration?

A) 752
B) 756
C) 760
D) 764
E) 0

Question 9

The entire sequence of events involved in the exchange of O? and CO? between the body cells and the environment is known as

A) internal respiration.
B) external respiration.
C) ventilation.
D) breathing.
E) both ventilation and breathing are correct.

Question 10

At the end of a normal expiration when outward air flow has ceased,

A) intra-alveolar pressure is less than atmospheric pressure.
B) intra-alveolar pressure is greater than atmospheric pressure.
C) intra-alveolar pressure is equal to atmospheric pressure.
D) intrapleural pressure is greater than atmospheric pressure.
E) intrapleural pressure is greater than intra-alveolar pressure.

Question 11

A transmural pressure gradient exists across the lung wall because the ____ pressure is less than the ____ pressure.

A) intrapleural, intra-alveolar.
B) intra-alveolar, intrapleural.
C) intrapleural, atmospheric.
D) atmospheric, intra-alveolar.
E) none of these answers.

Question 12

Airway resistance

A) is normally the primary factor determining the amount of flow into/out of the lungs.
B) is increased when the diameter of the airways becomes reduced.
C) when elevated requires an increased pressure gradient between the lungs and atmosphere through vigorous respiratory efforts to move even normal volumes of air into and out of the lungs.
D) both (b) and (c) above.
E) all of these answers.

Question 13

During inspiration,

A) intra-alveolar pressure falls below atmospheric pressure.
B) the diaphragm contracts.
C) the internal intercostal muscles contract.
D) both (a) and (b) above.
E) all of these answers.

Question 14

Which activity below is not a respiratory event?

A) carbon dioxide is exchanged in the alveoli.
B) cells produce nitrogen by their metabolism.
C) gas exchange between tissues and the blood.
D) oxygen is exchanged in the alveoli.
E) pulmonary ventilation.

Question 15

Which of the following pressure (mm Hg) would be recorded as intra-alveolar pressure during a normal resting inspiration?

A) 756
B) 760
C) 764
D) 768
E) 0

Question 16

When intra-alveolar pressure becomes greater than atmospheric pressure,

A) air will flow out of the lungs.
B) air will flow into the lungs.
C) there will be no air flow.
D) both (a) and (b) above.
E) none of these answers.

Question 17

The inspiratory muscles include the

A) diaphragm and internal intercostal muscles.
B) diaphragm and external intercostal muscles.
C) diaphragm and abdominal muscles.
D) internal and external intercostal muscles.
E) none of these answers.

Question 18

The lungs contain:

A) mostly smooth muscle
B) only cartilage
C) no elastic tissue
D) about 500 million alveoli
E) none of the above

Question 19

Which of the following is the last step that produces an inspiration?

A) the atmospheric pressure becomes lower than the intrapleural pressure.
B) the diaphragm contracts.
C) the intercostal muscles contract.
D) the intra-alveolar pressure becomes lower than the atmospheric pressure.
E) the intrapleural pressure becomes positive.

Question 20

The lungs are held against the thoracic wall due to

A) the negative intrapleural pressure.
B) the positive intrapulmonary pressure.
C) cohesiveness of the pleural fluids.
D) both (a) and (c) above.
E) all of these answers.

Question 21

Which factor would result in bronchoconstriction?

A) sympathetic stimulation.
B) secretion of acetylcholine
C) epinephrine secretion.
D) increased carbon dioxide concentration.
E) none of these answers.

Question 22

When blood flow to an area of the lungs is reduced but the area receives normal air flow all of the following occur except

A) the concentration of CO₂ in this area will be decreased.
B) the change in CO₂ concentration will cause the smooth muscles of the local airways to relax.
C) the change in CO₂ concentration will lead to increased resistance of local airways.
D) the change in O₂ concentration will lead to dilation of local blood vessels.
E) the change in O₂ concentration will lead to decreased vascular resistance.

Question 23

When the level of blood flow is not ideally matched with the amount of airflow in a localized area of lung tissue

A) autoregulatory mechanisms are invoked.
B) the autonomic nervous system couples the events more ideally.
C) if airflow is low and blood flow to high, arteriolar vasoconstriction occurs.
D) both (a) and (b) above.
E) both (a) and (c) above.

Question 24

Which of the following does not occur during expiration when a person is breathing quietly?

A) the size of the thoracic cavity is reduced.
B) the intra-alveolar pressure becomes greater than atmospheric pressure.
C) air flows out of the lungs.
D) the expiratory muscles contract.
E) intrapleural pressure is less than intra-alveolar pressure.

Question 25

The residual volume

A) helps prevent lung collapse.
B) is the normal volume of air inhaled.
C) is the normal volume of air exhaled.
D) is the maximum volume of air that can be inspired.
E) is the minimum volume of air that can be inspired.

Question 26

Which skeletal muscle serves as an accessory respiratory muscle?

A) rectus abdominus.
B) diaphragm.
C) external intercostal.
D) internal intercostal.
E) none of the above

Question 27

Pulmonary surfactant

A) is secreted by Type II alveolar cells.
B) decreases surface tension of the fluid lining the alveoli.
C) resists elastic recoil of the lungs.
D) is a combination of lipoproteins.
E) all of these answers.

Question 28

Normal expirations are brought on by

A) contraction of the external intercostals.
B) contraction of the internal intercostals.
C) contraction of the diaphragm.
D) elastic recoil of inspiratory muscles.
E) elastic recoil of expiratory muscles.

Question 29

The work of breathing normally requires about 3% of total energy expenditure, this increases under all of the following situations except

A) when elastic recoil is decreased.
B) when resistance goes up.
C) when the partial pressure of oxygen decreases in the air.
D) when ventilation must be increased.
E) it increases with all of the above

Question 30

Which of the following statements concerning pulmonary surfactant is incorrect?

A) pulmonary surfactant is secreted by Type II alveolar cells.
B) pulmonary surfactant is deficient in newborn respiratory distress syndrome.
C) pulmonary surfactant promotes elastic recoil of the lungs.
D) the cohesive force between a water molecule and an adjacent pulmonary surfactant molecule is much lower than the cohesive force between two adjacent water molecules.
E) pulmonary surfactant reduces surface tension.

Question 31

Which of the following events occurs during expiration?

A) diaphragm moves upward
B) thoracic volume increases
C) external intercostal muscles contract
D) ribs are elevated
E) phrenic nerve is inactive

Question 32

The minimum volume of air that remains in the lungs after a maximal expiration is termed the

A) tidal volume.
B) functional residual capacity.
C) residual volume.
D) vital capacity.
E) no air remains in the lungs after maximal expiration.

Question 33

COPD:

A) affects inspiration to a greater degree than expiration
B) forces small airways to stay open during expiration
C) is the same as apnea
D) increases airway resistance
E) makes inspiration easier

Question 34

Bronchodilation of the air passages involves the ____ of their smooth muscle contraction and the ____ of their radius.

A) decrease, decrease.
B) decrease, increase.
C) increase, decrease.
D) increase, increase.

Question 35

During forceful expirations

A) the accessory expiratory muscles contract.
B) the internal intercostals contract.
C) the abdominal muscles contract.
D) the ribs are brought closer together.
E) all of these answers.

Question 36

Which of the following promotes elastic recoil of the lungs?

A) elastic fibers in the lung.
B) surface tension of the fluid lining the alveoli.
C) pulmonary surfactant.
D) both (a) and (b) above.
E) all of these answers.

Question 37

Which of the following does not bring about increased airway resistance?

A) asthma.
B) epinephrine.
C) slow-reactive substance of anaphylaxis.
D) emphysema.
E) excess mucus production.

Question 38

Which of the following makes breathing more difficult?

A) increased pulmonary compliance.
B) increased airway resistance.
C) decreased elastic recoil.
D) both (a) and (b) above.
E) both (b) and (c) above.

Question 39

When the diaphragm contracts

A) the volume of the thoracic cavity increases.
B) lung volume increases as the lungs are forced to expand.
C) the intra-alveolar pressure increases.
D) both (a) and (b) above.
E) all of these answers.

Question 40

Without pulmonary surfactant,

A) small alveoli would tend to collapse.
B) larger alveoli would tend to empty into smaller alveoli.
C) all alveoli would be easier to inflate.
D) the surface tension in the alveoli would be reduced.
E) inspirations would be easier.

Question 41

If the pulmonary ventilation rate is 3200 ml/minute with a tidal volume of 400, the respiratory rate is ____ breaths per minute.

A) 6
B) 8
C) 14
D) 16
E) 20

Question 42

Compliance refers specifically to the

A) effort required to stretch the lungs.
B) elasticity of the lung tissue.
C) energy requirements for an inspiration.
D) surface area of the alveoli.
E) volume of air moved per breathing cycle.

Question 43

PO? in the blood

A) refers to the pressure exerted by the amount of oxygen dissolved in the blood.
B) is the most important factor determining the percent saturation of hemoglobin.
C) is normal in carbon monoxide poisoning.
D) two of these answers.
E) all of these answers.

Question 44

Systemic venous PO₂ is ____ alveolar PO₂ , and systemic venous PCO₂ is ____ alveolar PCO₂ .

A) greater than, greater than.
B) greater than, less than.
C) less than, greater than.
D) less than, less than.
E) equal to, equal to.

Question 45

If 20% of the air is composed of O₂, the partial pressure of oxygen at sea level where atmospheric pressure is 760 mm Hg is

A) 20 mm Hg.
B) 760 mm Hg.
C) 70 mm Hg.
D) 350 mm Hg.
E) 152 mm Hg.

Question 46

A person who has a tidal volume of 400 ml/breath, a respiratory rate of 14 breaths/minute, and an anatomic dead space volume of 120 ml will have a pulmonary ventilation rate of

A) 3000 ml/minute.
B) 3920 ml/minute.
C) 4260 ml/minute.
D) 5600 ml/minute.
E) 6240 ml/minute.

Question 47

Which of the following spirometry results would not be expected of a patient suffering from obstructive lung disease?

A) normal total lung capacity
B) increased functional residual capacity
C) decreased residual volume
D) decreased FEV1
E) decreased functional residual capacity

Question 48

A person who has a tidal volume of 400 ml, a respiratory rate of 14 and an anatomic dead space volume of 150 ml will have an alveolar ventilation rate of

A) 3,500 ml/minute.
B) 3,920 ml/minute.
C) 4,260 ml/minute.
D) 5,600 ml/minute.
E) 6,240 ml/minute.

Question 49

Which factor would reduce the alveolar ventilation rate the most?

A) increased alveolar dead space.
B) decreased alveolar dead space.
C) increased respiratory rate.
D) increased tidal volume.
E) quiet breathing.

Question 50

Which condition would result in the highest alveolar ventilation rate?

A) quiet breathing.
B) a normal respiratory rate and normal tidal volume.
C) a normal respiratory rate and high tidal volume.
D) a high respiratory rate and very low tidal volume.
E) a low respiratory rate and very low tidal volume.

Question 51

Which of the following would decrease diffusion of a gas across the alveolar/pulmonary capillary membrane?

A) an increase in thickness of the membrane
B) an increase in surface area of the membrane
C) an increase in the partial pressure gradient
D) two of these answers.
E) all of these answers.

Question 52

Which type of chronic obstructive pulmonary disease is characterized by inflammation from smoking cigarettes?

A) asthma
B) chronic bronchitis
C) emphysema
D) two of these answers.
E) all of these answers.

Question 53

The tidal volume:

A) is the volume normally entering or leaving the lungs during a single breath.
B) is the maximum volume that can be moved in or out during a single breath.
C) is the maximum volume the lungs can hold.
D) is the minimum volume the lungs can hold.
E) none of these answers.

Question 54

The partial pressure of oxygen in the pulmonary veins

A) is about 100 mmHg.
B) equivalent to alveolar partial pressure.
C) is dramatically different than pulmonary arteries' partial pressure
D) both (a) and (b) above.
E) all of these answers.

Question 55

Which of the following forces does not contribute to keeping the alveoli open?

A) alveolar surface tension
B) transmural pressure gradient
C) pulmonary surfactant
D) alveolar interdependence
E) none of these answers.

Question 56

Which factor below would reduce the amount of oxygen transfer across the respiratory membrane?

A) a higher partial pressure of oxygen in the atmosphere.
B) an abnormally high partial pressure of carbon dioxide in the atmosphere.
C) a reduced partial pressure of carbon dioxide in the atmosphere.
D) a low pulmonary capillary, partial pressure of oxygen.
E) none of these answers.

Question 57

You are on an airplane at an altitude of 20,000 feet where atmospheric pressure is 350 mm Hg. Air is pumped into the cabin for you to breath. What would the percent of oxygen in this are need to be to allow you to breath air with a partial pressure of oxygen of around the normal 150 mm Hg?

A) 10%
B) 20%
C) 40%
D) 100%
E) 150%

Question 58

Which of the following circumstances might cause small airways to collapse?

A) during normal quiet breathing
B) during maximal forced expiration
C) during pneumothorax
D) both (b) and (c) above.
E) all of these answers.

Question 59

If the alveolar PO? is 100 mm Hg, the blood leaving the pulmonary capillaries in a normal person will have a PO? of

A) 40 mm Hg.
B) 46 mm Hg.
C) 100 mm Hg.
D) 760 mm Hg.
E) none of these answers.

Question 60

The partial pressure of oxygen in the

A) atmospheric air averages 79% of total atmospheric pressure.
B) blood is the most important factor that determines the extent to which O₂ will combine with hemoglobin.
C) arterial blood is decreased when hemoglobin preferentially combines with CO rather than O₂.
D) both (a) and (b) above.
E) all of these answers.

Question 61

The brain region that provides output to the respiratory muscles is located in the

A) pons.
B) medulla.
C) cerebral cortex.
D) cerebellum.
E) hypothalamus.

Question 62

Carbonic anhydrase

A) is found in the red blood cells.
B) catalyzes the formation of carbonic acid from carbonic dioxide and water.
C) catalyzes the formation of oxyhemoglobin from oxygen and reduced hemoglobin.
D) both (a) and (b) above.
E) both (a) and (c) above.

Question 63

2,3-diphosphoglycerate

A) is produced within red blood cells.
B) production is inhibited by HbO₂ .
C) concentration gradually increases whenever Hb in the arterial blood is chronically undersaturated.
D) both (a) and (b) above.
E) all of these answers.

Question 64

Which conditions exists at high altitudes?

A) histotoxic hypoxia.
B) hypoxic hypoxia.
C) anemic hypoxia.
D) hypocapnia.
E) none of these answers.

Question 65

Hemoglobin

A) combines preferentially with O₂ over any other substance.
B) when combined with carbon dioxide is known as carboxyhemoglobin.
C) plays a critical role in determining the amount of O₂ that is exchanged between alveoli and blood, because it acts as a storage depot, removing dissolved O₂ from the blood thereby keeping PO₂ low and allowing net diffusion of O₂ to continue until the hemoglobin is completely saturated.
D) both (a) and (b) above.
E) all of these answers

Question 66

The atmospheric PO₂ is approximately

A) 25 mmHg.
B) 120 mmHg.
C) 160 mmHg.
D) 220 mmHg.
E) the same as for nitrogen.

Question 67

Which of the following statements concerning hemoglobin is correct?

A) the presence of hemoglobin keeps the blood PO₂ low and favors O₂ movement into the blood despite a very large transfer of O₂ until hemoglobin is completely saturated.
B) hemoglobin can combine with O₂, CO₂, H⁺, and CO.
C) hemoglobin unloads more O₂ in the presence of increased tissue acidity.
D) hemoglobin buffers against changes in pH due to respiratory carbonic acid.
E) all of these answers.

Question 68

The amount of oxygen unloaded from hemoglobin at the tissue level increases when

A) PCO₂ in the tissue increases.
B) the concentration of DPG in the red blood cells increases.
C) the concentration of DPG in the red blood cells decreases.
D) both (a) and (b) above.
E) both (a) and (c) above.

Question 69

Hemoglobin

A) plays a critical role in determining the total amount of O₂ that is exchanged because it acts as a storage depot, removing dissolved O₂ and thus keeping the PO₂ low so that net diffusion is allowed to continue.
B) combines only with O₂ .
C) is found in erythrocytes.
D) both (a) and (c) above.
E) all of these answers.

Question 70

Which ion exchanged with bicarbonate by the RBC?

A) Na⁺
B) K⁺
C) Cl^-
D) both Na⁺ and K⁺
E) calcium

Question 71

Which gas is converted to bicarbonate as part of its transport within the blood?

A) oxygen
B) carbon monoxide
C) carbon dioxide
D) nitrogen
E) both (b) and (c)

Question 72

Hemoglobin has the greatest affinity for

A) carbon dioxide.
B) oxygen.
C) carbon monoxide.
D) nitrogen.
E) sulfur dioxide.

Question 73

Select the incorrect statement about hemoglobin.

A) It combines with oxygen at the lungs.
B) It contains iron.
C) It forms an irreversible association with oxygen.
D) It is located inside the red blood cell.
E) Its globin portion is a polypeptide.

Question 74

Hypercapnia

A) refers to excess CO₂ in the arterial blood.
B) occurs when CO₂ is blown off to the atmosphere at a rate faster than it is being produced by the tissues.
C) may be caused by hypoventilation.
D) both (a) and (b) above.
E) both (a) and (c) above.

Question 75

Carbon dioxide is transported in the blood in all the following ways except

A) bicarbonate ion.
B) carbonic acid.
C) directly dissolved.
D) as a gas.
E) as carbaminohemoglobin.

Question 76

The percent of hemoglobin saturation

A) decreases as PO₂ increases.
B) decreases as PCO₂ increases.
C) decreases as H⁺ decreases.
D) decreases as body temperature decreases.
E) none of these answers.

Question 77

Which of the following enhance oxygen release from Hb?

A) a small partial pressure gradient for oxygen between blood and tissue
B) an increase in temperature.
C) an decrease in PCO₂.
D) an decrease in acidity.
E) an decrease in DPG.

Question 78

The plateau portion of the O₂ -Hb curve

A) is in the blood-PO₂ range that exists at the pulmonary capillaries.
B) means that hemoglobin becomes almost nearly saturated in the lungs unless the pulmonary capillary PO₂ falls below 60 mm Hg.
C) is in the blood-PO₂ range that exists at the systemic capillaries.
D) both (a) and (b) above.
E) both (b) and (c) above.

Question 79

Approximately what percentage of oxygen is transported in the blood bound to Hb?

A) 1.5
B) 15
C) 60
D) 98.5
E) 100

Question 80

Approximately what percent of carbon dioxide is transported in the blood dissolved in dissolved form?

A) 1.5
B) 10
C) 35
D) 60
E) 100