Deck 11: The Respiratory System

Question 1

What are the muscles for inhalation?

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

Answer 1

B

Question 2

What is the respiratory quotient?

A) the rate at which gases diffuse across the alveolar capillary membrane
B) the respiratory rate times the tidal volume
C) the ratio of O2 consumed to CO2 produced
D) the ratio of CO2 produced to O2 consumed

Answer 2

D

Question 3

What is the term for the entire sequence of events involved in the exchange of O₂ and CO₂ between the body cells and the environment?

A) internal respiration
B) external respiration
C) ventilation
D) diffusion

Answer 3

B

Question 4

Which statement is correct for the intrapulmonary pressure?

A) It is the pressure within the air sacs of the lung.
B) It is always greater than atmospheric pressure.
C) It is always less than intrapleural pressure.
D) It is the pressure within the bronchi.

Question 5

What does NOT happen/s during forceful expirations?

A) The accessory expiratory muscles contract.
B) The external intercostals contract.
C) The abdominal muscles contract.

Question 6

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 occurs between tissues and the blood.
D) Oxygen is exchanged in the alveoli.

Question 7

Which statement is NOT true as to why inspiratory events occur?

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.

Question 8

Which structure serves as a common passageway for both the respiratory and digestive systems?

A) Nose
B) Pharynx
C) Trachea
D) Esophagus

Question 9

Which statement concerning alveoli is INCORRECT?

A) Alveoli are the site of gas exchange in the lungs.
B) Interdependence of alveoli refers to air flow between adjacent alveoli through the pores of Kohn.
C) Alveolar Type II cells secrete pulmonary surfactant.
D) Alveoli are very thin and are surrounded by a network of capillaries so that air and blood are separated by a very thin barrier.

Question 10

What does NOT happen during inspiration?

A) Intra-alveolar pressure falls below atmospheric pressure.
B) The diaphragm contracts.
C) The internal intercostal muscles contract.

Question 11

Which statement is correct when outward airflow has ceased at the end of a normal expiration?

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.

Question 12

What does NOT happen 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.

Question 13

Which statement is correct for Type I alveolar cells?

A) They form the wall of the alveoli.
B) They secrete pulmonary surfactant.
C) They contract during expiration to force air out of the alveoli.
D) They are responsible for surface tension

Question 14

What 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.

Question 15

What brings on normal expirations?

A) contraction of the external intercostals
B) contraction of the internal intercostals
C) contraction of the diaphragm
D) elastic recoil of stretched lung tissues and relaxation of inspiratory muscles

Question 16

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

Question 17

What happens 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) The lung collapses.

Question 18

Which of the following does NOT make breathing more difficult?

A) increased pulmonary compliance
B) increased airway resistance
C) decreased elastic recoil

Question 19

What does not hold the lungs against the thoracic wall?

A) the negative intrapleural pressure
B) the negative intrapulmonary pressure
C) cohesiveness of the pleural fluids

Question 20

What is NOT a function of the respiratory system?

A) transporting O2 to the tissues
B) contributing to maintenance of normal acid-base balance.
C) providing a route for heat and water elimination.
D) enabling speech, singing, and other vocalization.

Question 21

Which factor would result in bronchoconstriction?

A) sympathetic stimulation
B) parasympathetic stimulation
C) epinephrine secretion
D) increased carbon dioxide concentration

Question 22

Which spirometry result 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

Question 23

Which statement is correct for the vital capacity?

A) It is the volume normally entering or leaving the lungs during a single breath.
B) It is the maximum volume that can be moved in or out during a single breath.
C) It is the maximum volume the lungs can hold.
D) It is the minimum volume the lungs can hold.

Question 24

Which skeletal muscle is innervated by the phrenic nerve?

A) rectus abdominus
B) Diaphragm
C) external intercostal
D) Sternocleodomastoid

Question 25

Which type of chronic obstructive pulmonary disease is characterized by a breakdown of alveolar walls and collapse of the smaller airways?

A) Asthma
B) chronic bronchitis
C) Emphysema
D) bronchiectasis

Question 26

What does compliance refer to specifically?

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

Question 27

Without pulmonary surfactant,what would happen?

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.

Question 28

Which statement 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.

Question 29

What is the term for the minimum volume of air that remains in the lungs after a maximal expiration?

A) tidal volume
B) functional residual capacity
C) residual volume
D) vital capacity

Question 30

A person has a tidal volume of 400 mL/breath,a respiratory rate of 14 breaths/minute,and an anatomic dead space volume of 120 mL.What is her pulmonary ventilation rate?

A) 3000 mL/minute.
B) 3920 mL/minute.
C) 4260 mL/minute.
D) 5600 mL/minute.

Question 31

What does NOT bring about increased airway resistance?

A) Asthma
B) epinephrine and norepinephrine
C) slow-reactive substance of anaphylaxis
D) Emphysema

Question 32

Which of the following does NOT promote elastic recoil of the lungs?

A) elastic fibres in the lung
B) surface tension of the fluid lining the alveoli
C) pulmonary surfactant

Question 33

Which circumstance causes intrapleural pressure to exceed airway pressure?

A) normal quiet breathing
B) maximal forced expiration
C) pneumothorax
D) pleural effusion

Question 34

The work of breathing normally requires about 3 percent of total energy expenditure.In which situation will this decrease NOT occur?

A) when elastic recoil is decreased
B) when resistance goes up
C) when the partial pressure of oxygen increases in the air
D) when ventilation is increased

Question 35

Which statement is correct for residual volume?

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

Question 36

What does NOT occur when blood flow to an area of the lungs is reduced but the area receives normal air flow?

A) The concentration of CO2 in this area decreases.
B) The change in CO2 concentration causes the smooth muscles of the local airways to relax.
C) The change in CO2 concentration leads to increased resistance of local airways.
D) The change in O2 concentration leads to dilation of local blood vessels.

Question 37

Which force does NOT contribute to keeping the alveoli open?

A) alveolar surface tension
B) transmural pressure gradient
C) pulmonary surfactant
D) alveolar interdependence

Question 38

What 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.

Question 39

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 40

Which of the following statements is NOT true for pulmonary surfactant?

A) It is secreted by Type I alveolar cells.
B) It decreases surface tension of the fluid lining the alveoli.
C) It resists elastic recoil of the lungs.

Question 41

If the alveolar PO₂ is 100 mmHg,what will be the PO₂ of the blood leaving the pulmonary capillaries in a normal person?

A) 40 mmHg
B) 46 mmHg
C) 100 mmHg
D) 760 mmHg

Question 42

Which factor 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

Question 43

Which of the following is NOT true for PO₂ in the blood?

A) It refers to the pressure exerted by the amount of oxygen in the atmosphere.
B) It is the most important factor determining the percent saturation of haemoglobin.
C) It is normal in carbon monoxide poisoning.

Question 44

Which of the following is NOT true for the plateau portion of the O₂-Hb curve?

A) It is in the blood-PO2 range that exists at the pulmonary capillaries.
B) It means that haemoglobin becomes almost nearly saturated in the lungs unless the pulmonary capillary PO2 falls below 60 mmHg.
C) It is in the blood-PO2 range that exists at the systemic capillaries.

Question 45

A person has a tidal volume of 400 mL,a respiratory rate of 14,and an anatomic dead space volume of 150 mL.What is his alveolar ventilation rate?

A) 3,500 mL/minute
B) 3,920 mL/minute
C) 4,260 mL/minute
D) 5,600 mL/minute

Question 46

Which factor would reduce the alveolar ventilation rate the most?

A) increased alveolar dead space
B) decreased alveolar dead space
C) increased tidal volume
D) quiet breathing

Question 47

If 20 percent of the air is composed of O₂,what is the partial pressure of oxygen at sea level where atmospheric pressure is 760 mmHg?

A) 20 mmHg
B) 70 mmHg
C) 152 mmHg
D) 760 Hg

Question 48

Which statement is NOT true of the partial pressure of oxygen in the pulmonary veins?

A) is about 40 mmHg.
B) is equivalent to alveolar partial pressure.
C) is the same as pulmonary arteries' partial pressure.

Question 49

Approximately what percentage of oxygen is transported in the blood dissolved in free form?

A) 1.5
B) 15
C) 60
D) 72

Question 50

What is the atmospheric PO₂?

A) approximately 25 mmHg
B) approximately 120 mmHg
C) approximately 160 mmHg
D) approximately 220 mmHg

Question 51

If the pulmonary ventilation rate is 3200 mL/minute with a tidal volume of 400,what is the respiratory rate per minute?

A) 6 breaths
B) 8 breaths
C) 14 breaths
D) 16 breaths

Question 52

Which condition would result in the lowest alveolar ventilation rate?

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

Question 53

What will NOT result in lower oxygen saturation of haemoglobin?

A) an increase in PO2
B) an increase in temperature
C) an increase in PCO2
D) an increase in acidity

Question 54

If 20 percentof the air is composed of O₂,what is the partial pressure of oxygen at an altitude of 20,000 feet where atmospheric pressure is 350 mmHg?

A) 20 mmHg
B) 70 mmHg
C) 152 mmHg
D) 760 Hg

Question 55

Systemic venous PO₂ is _____ alveolar PO₂,and systemic venous PO₂ is _____ alveolar PO₂.

A) greater than, greater than
B) greater than, less than
C) less than, greater than
D) less than, less than

Question 56

Which statement is NOT true for haemoglobin?

A) Haemoglobin 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) Haemoglobin combines only with O2.
C) Haemoglobin is found in erythrocytes.

Question 57

Which statement regarding the percent of haemoglobin saturation is correct?

A) It decreases as PO2 increases.
B) It decreases as PCO2 increases.
C) It decreases as H+ decreases.
D) It decreases as body temperature decreases.

Question 58

What 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) smaller molecular size

Question 59

For what does haemoglobin have the greatest affinity?

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

Question 60

Which of the following is TRUE about the partial pressure of oxygen?

A) Atmospheric air averages 79 percent of total atmospheric pressure.
B) Blood is the most important factor that determines the extent to which O2 will combine with haemoglobin.
C) Arterial blood is decreased when haemoglobin preferentially combines with CO rather than O2.
D) Arterial blood is increased in high atmospheric pressure.

Question 61

Which statement is NOT true for carbonic anhydrase?

A) It is found in the red blood cells.
B) It catalyzes the formation of carbonic acid from carbonic dioxide and water.
C) It catalyzes the formation of oxyhaemoglobin from oxygen and reduced haemoglobin.

Question 62

What condition exists at high altitudes?

A) histotoxic hypoxia
B) hypoxic hypoxia
C) anemic hypoxia
D) hypocapnia

Question 63

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

A) 1.5 percent
B) 10 percent
C) 35 percent
D) 60 percent

Question 64

What is the primary regulator of the magnitude of ventilation in normal circumstances?

A) H+ concentration of the brain extracellular fluid, which is monitored by central chemoreceptors
B) PO2 of the arterial blood, which is monitored by central chemoreceptors
C) PO2 of the arterial blood, which is monitored by peripheral chemoreceptors
D) PCO2 of arterial blood, which is monitored by central chemoreceptors

Question 65

Which statement is correct for expiratory neurons?

A) They are found in both the DRG and VRG.
B) They send impulses to the expiratory muscles during normal quiet breathing.
C) They are stimulated by the pneumotaxic centre.
D) They are stimulated by the inspiratory neurons and in turn inhibit the inspiratory neurons.

Question 66

Which statement is the INCORRECT statement about haemoglobin?

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.

Question 67

Where does pacemaker activity that establishes the rhythmicity of breathing reside?

A) lung tissue
B) respiratory muscles
C) dorsal respiratory group
D) phrenic nerve

Question 68

In which way is carbon dioxide NOT transported in the blood?

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

Question 69

Which statement concerning the peripheral chemoreceptors is INCORRECT?

A) They are stimulated whenever the arterial PO2 falls below normal.
B) They are weakly stimulated by a rise in arterial PCO2.
C) They are stimulated by an increase in arterial H+, which plays an important role in acid-base balance.
D) They are located at the bifurcation of the common carotid arteries and in the aortic arch.

Question 70

What is the location of the brain region that provides output to the respiratory muscles?

A) pons
B) medulla
C) cerebral cortex
D) hypothalamus

Question 71

Which statement is NOT true for 2,3-bisphosphoglycerate?

A) It is produced within red blood cells.
B) Its production is inhibited by HbO2.
C) Its concentration gradually decreases whenever Hb in the arterial blood is chronically undersaturated.

Question 72

Which statement concerning haemoglobin is INCORRECT?

A) The presence of haemoglobin keeps the blood PO2 low and favours O2 movement into the blood despite a very large transfer of O2 until haemoglobin is completely saturated.
B) Haemoglobin can combine with O2, CO2, H+, and CO.
C) Haemoglobin unloads less O2 in the presence of increased tissue acidity.

Question 73

Which statement regarding the apneustic centre is correct?

A) It is located in the medulla.
B) It stimulates the inspiratory neurons.
C) It inhibits inspiratory activity.
D) It is located in the midbrain.

Question 74

Which statement concerning the dorsal respiratory group (DRG)is correct?

A) The DRG consists of both inspiratory neurons and expiratory neurons.
B) The neurons of the DRG remain inactive during normal quiet breathing.
C) The DRG is called into play by the VRG as when demands for ventilation are increased.
D) Inspiration takes place when DRG inspiratory neurons fire.

Question 75

Which of the following is TRUE regarding inspiratory neurons?

A) They activate the phrenic nerve, bringing about contraction of the diaphragm
B) They are stimulated by stretch receptors
C) They are inhibited by the expiratory neurons

Question 76

Which statement is NOT true for hypercapnia?

A) It refers to excess CO2 in the arterial blood.
B) It occurs when CO2 is blown off to the atmosphere at a rate faster than it is being produced by the tissues.
C) It may be caused by hypoventilation.

Question 77

What is the primary form in which CO₂ is transported in the blood?

A) physically dissolved
B) bound to haemoglobin
C) bound to plasma protein
D) as bicarbonate

Question 78

Where are the stretch receptors for the Hering-Breuer reflex located?

A) midbrain
B) elastic tissue of the lungs
C) medulla
D) smooth muscle layer of the airways

Question 79

Which statement is NOT true when the chloride shift in red blood cells occurs?

A) to prevent electrical gradient development.
B) in response to bicarbonate movement into the plasma.
C) to prevent an increase in blood pH.

Question 80

Which statement regarding haemoglobin is correct?

A) It combines preferentially with O2 over any other molecules.
B) When combined with carbon dioxide, it is known as oxyhaemoglobin.
C) It 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 and thereby keeping PO2 low and allowing net diffusion of O2 to continue until the haemoglobin is completely saturated.
D) It combines preferentially with CO2 when partial partial pressure of O2 is high in arterial blood.