Deck 12: The Respiratory System

Question 1

Without pulmonary surfactant, which one of these actions would happen

A)Small alveoli would tend to collapse.
B)Larger alveoli would tend to empty into smaller alveoli.
C)All alveoli would become easier to inflate.
D)The surface tension in the alveoli would become reduced.

Answer 1

A

Question 2

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

A)The size of the thoracic cavity reduces.
B)The intra-alveolar pressure becomes greater than the atmospheric pressure.
C)Air flows out of the lungs.
D)The expiratory muscles contract.

Answer 2

D

Question 3

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

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

Answer 3

B

Question 4

Which of these statements does NOT refer to alveoli

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

Question 5

Which of the following does NOT hold the lungs against the thoracic wall

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

Question 6

Which of the following is NOT a function of the respiratory system

A)to transport O₂ to the tissues
B)to contribute to maintenance of normal acid-base balance
C)to provide a route for heat and water elimination
D)to enable speech, singing, and other vocalization

Question 7

Which of these actions 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 8

Which are the muscles that control inhalation

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

Question 9

Which of the following does NOT contribute to keeping the alveoli open

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

Question 10

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
D)elastic fibres in the bronchiole

Question 11

Which statement describes 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 12

What does pulmonary compliance refer to specifically

A)the effort required to stretch the lungs
B)the elasticity of the lung tissue
C)the energy requirements for an inspiration
D)the surface area of the alveoli

Question 13

Which of these statements does NOT describe pulmonary surfactant

A)It is secreted by Type II alveolar cells.
B)It is deficient in newborn respiratory distress syndrome.
C)It 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 14

Which of these skeletal muscles is innervated by the phrenic nerve

A)rectus abdominis
B)diaphragm
C)external intercostal
D)sternocleidomastoid

Question 15

Which of these statements does NOT describe 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.
D)It is a lipoprotein.

Question 16

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

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

Question 17

Which activity below is NOT a respiratory event

A)Carbon dioxide is exchanged in the alveoli.
B)Gas exchange occurs between tissues and the blood.
C)Cells produce nitrogen by their metabolism.
D)Oxygen is exchanged in the alveoli.

Question 18

Which of these factors will NOT make breathing more difficult

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

Question 19

Which of these statements describes 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 20

Which of the following 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)Intra-alveolar pressure increases.
D)Intrathoracic pressure decreases.

Question 21

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 22

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 23

Which of the following 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 24

Which of these statements describes 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 25

If the pulmonary ventilation rate is 3200 mL/minute, and tidal volume is 400, what is the respiratory rate per minute

A)2.8 breaths per minute
B)8 breaths per minute
C)12.5 breaths per minute
D)16 breaths per minute

Question 26

Which of these factors would result in bronchoconstriction

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

Question 27

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

A)3500 mL/minute
B)3920 mL/minute
C)5450 mL/minute
D)7700 mL/minute

Question 28

Which of the following does NOT bring about increased airway resistance

A)asthma
B)epinephrine and norepinephrine
C)slow-reactive substance of anaphylaxis
D)emphysema

Question 29

Which of these conditions occurs 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 30

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 31

Which of the following does NOT happen during forceful expirations

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

Question 32

What happens when intra-alveolar pressure becomes greater than atmospheric pressure

A)Air flows out of the lungs.
B)Air flows into the lungs.
C)There is no air flow.
D)The lung collapses.

Question 33

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

A)forced inspiration
B)passive expiration
C)forced expiration
D)pneumothorax

Question 34

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 35

Which of the following does NOT happen during inspiration

A)Intra-alveolar pressure falls below atmospheric pressure.
B)The diaphragm contracts.
C)The internal intercostal muscles contract.
D)The volume of the thoracic cavity increases.

Question 36

Which one of these 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

Question 37

Which one of these factors would reduce the alveolar ventilation rate the most

A)increased alveolar dead space
B)decreased alveolar dead space
C)increased tidal volume
D)increased vital capacity

Question 38

Which one of these circumstances causes intrapleural pressure to exceed airway pressure

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

Question 39

Which of these statements describes functional residual capacity

A)the extra volume of air that can be actively expired
B)the minimum volume of air remaining in the lungs even after a maximal expiration
C)the volume of air in the lungs at the end of a normal passive respiration
D)the volume of air entering or leaving the lungs during a single breath

Question 40

Which of these statements describes vital capacity

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

Question 41

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 42

Which one of these factors would decrease the diffusion of a gas across the alveolar/pulmonary capillary membrane

A)an increase in the thickness of the membrane
B)an increase in the surface area of the membrane
C)an increase in the partial pressure gradient
D)the gas's smaller molecular size

Question 43

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 mmHg

Question 44

Which of these conditions would result in the lowest alveolar ventilation rate

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

Question 45

Which of the following does NOT make breathing more difficult

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

Question 46

Which of these statements does NOT describe 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.
D)It is highest in the pulmonary vein.

Question 47

If 20 percent of the air is composed of O₂, what is the partial pressure of oxygen at an altitude of 20000 feet, where atmospheric pressure is 350 mmHg

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

Question 48

Which of these statements does NOT describe 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 red blood cells.

Question 49

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

A)20 mmHg
B)46 mmHg
C)100 mmHg
D)760 mmHg

Question 50

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

Question 51

In which of these ways is carbon dioxide NOT transported in the blood

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

Question 52

Which of these factors would reduce the amount of oxygen transferred 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 53

Which of these statements does NOT apply to haemoglobin

A)It 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)It combines only with O₂.
C)It is found in erythrocytes.
D)It is an iron-bearing, protein molecule.

Question 54

Which of these statements does NOT describe the partial pressure of oxygen in the pulmonary veins

A)It is about 100 mmHg.
B)It is equivalent to alveolar partial pressure.
C)It is the same as pulmonary arteries' partial pressure.
D)It is highest in pulmonary veins.

Question 55

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 56

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

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

Question 57

Which of these statements applies to the percent of haemoglobin saturation

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

Question 58

Which of these statements does NOT describe the plateau portion of the O₂-Hb curve

A)It is within 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 within the blood PO₂ range that exists at the systemic capillaries.
D)It is the range that exists at the pulmonary capillaries.

Question 59

Which of these factors 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 60

What is the atmospheric PO₂

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

Question 61

Which of these statements does NOT describe hypercapnia

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

Question 62

Which of these statements describes the apneustic centre

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 63

Which of these statements describes 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.
D)They are often inactive.

Question 64

Which of these statements describes expiratory neurons

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

Question 65

Which of these statements describes haemoglobin

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.
D)It combines preferentially with CO₂ when the partial pressure of O₂ is high in arterial blood.

Question 66

Which of these statements does NOT describe carbonic anhydrase

A)It is found in 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.
D)It accelerates the reaction of carbon dioxide and water.

Question 67

What is the location of the receptors that are stimulated by a large drop in the blood PO₂ level

A)respiratory centre of the brain
B)arterioles
C)tissue capillaries
D)carotid and aortic bodies

Question 68

Which of these statements does NOT indicate why a chloride shift occurs in red blood cells

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

Question 69

Which of these statements does NOT describe haemoglobin

A)Its presence keeps the blood PO₂ low and favours O₂ movement into the blood.
B)It can combine with O₂, CO₂, H⁺, and CO.
C)It unloads less O₂ in the presence of increased tissue acidity.
D)It unloads more O₂ when body temperature is higher.

Question 70

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

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

Question 71

Which one of these situations occurs if the oxygen-haemoglobin dissociation curve is shifted to the right

A)Partial pressure of oxygen is increased.
B)pH is decreased.
C)Temperature is decreased.
D)Partial pressure of carbon dioxide is decreased.

Question 72

Which of these statements does NOT describe 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.
D)It affects the degree of binding of oxygen to haemoglobin.

Question 73

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

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

Question 74

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

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

Question 75

Which of these statements does NOT describe the peripheral chemoreceptors

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 76

Which of these statements describes the dorsal respiratory group (DRG)

A)It consists of both inspiratory neurons and expiratory neurons.
B)Its neurons remain inactive during normal quiet breathing.
C)It is called into play by the VRG when the demand for ventilation is increased.
D)Inspiration takes place when its inspiratory neurons fire.

Question 77

Which one of these conditions exists at high altitudes

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

Question 78

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 79

For which of these gases does haemoglobin have the greatest affinity

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

Question 80

What does it mean to say that haemoglobin is fully saturated

A)There is an oxygen molecule attached to each of the four heme groups.
B)Oxygen is attached to both the heme and the globin portions of the molecule.
C)Red blood cells contain as many haemoglobin molecules as possible.
D)Haemoglobin is carrying both oxygen and carbon dioxide simultaneously.