Respiratory Chapter 21 Flashcards
1
Q
1) Which of the following is NOT part of the upper respiratory tract? A) nose B) pharynx C) trachea D) larynx
A
C) trachea
2
Q
2) What is part of the respiratory zone? A) nose B) nasal cavity C) trachea D) alveoli
A
D) alveoli
3
Q
3) The respiratory system does NOT function in: A) acid-base homeostasis. B) odor detection. C) speech production. D) blood cell production.
A
D) blood cell production.
4
Q
4) The process of respiration that moves air into and out of the lungs is: A) gas transport.
B) tissue gas exchange.
C) pulmonary gas exchange.
D) pulmonary ventilation.
A
D) pulmonary ventilation.
5
Q
5) Pulmonary gas exchange occurs in the: A) upper respiratory tract. B) respiratory zone. C) conducting zone. D) larynx.
A
B) respiratory zone.
6
Q
6) Through what openings of the nose does inhaled air enter the upper respiratory tract? A) nasal cavity B) anterior nares C) posterior nares D) nasopharynx
A
B) anterior nares
7
Q
7) What is the advantage of breathing through the nose rather than the mouth?
A) The nose warms, humidifies, and filters inhaled air.
B) The nose provides a more direct route over which air will travel.
C) The nose provides a site for initial gas exchange.
D) The nose is a less turbulent environment than the mouth.
A
A) The nose warms, humidifies, and filters inhaled air.
8
Q
8) What increases air turbulence to extract dust and other debris from air traveling through the nasal cavity? A) nasal conchae and meatuses B) vestibule C) posterior nares D) septal cartilage
A
A) nasal conchae and meatuses
9
Q
9) Which bone lacks a paranasal sinus? A) frontal B) zygomatic C) maxillary D) ethmoid
A
B) zygomatic
10
Q
10) The majority of the nasal cavity is lined with:
A) transitional epithelium.
B) simple squamous epithelium.
C) pseudostratified ciliated columnar epithelium.
D) simple cuboidal epithelium.
A
C) pseudostratified ciliated columnar epithelium.
11
Q
11) What is the function of the goblet cells? A) produce speech B) detect odors C) secrete mucus D) maintain acid-base balance
A
C) secrete mucus
12
Q
2) In what order does air inhaled through the nose travel, from superior to inferior?
A) oropharynx, nasopharynx, laryngopharynx
B) nasopharynx, oropharynx, laryngopharynx
C) laryngopharynx, oropharynx, nasopharynx
D) nasopharynx, laryngopharynx, oropharynx
A
B) nasopharynx, oropharynx, laryngopharynx
13
Q
13) The larynx lining transitions at the vocal cords from stratified squamous nonkeratinized epithelium to:
A) simple squamous epithelium.
B) simple columnar epithelium.
C) pseudostratified ciliated columnar epithelium.
D) transitional epithelium.
A
B) simple columnar epithelium.
14
Q
14) What flap of elastic cartilage keeps food and liquids from entering the larynx during swallowing? A) corniculate cartilage B) epiglottis C) thyroid cartilage D) arytenoid cartilage
A
B) epiglottis
15
Q
15) Upon removal of the larynx, a person would no longer be able to: A) sneeze.
B) swallow.
C) cough.
D) produce sounds.
A
D) produce sounds.
16
Q
16) The mucosa of the carina contains sensory receptors that trigger: A) coughing. B) hiccups. C) yawning. D) sneezing.
A
A) coughing.
17
Q
17) Why are the rings of cartilage surrounding the trachea C-shaped?
A) The C rings of cartilage allow the esophagus to expand during swallowing.
B) The C rings of cartilage allow the trachea to change diameter during breathing.
C) The C rings of cartilage keep the trachea patent (open).
D) The C rings of cartilage allow the esophagus to expand during swallowing, allow the trachea to change diameter during breathing, and keep the trachea patent (open).
A
D) The C rings of cartilage allow the esophagus to expand during swallowing, allow the trachea to change diameter during breathing, and keep the trachea patent (open).
18
Q
18) Which organ's position causes the left lung to be shaped differently from the right lung? A) esophagus B) heart C) liver D) stomach
A
B) heart
19
Q
19) What sweeps foreign debris from the lower respiratory passages? A) gap junctions B) cilia C) microvilli D) flagella
A
B) cilia
20
Q
20) Which of the following correctly describes the histological transition from bronchi into smaller branches in the bronchial tree?
A) The lining changes from respiratory epithelium to stratified squamous epithelium.
B) More hyaline cartilage is found in the smaller passageways of the bronchial tree.
C) The amount of smooth muscle increases in the smaller passageways of the bronchial tree. D) The rings of cartilage completely disappear during the transition from the trachea into the bronchial tree.
A
C) The amount of smooth muscle increases in the smaller
21
Q
21) Air entering the respiratory system travels from the respiratory bronchioles to the: A) terminal bronchioles. B) tertiary bronchi. C) alveolar ducts. D) alveolar sacs.
A
C) alveolar ducts.
22
Q
22) Gas exchange occurs in all of the following EXCEPT: A) alveolar sacs. B) respiratory bronchioles. C) terminal bronchioles. D) alveolar ducts.
A
C) terminal bronchioles.
23
Q
23) What type of alveolar cell produces surfactant? A) alveolar macrophages B) type II alveolar cells C) dust cells D) type I alveolar cells
A
B) type II alveolar cells
24
Q
24) What cells clean and digest debris entering the alveoli? A) type I alveolar cells B) goblet cells C) type II alveolar cells D) alveolar macrophages
A
D) alveolar macrophages
25
25) What does NOT contribute to the formation of the respiratory membrane?
A) type II alveolar cells
B) capillary endothelial cells
C) basal lamina of the type I alveolar cells
D) type I alveolar cells
A) type II alveolar cells
26
```
26) Which epithelium forms the alveoli?
A) simple columnar epithelium
B) simple squamous epithelium
C) stratified squamous epithelium
D) pseudostratified ciliated columnar epithelium
```
B) simple squamous epithelium
27
```
27) The triangular depression in the medial surface of each lung, where blood vessels and the primary bronchi enter, is the:
A) apex.
B) base.
C) hilum.
D) lobule.
```
C) hilum.
28
```
28) Each secondary bronchus supplies air to a:
A) lobule of the lung.
B) bronchopulmonary segment.
C) lobe of the lung.
D) hilum.
```
C) lobe of the lung.
29
```
29) Each lung is situated within a subcavity of the thoracic cavity known as the:
A) peritoneal cavity.
B) pericardial cavity.
C) abdominopelvic cavity.
D) pleural cavity.
```
D) pleural cavity.
30
30) What reduces friction around the lungs as they expand and contract? A) mucus
B) pleural fluid
C) surfactant
D) synovial fluid
B) pleural fluid
31
31) What does Boyle's law state about pressure and volume at a constant temperature and a constant pressure?
A) Pressure increases when volume decreases.
B) Pressure and volume will both increase together or both decrease together.
C) Pressure and volume will both increase as temperature and pressure increase.
D) Pressure and volume will both decrease as temperature and pressure decrease.
A) Pressure increases when volume decreases.
32
32) What part of the following description is INCORRECT? Contraction of the diaphragm and external intercostal muscles leads to increased volume in the thoracic cavity and the lungs. The increase in volume leads to an increase in intrapulmonary pressure causing air to move into the lungs.
A) Increases in volume lead to a decrease in pressure, not an increase in pressure.
B) The contraction of the diaphragm and external intercostal muscles leads to a decrease in volume, not an increase in volume.
C) Increased volume and decreased pressure cause air to leave the lungs, rather than enter the lungs.
D) The relaxation, not contraction, of the diaphragm and external intercostal muscles leads to inhalation.
A) Increases in volume lead to a decrease in pressure, not an increase in pressure.
33
```
33) What happens to the lungs if intrapleural pressure equals or increases above atmospheric pressure?
A) overinflation
B) collapse
C) burst
D) inhalation
```
B) collapse
34
```
34) Predict what happens to air movement when atmospheric pressure is 760 mm Hg, intrapulmonary pressure is 758 mm Hg, and intrapleural pressure is 754 mm Hg.
A) no air movement
B) inhalation
C) exhalation
D) atelectasis
```
B) inhalation
35
```
35) Air moves out of the lungs when the pressure inside the lungs is:
A) less than atmospheric pressure.
B) greater than atmospheric pressure.
C) equal to atmospheric pressure.
D) less than intrapleural pressure.
```
B) greater than atmospheric pressure.
36
```
36) Which of the following is a factor on which expiration depends?
A) recoil of elastic tissue in the lungs
B) decrease in intrapulmonary pressure
C) contraction of expiratory muscles
D) increase in lung volume
```
A) recoil of elastic tissue in the lungs
37
37) What primarily determines airway resistance in the respiratory passageways?
A) elasticity of the lung tissues
B) diameter of the conducting zone passageways
C) presence of surfactant
D) degree of alveolar surface tension
B) diameter of the conducting zone passageways
38
```
38) Which of the following reduces alveolar surface tension?
A) gas
B) water
C) surfactant
D) mucus
```
C) surfactant
39
39) Bronchodilation may occur in response to: A) increased mucus.
B) the parasympathetic nervous system.
C) inflammation.
D) the sympathetic nervous system
D) the sympathetic nervous system
40
```
40) Mr. Schmitzer has pulmonary fibrosis in which the elastic tissue of his lungs is replaced with dense irregular collagenous connective tissue. His condition primarily affects:
A) airway resistance.
B) alveolar surface tension.
C) pulmonary compliance.
D) surfactant production.
```
C) pulmonary compliance.
41
41) Vital capacity =
A) expiratory reserve volume + residual volume
B) inspiratory reserve volume + residual volume
C) tidal volume + inspiratory reserve volume + expiratory reserve volume
D) inspiratory reserve volume + expiratory reserve volume + tidal volume + residual volume
C) tidal volume + inspiratory reserve volume + expiratory reserve volume
42
42) What statement best describes tidal volume?
A) Tidal volume is the air remaining in the lungs after forced expiration. B) Tidal volume is the air exchanged during normal breathing.
C) Tidal volume is the air exhaled after normal inspiration.
D) Tidal volume is the air forcibly expelled after normal expiration.
B) Tidal volume is the air exchanged during normal breathing.
43
43) The volume that remains in the lungs after a forced expiration is the: A) residual volume.
B) dead space volume.
C) vital capacity.
D) functional residual capacity.
A) residual volume.
44
```
44) The amount of air that can be forcibly expired after a normal tidal expiration is known as the:
A) tidal volume.
B) inspiratory reserve volume.
C) expiratory reserve volume.
D) vital capacity.
```
C) expiratory reserve volume.
45
```
45) Which law states that each gas in a mixture exerts its own pressure?
A) Dalton's law
B) Charles' law
C) Boyle's law
D) Henry's law
```
A) Dalton's law
46
```
46) Carbon dioxide has a relatively high solubility in blood plasma although it has a very low partial pressure. What law describes this phenomenon?
A) Dalton's law
B) Boyle's law
C) Henry's law
D) Charles' law
```
C) Henry's law
47
```
47) Which of the following determines the direction of respiratory gas movement?
A) gas solubility in water
B) partial pressure gradient
C) temperature
D) molecular weight of the gas molecule
```
B) partial pressure gradient
48
```
48) The partial pressure of carbon dioxide (PCO2) in the blood of pulmonary capillaries is approximately:
A) 35 mm Hg.
B) 45 mm Hg.
C) 50 mm Hg.
D) 70 mm Hg.
```
B) 45 mm Hg.
49
```
49) The partial pressure of oxygen (PO2) in a pulmonary capillary is about 40 mm Hg. Determine the partial pressure that will promote movement of oxygen into the pulmonary
capillary from air in the alveolus.
A) 18 mm Hg
B) 35 mm Hg
C) 40 mm Hg
D) 104 mm Hg
```
D) 104 mm Hg
50
50) Each of the following factors affects the efficiency of pulmonary gas exchange EXCEPT:
A) diameter of an alveolus.
B) partial pressure of carbon dioxide (PCO2) in the blood of the pulmonary capillaries.
C) thickness of the respiratory membrane.
D) surface area of the respiratory membrane.
A) diameter of an alveolus.
51
```
51) What pulmonary gas exchange problems do you expect to see when surface area is lost due to emphysema?
A) hyperventilation
B) eupnea
C) hypocapnia
D) both hypercapnia and hypoxemia
```
D) both hypercapnia and hypoxemia
52
```
52) The coupling of blood flow with the amount of air reaching the alveoli is known as:
A) ventilation-perfusion matching.
B) partial pressure.
C) Boyle's law.
D) Henry's law.
```
A) ventilation-perfusion matching.
53
53) How is most oxygen transported in the blood?
A) as the bicarbonate ion in the plasma
B) bound to hemoglobin as oxyhemoglobin
C) combined with hemoglobin as carbaminohemoglobin D) as carbonic acid in the plasma
B) bound to hemoglobin as oxyhemoglobin
54
```
54) A fully saturated hemoglobin molecule transports:
A) 1 molecule of oxygen.
B) 2 molecules of oxygen.
C) 4 molecules of oxygen.
D) 8 molecules of oxygen.
```
C) 4 molecules of oxygen.
55
55) The affinity of hemoglobin for oxygen increases with:
A) increased body temperature.
B) increased hydrogen ion concentration.
C) increased partial pressure of carbon dioxide.
D) increased BPG (2, 3-bisphosphoglycerate).
D) increased BPG (2, 3-bisphosphoglycerate).
56
56) What would increase the amount of oxygen unloaded by hemoglobin into peripheral tissues?
A) decreased temperature
B) decreased pH
C) decreased levels of BPG (2, 3-bisphosphoglycerate)
D) decreased levels of PCO2
B) decreased pH
57
```
57) The majority of carbon dioxide is transported:
A) as carbaminohemoglobin.
B) dissolved in plasma.
C) as the bicarbonate ion.
D) as carbonic acid.
```
C) as the bicarbonate ion.
58
```
58) Carbon dioxide and water combine to form:
A) hydrochloric acid.
B) carbonic acid.
C) carbaminohemoglobin.
D) nitric acid.
```
B) carbonic acid.
59
59) What is NOT true of the effects of hypoventilation?
A) carbonic acid concentration in the blood increases
B) blood pH decreases
C) partial pressure of carbon dioxide (PCO2) in the blood increases
D) hydrogen ion concentration in the blood decreases
D) hydrogen ion concentration in the blood decreases
60
```
60) Which of the following counteracts the movement of bicarbonate ions from the RBCs?
A) the Bohr effect
B) Dalton's law
C) the chloride shift
D) ventilation-perfusion matching
```
C) the chloride shift
61
61) Respiratory acidosis results from: A) hyperventilation.
B) hypocapnia.
C) hypoventilation.
D) hypoxia.
C) hypoventilation.
62
```
62) Which of the following is NOT one of the four major processes of respiration?
A) oxygen-hemoglobin dissociation curve
B) pulmonary ventilation
C) pulmonary gas exchange
D) gas transport
```
A) oxygen-hemoglobin dissociation curve
63
63) Which process of respiration relies on partial pressure gradients to move air in and out of the lungs?
A) pulmonary ventilation
B) both pulmonary gas exchange and tissue gas exchange
C) both gas transport and pulmonary ventilation
D) gas transport
A) pulmonary ventilation
64
```
64) Eupnea is controlled by the:
A) apneustic center.
B) glossopharyngeal nerve.
C) respiratory pattern generator (RPG).
D) pneumotaxic center.
```
C) respiratory pattern generator (RPG).
65
65) If the ventral respiratory group (VRG) of neurons was destroyed:
A) tidal volumes would increase.
B) alveolar ventilation would increase.
C) breathing would stop.
D) pulmonary ventilation would increase rapidly.
C) breathing would stop.
66
66) Five-year-old Charlie is so mad that he's holding his breath until he gets his way. What will stimulate his breathing rate to return to normal?
A) accumulation of partial pressure of carbon dioxide (PCO2)
B) lack of oxygen
C) lack of sensory information being sent to central chemoreceptors
D) lack of sensory information being sent to peripheral chemoreceptors
A) accumulation of partial pressure of carbon dioxide (PCO2)
67
67) Considering the role of the chemoreceptor in the regulation of the respiration rate, the most important stimulus that induces changes in ventilation is:
A) partial pressure of oxygen (PO2) in systemic capillaries.
B) partial pressure of carbon dioxide (PCO2) in arterial blood. C) partial pressure of oxygen (PO2) in venous blood.
D) partial pressure of oxygen (PO2) in pulmonary capillaries.
B) partial pressure of carbon dioxide (PCO2) in arterial blood. C) partial pressure of oxygen (PO2) in venous blood.
68
68) Central chemoreceptors monitor:
A) partial pressure of oxygen (PO2) in the blood.
B) hydrogen ion concentration of cerebrospinal fluid (CSF). C) blood pressure.
D) stretch in the walls of the trachea and bronchi.
B) hydrogen ion concentration of cerebrospinal fluid (CSF). C) blood pressure.
69
69) Peripheral chemoreceptors are most sensitive to:
A) partial pressure of oxygen (PO2) in arterial blood.
B) concentration of hydrogen ions in the blood.
C) partial pressure of carbon dioxide (PCO2) in the blood.
D) concentration of hydrogen ions in cerebrospinal fluid.
A) partial pressure of oxygen (PO2) in arterial blood.
70
70) Which of the following triggers hyperventilation?
A) high partial pressure of oxygen (PO2) in arterial blood
B) low partial pressure of carbon dioxide (PCO2) in arterial blood
C) low concentration of hydrogen ions in arterial blood
D) high partial pressure of carbon dioxide (PCO2) in arterial blood
D) high partial pressure of carbon dioxide (PCO2) in arterial blood
71
```
71) What is typical of restrictive lung diseases?
A) decreased efficiency of expiration
B) increased vital capacity
C) decreased pulmonary compliance
D) decreased alveolar surface tension
```
C) decreased pulmonary compliance
72
72) Which of the following accompanies emphysema?
A) alveoli collapse and surface area is lost
B) pulmonary compliance decreases
C) decreased partial pressure of carbon dioxide in the blood D) increase in vital capacity
A) alveoli collapse and surface area is lost
73
73) The upper respiratory tract includes the passageways from the nasal cavity to the larynx.
TRUE
74
74) Air inspired through the nasal cavity will travel through the nasopharynx, oropharynx, and then the laryngopharynx before entering the larynx.
TRUE
75
75) The pharynx is known as the voice box due to the presence of vocal ligaments that vibrate to produce sound.
FALSE
76
76) The last tracheal ring of cartilage, known as the carina, has sensory receptors that can trigger a cough reflex.
TRUE
77
77) Rings of cartilage increase in number while smooth muscle presence decreases as the bronchi branch and become smaller in the conducting zone.
FALSE
78
8) Terminal bronchioles, part of the conducting zone, give rise to respiratory bronchioles, which are part of the respiratory zone.
TRUE
79
79) Most inspired particles, such as dust, fail to reach the lungs because of the ciliated mucous membrane lining the upper respiratory structures.
TRUE
80
80) The lungs are held to the thorax wall by the smooth muscles of the lungs.
FALSE
81
81) The respiratory membrane is a combination of the respiratory bronchioles, alveolar ducts, and alveolar sacs.
FALSE
82
82) Alveolar surface tension determines lung compliance.
TRUE
83
83) Surfactant helps prevent atelectasis by humidifying air before it enters the alveoli.
FALSE
84
84) The partial pressure gradient of oxygen determines the direction of the movement of this respiratory gas.
TRUE
85
85) The bulk of carbon dioxide is carried chemically combined with the amino acids of hemoglobin as carbaminohemoglobin in the RBCs.
FALSE
86
86) Trachea
E
87
87) Diaphragm
G
88
88) Nasal cavity
B
89
89) Pharynx
C
90
90) Larynx
D
91
91) Houses nasal conchae to enhance turbulence for filtering air
F) nasal cavity
92
92) Prevents food and liquid from entering the rest of the respiratory tract
E) larynx
93
93) The smallest airways of the bronchial tree
G) bronchioles
94
94) Simple squamous epithelium creates these air sacs
B) alveoli
95
95) Transports air from the larynx into the lower respiratory tract
C) trachea
96
96) The first branches of the trachea
H) bronchi
97
97) This is the last tracheal cartilage ring
A) carina
98
98) Three regions are the naso-, oro-, and laryngo-
D) pharynx
99
99) Trace the pathway of air into the respiratory system.
Air travels through the nares, nasal cavity, nasopharynx, oropharynx, and laryngopharynx into the larynx, trachea, primary bronchi, secondary bronchi, and tertiary bronchi. Air travels through multiple branches of bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, then into alveolar ducts and alveolar sacs.
100
100) Describe the functional difference between the conducting zone and the respiratory zone of the respiratory tract.
The tubes of the conducting zone transport air into or out of the respiratory system as it is inhaled and exhaled. Air is warmed, filtered, and moistened as it passes through the conducting zone. Gas exchange occurs in the respiratory zone of the alveoli.
101
101) Explain what structures contribute to the function of the nasal cavities.
Air is filtered, warmed, and moistened as it travels through the nasal cavities of the conducting zone of the respiratory system. The paranasal sinuses also warm, humidify, and filter incoming air. Hairs in the vestibule of the nasal cavity prevent particles and insects from entering the nose. Air turbulence is increased by the nasal conchae which help extract debris from inhaled air. Foreign debris sticks to the mucus lining the nasal cavity. Goblet cells in the mucosa of the nasal cavity secrete mucus to trap foreign particles and cilia beat in unison to propel debris toward the posterior nasal cavity where it can be swallowed or expelled by sneezing or blowing one's nose.
102
102) Discuss why pseudostratified ciliated columnar epithelium is an appropriate tissue for the lining of the nasal cavity.
Goblet cells embedded in the mucosa of pseudostratified ciliated columnar epithelium secrete mucus. Foreign particles are trapped in the sticky mucus and propelled to the posterior nasal cavity by cilia present on the apical surface of the epithelium. Contaminated mucus can be swallowed or expelled by sneezing or blowing one's nose.
103
103) Explain why the oropharynx and laryngopharynx are lined with nonkeratinized stratified squamous epithelium rather than pseudostratified ciliated columnar epithelium.
Nonkeratinized stratified squamous epithelium provides better protection than pseudostratified ciliated columnar epithelium since it contains many cell layers. Both the oropharynx and laryngopharynx serve as a passageway for both food and air. The multiple layers prevent abrasion from the passage of food.
104
104) Explain how smoking impairs the protective features of the epithelium of the respiratory tract.
Chemicals in cigarette smoke increase mucus secretion by goblet cells in the epithelium lining the respiratory tract. Those chemicals also paralyze and eventually destroy the cilia responsible for sweeping along contaminated mucus. Although more mucus is available, the natural mechanism for removing it is impaired. A smoker's cough develops as the only way the body can prevent mucus buildup.
105
105) Discuss why the C-shaped rings of cartilage in the submucosa of the trachea are appropriate to their function.
The C-shaped rings of cartilage are rigid enough to provide support to the trachea and keep it open (patent). These rings are also flexible enough to provide for changes in diameter of the trachea. Since the rings do not enclose the posterior surface of the trachea, the esophagus is capable of expanding into the posterior trachea during swallowing.
106
106) Describe how and why the left and right primary bronchi are structurally different from one another.
The right primary bronchus is wider, shorter, and straighter while the left primary bronchus is longer, narrower, and more horizontal. These differences are primary due to the position of the left lung in relation to the heart.
107
107) Document the changes in the histology as the respiratory zone passageways decrease in diameter.
The C-shaped rings of cartilage become complete rings as the bronchi get smaller. These rings become irregular plates and then progressively diminish. The respiratory epithelium changes from respiratory epithelium to columnar cells that gradually become shorter as the bronchi branch and become smaller. Smooth muscle increases in smaller passageways so that the flow of air can be controlled.
108
108) Differentiate terminal bronchioles from respiratory bronchioles.
Terminal bronchioles branch from bronchioles and are the last part of the conducting zone. Each terminal bronchiole gives rise to two or more smaller respiratory bronchioles. Each respiratory bronchiole branches into two or more smaller alveolar ducts, tubes that contain alveoli along their walls. The respiratory bronchioles are the first part of the respiratory zone.
109
109) Explain how changes in volume and pressure lead to pulmonary ventilation.
The contraction of inspiratory muscles promote an increase in the size of the thoracic cavity and thus the volume of the lungs. Intrapulmonary pressure decreases below atmospheric pressure when the volume of the lungs increases. Air moves into the lungs by following along a pressure gradient. As the inspiratory muscles relax and return to their original positions, the volume of the lungs decreases and raises intrapulmonary pressure above atmospheric pressure. Air flows out of the lungs, again following the pressure gradient.
110
110) Differentiate among atmospheric pressure, intrapulmonary pressure, and intrapleural pressure.
Atmospheric pressure is created by gravity pulling on the air surrounding our bodies. Intrapulmonary pressure is the air pressure within the alveoli that changes with inspiration and expiration, but always equalizes with atmospheric pressure. Intrapleural pressure is the pressure within the pleural cavity. It also changes with inspiration and expiration but does not equalize with atmospheric pressure.
111
111) Infants born prematurely do not make enough surfactant to prevent atelectasis. What role does surfactant play in preventing atelectasis? Explain how a lack of surfactant affects pulmonary ventilation.
Surfactant's role is to reduce alveolar surface tension. Without adequate surfactant, alveoli collapse due to the high surface tension of fluid in the alveoli. Pulmonary ventilation then ceases in one or both lungs. It is difficult for alveoli to re-inflate during inspiration to allow for gas exchange to continue.
112
112) Why is the inspiratory reserve volume (IRV) greater than the expiratory reserve volume (ERV)?
The IRV is larger than the ERV by about 1000-1200 mL of air. IRV refers to the volume of air that can be forcibly inspired after a normal tidal inspiration. After a forceful expiration using accessory muscles that can only expel a certain amount of air, is known as the expiratory reserve volume. The ERV is limited because, some air remains in the lungs as a volume known as the residual volume (RV). The RV is due mostly to the intrapleural pressure and outward recoil of the chest wall, which keeps the lungs slightly inflated and limits the amount of air that can be expelled. Therefore the IRV is larger than the ERV.
113
113) The partial pressure gradient for oxygen in the body is much steeper than that for carbon dioxide. Explain how equal amounts of these two gases can be exchanged (in a given time interval) in the lungs and at the tissues. What law describes this phenomenon?
Equal amounts of oxygen and carbon dioxide can be exchanged in the lungs and at the tissues because carbon dioxide is 20 times more soluble in water than oxygen. Henry's law states that the degree to which a gas dissolves in a liquid is proportional to both its partial pressure and its solubility in the liquid.
114
114) What is the chloride shift and why does it occur?
The chloride shift is an exchange of negatively charged ions. Negatively charged chloride ions move from the plasma into the erythrocytes to counterbalance the movement of negatively charged bicarbonate ions into the plasma. Bicarbonate ions formed inside erythrocytes from carbon dioxide move into the plasma for transport.
115
115) Julisa won a lottery ticket and began to hyperventilate in her excitement. Explain how hyperventilation affects the partial pressure of carbon dioxide in her blood and her blood pH.
Hyperventilation is the increase in the rate and/or depth of Julisa's breathing. She expires more carbon dioxide, thus lowering the partial pressure of carbon dioxide in her blood and raising her blood pH. This could lead to respiratory alkalosis.
116
116) Sherell has damaged her phrenic nerve after diving head-first into a shallow lake. Predict the effect on her pattern of ventilation.
The phrenic nerve supplies the diaphragm with nerve impulses that promote inspiration. Without a viable connection to the ventral respiratory group (VRG) in the medulla, the rate of ventilation cannot be controlled. Sherell's diaphragm may not contract when needed and the rate of pulmonary ventilation will decrease.
117
117) Explain how restrictive disease patterns differ from obstructive disease patterns.
Restrictive diseases decrease pulmonary compliance and reduce the effectiveness of inspiration. Restrictive diseases decrease the inspiratory capacity, vital capacity, and total lung capacity, and make effective pulmonary ventilation more difficult. Obstructive diseases increase airway resistance. Obstructive diseases decrease the efficiency of expiration since the elastic recoil of the lungs after expiration can collapse the airways.
118
118) A man eating in a restaurant chokes on a piece of food. He grabs his neck, unable to speak. Why is it significant that the man cannot talk? Where has the food lodged?
The inability to speak indicates that the man is choking on a piece of food that suddenly closed off air at or below the glottis, the opening to the larynx. Sound is created as air moves past the vocal ligaments of the larynx.
119
119) Which respiratory-associated muscles would contract when you take a deep breath to blow up a balloon? Explain the role of these muscles in pulmonary ventilation.
For a forced or deep inspiration needed to blow up a balloon, the diaphragm and external intercostal muscles contract forcefully to increase the height and diameter of the thoracic cavity, and thus the volume of the lungs. Accessory muscles such as the muscles of the back, neck, and chest will also contract to further increase the size of the thoracic cavity. The increase in lung volume decreases pressure in the alveoli and causes a pressure gradient along which air moves into the lungs.
120
120) Mr. Carroll's broken rib pierced through his right lung causing air to enter the intrapleural space. What will happen to his lung, intrapleural pressure, and intrapulmonary pressure?
Air in the intrapleural space is known as pneumothorax. If intrapleural pressure increases to a level at or above atmospheric pressure, the intrapleural pressure can no longer exert a suction effect that prevents the lungs from collapsing. The added intrapleural pressure enhances the lungs' elastic recoil and the lungs collapse.
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121) Ms. Trejo uses a bronchodilator, a medication that helps her breathe easier during an asthma attack. Explain the impact this medication will have on pulmonary ventilation.
The degree of airway resistance is largely determined by the diameter of the bronchiole passageways. The bronchodilator medication Ms. Trejo takes will decrease airway resistance by dilating the bronchiole passageways. Relaxation of smooth muscle in the bronchioles increases the size of the bronchiole's lumen (opening). This will better allow the passage of air in and out of the lungs and make it easier to breathe.
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122) What is hypercapnia and how does it affect respiration?
Hypercapnia refers to high levels of carbon dioxide in the blood. The rise in carbon dioxide levels is detected by central chemoreceptors (in the medullary reticular formation) and peripheral chemoreceptors (in the carotid and aortic bodies) and stimulates the DRG. The DRG relays information to the VRG, which triggers an increase in the rate and depth of ventilation.
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123) An angry child holds his breath since his parents said it is time to come in from playing. His carbon dioxide levels continue to climb and his parents are concerned what will happen to him. Predict how the respiratory system handles the rising carbon dioxide levels.
As carbon dioxide levels increase, the pH of the blood decreases becoming more acidic. High arterial PCO2 detected by central chemoreceptors stimulates the ventral respiratory
group (VRG) to trigger an increase in the rate of ventilation. The VRG stimulates the inspiratory muscles to contract and increase the breathing rate. Hyperventilation removes excess carbon dioxide from the blood and leads to a decrease in PCO2.
