Respiratory Physiology Flashcards
(130 cards)
1
Q
what is respiration
A
all components of the interchange of gases between the atmosphere and cells
2
Q
what is ventilation
A
movement of air into and out of the lungs, alveoli
3
Q
what is gas exchange
A
diffusion between air in lungs and blood; diffusion between blood and tissues
4
Q
upper respiratory tract
A
nose, nasal cavity, pharynx larynx
5
Q
lower respiratory tract
A
trachea, bronchi, lungs
6
Q
the junction of bronchi is called
A
carina
7
Q
the carina contains
A
irritant receptors that trigger the cough reflex
8
Q
the conducting zone
A
trachea to terminal bronchioles
9
Q
the respiratory zone
A
respiratory bronchioles to alveoli
10
Q
tidal volume
A
volume of air inhaled in one breath
11
Q
inspiratory reserve volume
A
volume between normal inhalation and maximal inhalation
12
Q
expiratory reserve volume
A
volume between normal passive exhalation and maximal exhalation
13
Q
residual volume
A
volume of air after maximal exhalation
14
Q
inspiratory capacity
A
tidal + inspiratory reserve
15
Q
vital capacity
A
tidal + inspiratory reserve + expiratory reserve
16
Q
total lung capacity
A
total lung volume (including residual capacity)
17
Q
minute ventilation (VE)
A
total volume of air breathed per minute; TVxf
18
Q
clusters of alveoli are surrounded by (2)
A
elastic fibres and a capillary network
19
Q
Type I vs Type II pneumocytes
A
Type I: gas exchange; 95% of surface
Type II: surfactant
20
Q
larger alveoli have (more/less) surface tension
A
less
21
Q
surfactant consists of
A
lipids and proteins
22
Q
what is the role of surfactant
A
equalize PRESSURE between different alveoli
23
Q
what contracts to allow inspiration
A
external intercostals, diaphragm (also serratus dorsalis cranialis)
24
Q
quiet expiration is a result of
A
elastic recoil of the lungs and ribcage
25
active expiration is a result of
elastic recoil + internal intercostal muscles, rectus abdominis, external/internal oblique and transversus abdominis
26
elastic recoil of the lung is due to
elastic tissue, surface tension in alveoli
27
what is compliance
distensibility of the lungs (ease with which lungs and thorax expand)
28
conditions that decrease compliance
pulmonary fibrosis, pulmonary edema, respiratory distress syndrome
29
T/F pleural space is normally a virtual space
T
30
describe Ppl during breathing
subatmospheric at rest (-); becomes more - during inspiration, becomes less - (sometimes +) during expiration
31
if lung compliance decreases, ppl becomes more ____ on inhalation
negative (can damage the lung)
32
if airway resistance increases, ppl becomes more ______ on inspiration (especially with ____ airway obstruction), and more _______ on expiration (especially with ______ airway obstruction)
negative; upper; positive; lower
33
dead space
all ventilated parts of the respiratory system where gas exchange does not occur
34
T/F the conducting pathways are dead space
T
35
anatomic dead space + alveolar dead space =
physiologic dead space
36
if dead space ventilation increases, what often happens to alveolar ventilation
decreases
37
T/F you want to maximize dead space
F
38
________ flow tends to occur in larger airways whereas ______ flow tends to occur in smaller airways
turbulent; laminar
39
if turbulent flow develops in smaller airways, total gas movement is ______________ and lung sounds ___________
decreased; increase
40
T/F there is more resistance in the upper airways than the lower airways
T
41
histamine, leukotrienes, serotonin and TXA2 all promote (constriction/dilation) of airways
constriction
42
nitric oxide promotes (constriction/dilation) of airways
dilation
43
sympathetic receptors in the airways are primarily
β2 -> SM relaxation
44
common causes of inspiratory dyspnea
stenotic nares, dorsal displacement of soft palate, brachycephalic syndrome, laryngeal hemiplegia
45
common causes of expiratory dyspnea
physical narrowing of intrathoracic airways (ex. bronchoconstriction, edema), collapse of intrathoracic airways, pleural effusion, pneumothorax
46
T/F vascular pressures are lower in the pulmonary circulation than in the systemic circulation
T
47
T/F vessel walls of the pulmonary circulation are thicker walled and contain more smooth muscle than segments in the systemic circulation
F: other way around
48
T/F the lungs act as a blood reservoir during low demand
T
49
bronchial arteries are _________; bronchiolar arteries and alveolar duct arteries are called
elastic; muscular
50
the bulk of gas exchange occurs
between inflation and deflation (decrease in pressure therefore blood rushes in)
51
most resistance to pulmonary blood flow is in
arterioles
52
pulmonary vascular pressure differences during cardiac and respiratory cycles are due in part to changes in
pulmonary vascular resistance
53
what are the passive influences of PVR and PVP
cardiac pressure, pulmonary inflation, capillary distension and recruitment, hematocrit, vascular anatomy and position
54
during exhalation, extra-alveolar arterioles/venules are _____________, but alveolar capillaries are _________(septa are _____)
compressed; dilated; not stretched
55
during inhalation, extra-alveolar arterioles/venules are _____________, but alveolar capillaries are _____________(septa are ______)
dilated; compressed; stretched tight
56
increased perfusion pressure results in what changed to pulmonary capillaries, which _______ PVR
increased distension and recruitment, which decreases PVR
57
as blood viscosity increases, PVR __________
increases
58
the ________ portion of the lung is preferentially perfused due to _______ resistance
dorsal; lower
59
what are the active influences of PVP and PVR
neural/hormonal factors, oxygen tension
60
most prostaglandins cause (vasoconstriction or vasodilation)
vasodilation
61
a decrease in oxygen concentration in a pulmonary arteriole causes (vasoconstriction or vasodilation)
vasodilation
62
what is the significance of bronchopulmonary anastamoses
provide collateral circulation to keep alveoli alive in the event that a bronchi or a vessel becomes occluded
63
T/F one of the factors that draws H2O back into capillaries is the HP of capillaries
F; surrounded by air therefore only capillary oncotic pressure works to bring H2O back in
64
oxygen comprises what % of the molecules in air
21%
65
in dry air, PO2 =
PB x FO2 (barometric pressure x fraction of oxygen, 21%)
66
T/F PO2 of inspired air is lower than the environmental PO2 because air is humidified
T (gets diluted by water vapour)
67
T/F to keep PACO2 constant, alveolar ventilation increases when CO2 production lowers
F; it increases when CO2 production increases (ex. during exercise)
68
T/F alveolar oxygen tension is lower than that of inspired air because oxygen is continuously diffusing out of the alveoli and into the blood
T
69
the respiratory exchange ratio (rate of CO2 production/rate of O2 consumption) is typically what value
0.8
70
O2 moves because of ________________ whereas CO2 moves because
large concentration gradient between PAO2 and PaO2; it is readily diffusible
71
T/F CO2 is 20x more effective at diffusion than O2
T
72
Diffusion depends on
1. relative diffusion coefficient of gas (D)
2. surface area for diffusion (A)
3. distance between air and blood (X)
4. pressure gradient
73
what happens to gas exchange in the lung during exercise
get higher cardiac output, so the velocity of blood flow is high; diffusion equilibrium does not occur in alveoli (less efficient) BUT is happening more frequently, so more O2 is overall delivered to tissues
74
what happens to gas exchange in tissues during exercise
blood vessels dilate -> blood flow slows -> more time for gas exchange; the distance the gas has to travel is also reduced
75
In normal, healthy animals, the V/Q ratio is
~0.8
76
what is a cause of normal, small V/Q mismach
gravity: some areas have lower V/Q than others
77
what happens to V/Q when the alveolus is supplied by an obstructed bronchiole
drops low
78
how to fix a low V/Q ratio due to airway obstruction
increase O2 administration
79
T/F V/Q mismatch due to a right-to-left shunt responds well to O2 therapy
F
80
what happens to V/Q when the alveolus is ventilated but has no blood? would this respond well to O2 therapy
becomes almost infinite; NO (because there is no blood to deliver any O2)
81
what happens to V/Q when there is a left-to-right-shunt
drops to 0
82
Hg structure
2α and 2β subunits surrounding a heme (C/N lattice with iron in the middle)
83
Hg can bind up to how many O2 at a time
4
84
Hg transports what % of O2 in blood
98
85
porphyria
a mutation in any of 8 genes that leads to a buildup of porphyrins in the body (heme is usually made from porphyrins and iron)
86
as heme enters lung and picks up oxygen, what happens
its affinity for O2 increases and it starts to pick it up more rapidly
87
as heme enters tissue and releases oxygen what happens
its affinity for O2 decreases and release becomes more rapid
88
hg is most fully saturated at what oxygen tension
70-80 mmHg
89
as temperature rises, Hg affinity for O2
falls
90
as pH decreases, Hg affinity for O2
decreases
91
as DPG levels rise, Hg affinity for O2
decreases
92
as Hg is depleted of O2, it changes colour to; this is called
reddish-blue; cyanosis
93
what can cause cyanosis (2)
reduced O2 uptake; reduced blood flow
94
oxy-Hb absorbs more (red or infrared) in pulse oximetry
infrared light
95
deoxy-hb absorbs more (red or infrared) in pulse oximetry
red
96
active tissues produce CO2, carbonic acid, and lactic acid, lowering pH and facilitating the release of O2 from Hg via what effect
Bohr effect
97
how does O2 delivery increase during exercise (3)
1. 5-fold increase in CO
2. 50% increase in Hb due to splenic contraction
3. marked increase in the O2 gradient between capillaries and tissue
98
CO poisoning produces what colour in mucous membranes and skin
cherry red
99
what is the Haldane effect
deoxygenated blood has increased affinity for CO2
100
most CO2 is carried in the blood as
HCO3 (via carbonic anhydrase)
101
T/F CO2 rides on Hg bound to the heme
F; bound to the globin
102
fetal adaptations to low O2 includes (3)
higher Hb affinity for O2; higher Hb; higher CO
103
describe fetal Hb
2α and 2γ
104
control of ventilation come from centers in the
cerebrum, brainstem and spinal cord
104
T/F fetal hemoglobin affinity for oxygen is greater than adult hemoglobin
T
105
what monitors changes in blood gas tensions and pH
peripheral and central chemoreceptors
106
T/F multiple inputs regulate the rhythm of breathing
T
107
breathing is adjusted to
activity level, metabolism, posture, and non-respiratory behaviours (sniffling, vocalizing, eating)
108
what are SARs and what is their role
Slowly Adapting Stretch Receptors; sense increase in airway volume and terminate the inspiration
109
sustained stimulation of SARs causes
activation of expiratory neurons -> active breathing
110
what innervates SARs
vagus (parasympathetic)
111
irritant receptors are innervated by
vagus
112
activation of irritant receptors triggers
bronchoconstriction, increased mucous production, coughing
113
where are J receptors (C-fiber receptors) and what is their role
in pulmonary interstitium near capillaries; monitor the blood composition and interstitial volume and alter RR
114
what is responsible for increasing RR when interstitial pressure rises during infectious, allergic or vascular disease
J receptors (C-fiber receptors)
115
what is the job of sensory input from skeletal muscles
monitor force of muscle contraction and inhibit if too great
116
what is the job of chemoreceptors in the carotid and aortic bodies
sense changes in PaO2 and PaCO2, pH and change the rate and depth of breathing
117
where is the carotid body located
bifurcation of carotid arteries
118
T/F carotid bodies are the only structures monitoring PaO2 in adults
T
119
what are the biggest stimuli for the carotid bodies to trigger an AP and significant increases in ventilation
small drop in pH or increase in PaCO2
120
what are the central chemoreceptors
located in the medulla (pons and ventricles) and respond to changes in CO2 by sensing the drop in pH
121
T/F stimulation of pain receptors increases RR and depth
T
122
large particles tend to deposit where in the respiratory tract
in the nasopharynx - impaction
123
medium particles tend to deposit where in the respiratory tract
small airways - sedimentation
124
small particles tend to deposit where in the respiratory tract
alveoli - diffusion
125
what are the sources of mucous for the respiratory tract
goblet cells (in larger airways); submucosal bronchial glands (in the bronchi); Clara cells (in respiratory bronchioles)
126
secretion of mucous in the respiratory tract is under what regulation
autonomic
127
changes in the sol layer alter ________________ whereas changes in the gel layer alter _________________
ciliary function; clearance rates
128
T/F the lungs can uptake/convert/degrade hormones/chemicals/toxins in the mixed venous blood
T
129
macrophages, bradykinin, histamine, serotonin, PGE2, PGF2, heparin are all released by the pulmonary tissue/cells into
systemic blood
