Respiratory Flashcards
1
Q
what is the average minute volume
A
5 L of air per minute
2
Q
what is the transpulmonary pressure (Ptp)
A
difference in pressure between the inside and outside of the lung = alveolar pressure - intrapleural pressure
3
Q
what is intrapleural pressure (Pip)
A
pressure in the pleural space aka intrathoracic pressure
4
Q
what is the alveolar pressure (Palv)
A
air pressure in pulmonary alveoli
5
Q
what initiates inspiration
A
neurally induced contraction of diaphragm and ext intercostal muscles
6
Q
how do ext intercostal muscles increase thoracic volume
A
activation of motor neurons cause contraction = upwards and outwards movement of ribs
7
Q
what occurs as the thorax expands
A
- intrapleural pressure lowers
- transpulmonary pressure becomes more positive
- results in lung expansion as Ptp is becoming greater than elastic recoil exerted by lungs
8
Q
why does air enter the lungs in inspiration
A
alveolar pressure becomes negative = inward airflow
9
Q
at the end of inspiration why is there no airflow
A
alveolar pressure = atmospheric pressure
10
Q
what initiates expiration
A
motor neurones to diaphragm and ext intercostal muscles stop firing = relax
11
Q
why do the lungs passively collapse
A
relaxation causes intrapleural pressure to increase
+ decrease transpulmonary pressure = elastic recoil stronger so lungs collapse
12
Q
how is air expelled from alveoli
A
reducing lungs = alveoli compressed = increase alveolar pressure = exceeds atmospheric pressure so air flows outward
13
Q
what type of process is expiration at rest
A
passive
14
Q
what is required during exercise
A
forced expiration
15
Q
what occurs in forced expiration
A
- internal intercostals + abdo muscles also contract = increase intra-abdominal pressure
- ribs move down and in = force diaphragm further into thorax = decrease thoracic volume
16
Q
what provides the greatest airways resistance
A
trachea bc smallest surface area
17
Q
what is dead space
A
volume of air not contributing to ventilation = 175mls in total
18
Q
what is the total combined area for gas exchange
A
40-100m squared
19
Q
what are the 7 layers for gas exchange
A
- alveolar tissue
- tissue interstitium
- capillary endothelium
- plasma layer
- red cell membrane
- red cell cytoplasm
- Hb binding
20
Q
what is ventilation-perfusion matching
A
to be most efficient = proportion of alveolar airflow and capillary blood flow to an area of the lung should be equal
21
Q
what is the effect of V-P mismatch
A
pO2 will decrease and pCO2 will increase in systemic-arterial blood because not enough ventilation for perfusion
22
Q
why is naturally some V-P mismatch
A
gravitational effects = increase filling of blood vessels at bottom of lung
23
Q
what is hypoxic vasoconstriction
A
blood is diverted to better ventilated parts of the lung = unique to pulmonary vessels
24
Q
what are 2 responses to V-P mismatch
A
hypoxic vasoconstriction and local bronchoconstriction
25
where does the control of breathing come from
medulla oblongata
26
what do the neurons of the dorsal respiratory group do
1. fire during inspiration
2. lead to contraction of inspiratory muscles
3. lungs fill at constant rate
4. end of inspiration = rapid decrease in excitation of inspiratory muscles
27
where is the respiratory rhythm generator located
in the pre-Botzinger complex of neurons in the upper part of the ventral respiratory group
28
what is the respiratory rhythm generator
pacemaker cells/neural network that set the basal respiratory rate
29
what is found in the pons
pneumotaxic centre
| apneustic centre
30
what is the role of the pneumotaxic centre
inhibits apneustic centre
promotes expiration
can switch off inspiratory neurons to prevent hyperinflation
31
what is the role of the apneustic centre
stimulates the dorsal respiratory group
| increases intensity of inhalation
32
what do the neurons of the ventral respiratory group do
1. stimulated by DRG
2. involved in inspiration and expiration
3. stimulate accessory muscles of expiration
33
what do the mechano/chemoreceptors in the larynx do
inhibit central controller - medullary respiratory centre
34
what do the receptors in the pharynx do
receptors activated by swallowing to stop respiratory activity and protect against aspiration
35
name 3 myelinated pulmonary receptors
slowly adapting stretch (SASR)
rapidly adapting stretch (RASR)
irritant
36
name a non-myelinated pulmonary receptor
C fibres J receptors
37
what are SASR's
1. activated by lung distension
2. high activity inhibits further inspiration = begin expiration
3. if inflation maintained then slowly adapt to low frequency firing
38
what are RASR's
1. activated by lung distention
2. produce brief burst of activity at onset of stimulus
3. high activity causes bronchoconstriction
39
where are C fibres J receptors found
in capillary walls/interstitium
40
where are SASR's found
in airway smooth muscle
41
where are RASR's found
between airway epithelial cells
42
what are C fibres J receptors
1. stimulated by increase in interstitial fluid
| 2. results in rapid, shallow breathing/bronchoconstriction
43
when might C fibres J receptors be stimulated
during vascular congestion = occlusion of pulmonary vessel/left ventricular heart failure/strenuous activity
44
what is the effect of neural input from j receptors
gives rise to sensations of pressure in chest = feels like breathing is difficult
45
where are the peripheral chemoreceptors found
bifurcation of common carotid arteries and arch of aorta = carotid bodies and aortic bodies
46
what are peripheral chemoreceptors stimulated by
decrease pO2 and increase H+ conc
47
where are type 2 cells found and what do they do
located on carotid sinus
| release stored neurotransmitters on detection of hypoxia = stimulate carotid sinus nerve
48
what is the predominant peripheral chemoreceptor involved in control of respiration
carotid body input
49
when do peripheral chemoreceptors fire
only when pO2 is below 90%
50
what are the 3 effects of peripheral chemoreceptor stimulation
1. increase resp rate and tidal volume
2. direct blood flow towards kidneys and brain
3. increase CO to maintain blood flow
51
where are the central chemoreceptors located
in the medulla
52
what do central chemoreceptors detect
changes in arterial pCO2 = more sensitive
53
what are the effects of central chemoreceptors
increase pCO2 = increase ventilation
| decrease pCO2 = decrease ventilation
54
how are pCO2 changes detected by central chemoreceptors
1. higher CO2 in blood = higher H+ but H+ impermeable to BBB
2. CO2 diffuse to CSF
3. react with CSF H2O = increase H+
4. H+ detected by medulla chemoreceptors
55
what is alveolar recruitment
opening of collapsed alveoli
56
what is hypoxia
oxygen deficiency at tissue level
57
paCO2
arterial CO2
58
PACO2
alveolar CO2
59
PaO2
arterial O2
60
PAO2
alveolar O2
61
PIO2
pressure of inspired O2
62
VA
alveolar ventilation
63
VCO2
CO2 production
64
where does Hb dissociate with O2
in areas of low pO2 = metabolically active tissue
65
effect of high temperature on oxygen dissociation curve
shift to right = Hb has less affinity for O2
66
effect of low pH on oxygen dissociation curve
shift to right = Hb has less affinity for O2
67
effect of carbon monoxide
22x affinity for Hb than O2 = shifts curve to the left = decreases unloading of O2 from Hb to tissues
68
3 ways CO2 carried in blood
1. bound to Hb as carbaminohaemoglobin = 23%
2. plasma dissolved = 10%
3. as HCO3- = 65%
69
acid base dissociation equation
CO2 + H2O = H2CO3 = HCO3- + H+
70
does deoxy or oxyhaemobglobin have a higher affinity for H+
deoxyhaemoglobin
71
what is Dalton's law
total pressure = sum of partial pressures
72
what is Boyle's law
pressure of a fixed amount of gas in a container is inversely proportional to containers volume P1V1 = P2V2
73
what is Henry's law
at equilibrium the pp of gas molecules in liquid and gaseous phases must be identical
74
what is the alveolar gas equation
PAO2 = PiO2 - PaCO2/R
| where R is the resp exchange ratio
75
what is the respiratory exchange ratio
ratio between amount of CO2 produced in metabolism and O2 used
76
pressure =
flow x resistance
77
what is the Law of Laplace
describes the relationship between pressure, surface tension (T) and radius of an alveolus
P = 2T/r
78
what is lung compliance
Cl = change in lung volume caused by given change in transpulmonary pressure = greater Cl = more readily the lungs expand
79
what is the significance of type 2 pneumocytes in the alveoli
produce surfactant = reduced cohesive forces between water molecules = lowers surface tension = increase lung compliance
80
what is the significance of surface tension in the alveoli
= attractive forces between water molecules = resists stretching = lungs require energy to overcome these forces
81
what is the henderson hasselbach equation
pH = 6.1 + log10 ( [HCO3-]/[0.03 * PCO2] )
82
what causes respiratory acidosis
hypoventilation = inadequate ventilation of alveoli = CO2 cannot be excreted adequately = pCO2 increase = H+ increase in blood
83
what causes respiratory alkalosis
hyperventilation = decrease arterial pCO2 = decrease H+ conc
84
how is acid base balance restored
alter respiratory rate = change pCO2
| urinary system change reabsorption/production of HCO3- or H+
85
4 causes of hypoxia
1. hypoventilation
2. diffusion impairment
3. shunting
4. ventilation/perfusion mismatch
86
what occurs in diffusion impairment
thickening of alveolar membranes or decrease in SA = PaO2 and PAO2 cannot equilibrate
87
what occurs in shunting
anatomical abnormality
= mixed venous blood bypass ventilated alveoli
= mixed venous blood perfuses unventilated alveoli
88
what is hypercapnia
CO2 retention and increased PaCO2
89
what causes hypercapnia
hypoventilation
90
what occurs in type 1 respiratory failure
pO2 is low
pCO2 is low or normal
hypoxia
91
what can cause type 1 respiratory failure
pulmonary embolism
92
what occurs in type 2 respiratory failure
pO2 is low
pCO2 is high
hypercapnia
93
what causes type 2 respiratory failure
hypoventilation
94
what is inspiratory reserve volume IRV
amount of air in excess tidal inspiration that can be inhaled with maximum effort
95
what is expiratory reserve volume ERV
amount if air in excess tidal expiration that can be exhaled with maximum effort
96
what is residual volume RV
amount of air remaining in the lungs after maximum expiration = keeps alveoli inflated between breaths and mixes fresh air on next inspiration
97
what is vital capacity VC
amount if air that can be exhaled with maximum effort after maximum inspiration = ERV + TD + IRV
98
why do we test vital capacity
used to assess strength of thoracic muscles + pulmonary function
99
what is functional residual capacity FRC
amount of air remaining in lungs after normal tidal expiration = RV + ERV
100
what is inspiration capacity IC
maximum amount of air that can be inhaled after normal tidal expiration = TV + IRV
101
what is total lung capacity TLC
maximum amount of air the lungs can contain = RV + VC
102
what is tidal volume TV
amount of air inhaled or exhaled in one breath = 500ml per breath
103
what is FEV1
forced expiratory volume in 1 second
| approx 80% in 1 sec
104
what is forced vital capacity FVC
total amount of air forcibly expired
105
describe a flow volume curve
shows forced expiration = flow is greatest at start of expiration and declines linearly with volume
106
what does a low FVC indicate
airway constriction
107
what is the FEV1/FVC ratio
proportion of FVC exhaled in the 1st second = FEV1/FVC
108
what is airway obstruction indicated by
low FEV1/FVC ratio = below 0.7 but normal FVC
109
what is airway restriction indicated by
FEV1/FVC ratio high (normal) or lower than 80% but FVC is low
110
what are the characteristics of pulmonary circulatory vessels
thin walls
minor muscularisation
no need for redistrobution
111
what are the characteristics of systemic circulatory vessels
thick walls
signification muscularisation
redistribution is required
112
what has higher pressures, systemic or pulmonary circulation
systemic
113
conditions for vasoconstriction/vasodilation in pulmonary vs systemic vessels
```
pulmonary = if lack of o2 then vasoconstriction occur to divert away from poor ventilation
systemic = if lack of o2 then vasodilation to increase blood flow and therefore o2 to that area
```
114
name 2 structural and functional changes to the lung with ageing
1. delayed response to hypoxia/hypercapnia = vulnerable to vent failure
2. FEV1 and FVC decrease = may indicate obstructive and so may mask respiratory symptoms/disease
115
how is gas exchange impaired in the ageing lung (7)
1. costal catilages stiffer
2. respiratory muscle mass decrease
3. reduction in type 2a muscle fibres = fast-fatigue resistant ones = more tired when breathing
4. denervation of muscle fibres = less contraction
5. loss of elastic recoil
6. V-P mismatch increase
7. reduced alveolar SA and lung blood flow
116
what are the effects on the immune system of the lung with ageing (3)
1. fewer glandular epithelial cells = less protective mucus
2. decrease sputum clearance
3. less effective mucociliary system
117
when is IgE made
in response to things were allergic to
118
who tf are gell and coombs
they classified hypersensitivity into 4 types
119
type 1 gell and coombs
IgE = causes an acute immediate allergic reaction
| e.g. acute anaphylaxis/hayfever
120
type 2 gell and coombs
IgG bound to cell surface antigens = fairly quick attacks bodies own cells
e.g. transfusion reactions /autoimmune disease
121
type 3 gell and coombs
immune complexes deposited causing local inflammation = IgG
| e.g. post streptococcal/SLE/ farmer's lung
122
type 4 gell and coombs
T cell mediated delayed type hypersensitivity (DTH) = granulation tissues
e.g. TB/contact dermatitis
123
what is an allergen
an antigen that causes an allergic reaction
124
what is atopy
an inherited exaggerated IgE response to antigens
125
what occurs in initial exposure to antigens
some antibody synthesis and production of B memory cells
126
what occurs on exposure to allergen in type 1 reactions
1. allergens are presented by B cells
2. this activates t helper cells = help produce IgE antibodies + trigger mast cells
3. mast cells secrete inflammatory mediators = initiate local inflammatory response
127
what are the inflammatory mediators in type 1 reactions
histamine and chemokines
128
what are the effects of histamine in acute inflammation
```
bronchoconstriction = difficulty breathing
vasodilation = swelling
```
129
how does vasodilation lead to signs of acute allergic reaction
more blood flow = redness
| greater permeability = fluid moves out of cells = swelling
130
what causes anaphylaxis and what are the symptoms
mast cells secrete large amount of mediators = enter circulation
leads to severe hypotension, vasodilation, bronchoconstricion + mucus hypersecretion
131
what neurotransmitter is associated with parasympathetic nerves supplying the airways
acetylcholine
132
what is the intrinsic tone of the airways governed by
parasympathetic NS
133
what type of receptor does acetylcholine interact with
muscarinic = M3 cholinergic receptors
134
what does an increase in parasympathetic activation of the airways lead to
= too much Ach = bronchoconstriction
135
what neurotransmitter is associated with sympathetic nerves supplying
noradrenaline NAd
136
what part of the airways are innervated by parasympathetic
vasculature, glands, airways in lungs via vagus
137
what part of the airways are innervated by the sympathetic
does not directly innervate airways
| = vasculature and glands
138
what is the effect of sympathetic activation
cause NAd to be released to adrenal glands = release adrenaline = binds to beta-2-adrenoreceptors on airway muscles = broncodilation
139
where are nicotinic receptors found
post-ganglionic neurons and neuromuscular junction
140
what is the action of beta-adrenergic receptors in the lung
act via stimulatory G proteins = increase cyclic AMP in postsynaptic cell
141
what is the action of cAMP
diffuses in the lung = decrease calcium coc = results in bronchodilation
142
what do nicotinic receptors respond to
acetylcholine and nicotine
143
what is the difference between nicotinic and muscarinic receptors
```
nicotinic = acts as channel for +ve ion, usually Na+ = always excitatory
muscarinic = use G protein
```
144
how does respiratory epithelium protect the airways
- moistens and protects
- acts as barrier
- prevent infection/injury by mucociliary escalator
145
name 3 secretions of the epithelium
antibodies
lysozyme
lactoferrin
146
what does lactoferrin do
binds to iron to prevent bacteria from accessing iron it needs to function
147
what does respiratory epithelium and upper GI tract secrete
mucus
148
how does mucus defend
contains antibodies
| very sticky - prevent particles from entering blood
149
name 2 chemical barriers that respiratory epithelium produces
anti-fungal peptides
| anti-microbial peptides
150
what is a cough
explosive expiration to clear tracheobronchial tree of secretion/foreign material
151
where are the receptors of the cough reflex found
larynx/trachea/bronchi
152
what are the 2 processes by which a cough may be initiated
voluntarily or reflexively
153
describe the mechanism of a cough
1. receptors stimulate inspiratory neurons on medulla = deep inspiration
2. epiglottis/vocal cords trap air in lung
3. abdominal/internal intercostals contract forcefully = pressure in lungs rises
4. positive intrathroacic pressure = narrowing of trachea
5. vocal cords/epiglottis open wide suddenly = air expelled at 75-100mph
154
why do the vocal cords/epiglottis open so suddenly in coughing
large pressure difference between airways and atmosphere + tracheal narrowing = rapid flow rates through trachea
155
what is airway mucus
viscoelastic gel containing water, carbs, proteins
156
where/what secretes mucus
goblet cells of airway surface epithelium
| submucosal glands
157
what is the role of mucus
1. protects epithelium from foreign material + fluid loss
| 2. transported to from lower resp tract to pharynx by airflow + mucociliary clearance
158
what is the role of the muco-ciliary escalator
1. constantly brings mucus up airway by cilia beating in directional waves
2. protects epithelium by physical contact
159
what are type 1 pneumocytes
thin flat squamous cells lining 95% of alveolar surface
160
what is the role of type 1 pneumocytes
involved in gas exchange
161
what are type 2 pneumocytes
granular cuboidal cells of alveoli typically found at blood air barrier
162
what are alveolar macrophages
roam freely within alveoli and phagocytose material/cell debris
163
where do alveolar macrophages develop from
differentiate from monocytes in main blood stream
164
what happens to macrophages that carry particulates (3)
1. enter respiratory/terminal bronchioles
2. adhere to ciliated mucus-coated epithelium = 1st step of muco-ciliary escalator
3. carried up to trachea then cleared in mucus by coughing
165
what is adaptive immunity
response to pathogen following initial exposure = slower response to specific microbes
166
what are T cells
type of lymphocyte involved in cell-mediate immunity and direct killing of cells
167
where are T cells made
in bone marrow but mature in the thymus
168
what do cytotoxic T cells do
travel to target location
bind to target via antigens on target
directly kill target via secreted chemicals
169
what do T helper cells do
assist in activation and function of B cells/ macrophages/cytotoxic T cells
170
what is the role of antigen presenting cells
phagocytose foreign material
process and present antigen
activate lymphocytes
171
what are the properties of the adaptive immune response (4)
1. specific
2. self-tolerance
3. pathogen elimination
4. immunological memory
172
what are B cells
type of lymphocyte
| involved in antibody production
173
how do B cells make antibodies
activated by T helper then differentiate into plasma cells = secrete antibodies
174
where are B cells made
made and mature in bone marrow but stored in secondary lymphoid organs
175
name the 5 types of antibodies
```
IgA
IgD
IgE = allergens
IgG = most abundant
IgM
```
176
how do T helper cells activate B cells (3)
1. migrate to antigen site and undergo activation
2. migrate to B cell activation site
3. antigen presenting B cells make direct contact with antigen specific T cells via surface receptors + cytokine secretion = B cell activation
177
how much is 1atm
10m of water
178
boyles law with lungs at depth
P1V1 = P2V2
| remember 1atm at the surface
179
importance of henrys law with lungs at depth
= proportionally more gas dissolves in tissues at depth
| so if ascend faster than rate of gas clearance = results in decompression illness
180
what is the diving reflex with free diving
aponea = stop breathing
bradycardia
peripheral vasoconstriction
181
what is FiO2
fraction of inspired O2 = never changes = 0.21
182
explain why the PiO2 at sea level is 21KPa
Patm x Figas = 100kPa x 0.21 = 21KPa
183
what is classed as extremely high altitude
18000 ft = 5400m
184
pressure of arterial CO2 (PaCO2) is directly proportional to
1/alveolar ventilation
185
what is the alveolar gas equation
```
PAO2 = PiO2 - PaCO2/R
R = co2 produced - o2 consumed = 0.8 with normal diet
```
186
arterial pressure of O2 (PaO2) =
PAO2 - (A-aDO2) = difference between arterial/alveolar O2
| = 12.5 - 1 = 11.5KPa
187
what is A-aD
arterial-alveolar difference
| tends to be 1KPa
188
normal PaO2 at sea level
10.5-13.5KPa
189
normal PaCO2 at sea level
4.5-6KPa
190
effect of altitude on pressure
as altitude rises pressure decreases but not linearly
need to be 5000m to halve barometric pressure
FiO2 remain constant 0.21
PiO2 falls
191
effect of altitude on lungs (3)
1. hypoxia lead to hyperventilation results in increase minute ventilation/lower PaCO2
2. initial alkalosis - compensated by renal bicarb excretion
3. tachycardia
192
name 2 high altitude illnesses
acute mountain sickness
| high altitude pulmonary oedema
193
where is the respiratory tract derived from
foregut endoderm and associated mesoderm
194
what develops from the endoderm
1. trachea epithelial lining
2. larynx
3. bronchi
3. alveoli
195
what develops from the splanchnic mesoderm
1. cartilages
2. muscle
3. connective tissue
4. visceral pleura
196
what happens at 4th development
lung bud forms - initially as respiratory diverticulum from foregut endoderm
197
what is the pseudogladular stage
5-16 weeks
| branching of buds to form terminal bronchioles + angiogenesis
198
what is the canalicular stage
16-26 weeks
| each terminal bronchiole divides into respiratory bronchioles = divide into ducts
199
what is the saccular stage
26 weeks - birth
| terminal sacs and capillaries form = 1/6th the adult no. of alvoli at birth
200
what is the alveolar stage
8months - childhood
| alveoli mature/more resp bronchioles and alveoli
201
what is the PaO2 in a foetus
3.2PKa
202
why is blood shunted in foetal heart
high vascular resistance in lungs = pressure higher in right side of heart = blood shunt to left through foramen ovale
203
what is the effect of high oxygen on systemic circulation in a foetus
in hypoxia = vasodilation to allow more o2 to tissues so in high oxygen = vasoconstriction as not as much o2 required
204
what is the role of oxygen in pulmonary circulation of the foetus
in hypoxia = vasoconstriction
| in high oxygen = vasodilation as allows more o2 to be picked up
205
what occurs in the lungs at birth
1. fluid in lungs is squeezed out by birth process
2. adrenaline released due to stress = increases surfactant release
3. air is inhaled
4. oxygen vasodilates pulmonary arteries
206
what occurs to the umbilical arteries and ductus arteriosus at birth
constrict to become the medial umbilical ligament and ligamentum arteriosum respectively
207
how is blood moved to lungs at birth
pulmonary artery pressure goes down and aortic pressure goes up so blood moves into lungs via diffusion to be oxygenated
208
when is surfactant produced in the foetus
from 34 weeks gestation
| dramatic increase 2 weeks prior to birth
209
what occurs in respiratory distress syndrome of the newborn
type 2 pneumocytes are too immature to function = low surfactant levels = decrease lung compliance = breathing causes exhaustion/lung collapse/death
210
what is respiratory epithelium
pseudostratified ciliated columnar epithelial cells interspersed with goblet cells
lines tubular portions of respiratory tract
211
what epithelium lines the nose
keratinising and non-keratinising squamous epithelium
| respiratory epithelium
212
what is olfactory epithelium
roof of nasal cavity/lateral walls = pseudostratified columnar epithelium of olfactory cells - serous glands of bowman lie below
213
what are sustenacular cells
tall narrow in contact with basement membrane
have bulky cytoplasm near lumen = accumulates yellow/brown pigment
= support olfactory epithelium
214
what epithelium lines the vocal cords
false folds = upper = respiratory
true folds = lower = stratified squamous
vestibule = between = respiratory
215
vocal cords contain
elastic tissue = conus elasticus
| voluntary skeletal muscle = vocalis muscle
216
what colour do goblet cells stain with H&E stain
white
217
what is a mucosa associated lymph tissue MALT
at connective tissue in bronchius = no capsule, intimately related to epithelium
218
what epithelium lines the terminal/respiratory bronchioles
simple cuboidal epithelium sparsely ciliated + has spirally arranged smooth muscle and no cartilage
219
where are clara cells found
in terminal bronchioles = secretory and synthetic so have large ribosomes/ER/granules
220
type 1 pneumocytes appear
thin + 40% population
221
type 2 pneumocytes appear
globular, round, dark staining nuclei
222
what happens to fixed/septal macrophages
remain in interstitium between cells/tissue
223
how to distinguish pulmonary vessels from systemic
pulmonary = longitudinally running elastic fibres in walls
- well defined medial
- well defined elastic tissue
224
where will fibroblasts be found
in walls of alveoli = produce collagen type 3 (reticulin) and elastic tissue for recoil
225
what is the structure of the visceral pleura
```
flat mesothelial cells
loose fibrocollagenous tissue
irregular ext elastic layer
interstitial fibrocollagenous layer
irregular int elastic layer
```
226
what type of response do central chemoreceptors provide
slow response
227
what type of response fo peripheral chemoreceptors provide
rapid response
228
what is a pulmonary embolism
blood clot prevent perfusion of lungs
229
what is pneumonia
infection prevents ventilation of alveoli
230
how does copd affect the body
less gas exchange SA
| in expiration airway collapses = trap air in chest = buildup of CO2
231
how does asthma affect the body
can expire CO2 faster than can receive O2
hypoxic because low O2 but normal CO2 = type 1 resp failure
long term become hypercapnic
232
what is the term to describe malignant tumour in pleural membranes
mesothelioma
233
what conditions lead to type 1 resp failure
pulmonary embolism
| V/P mismatch
234
what condition may lead to type 2 resp failur
opioid overdose
235
what is PEF
peak expiratory flow = effort dependent
236
what is FEF
forced expiratory volume
| FEF25 = forced expiratory flow rate when 25% volume has been expelled
