Repiratory Flashcards
Phase 1 respiratory lectures, histology and anatomy (222 cards)
1
Q
Name 4 Functions of the Nose
A
- Temperature control
- Humidity Control
- Filter / Defence function
- Olfactory
2
Q
What are the Turbinates and what is their funtion?
A
Superior meatus
Middle meatus
Inferior meatus
Three large shelves that increase the SA for temp regulation.
3
Q
What is the superior meatus proximal to?
A
Olfactory epithelium
Cribriform plate
Sphenoid Sinus
4
Q
What is the Middle Meatus proximal to?
A
Sinus Openings
5
Q
What is the inferior meatus proximal to?
A
Nasolacrimal duct
6
Q
Label the Paranasal Sinuses
A
7
Q
The Frontal Sinus is found…
It is innervated by….
Drains into….
A
…Within the frontal bone, Over Orbit and across superciliary arch
….Opthalmic division of V
…. middle meatus
8
Q
The Ethmoid Sinus is found….
It opens up into the…
It is Innervated by…
A
…between the eyes
…superior and Middle Meatus
…Opthalmic and Maxillary V
LABRYINTH of air cells
icecream headache
9
Q
The Maxillary Sinus is found…
It is …. shaped
It drains into the….
innervation?
A
….within the body of the maxilla
…pyramidal…
…Middle meatus (Semilunar Hiatus)
Maxillary (V2)
10
Q
The Sphenoid Sinus is found medial to…
Inferior to…
It empties into the…
It is innervated by….
A
…Cavernous sinus: Carotid artery, III, IV, V VI (OTOMCAT)
…optic canal, dura, pituitary gland
…sphenoethmoidal recess, lateral to the attachment of the nasal septum
…Opthalmic V
11
Q
name the three parts of the pharynx.
bonus: its muscles?
A
Nasopharynx
Oropharynx
Laryngopharynx
12
Q
What is the function of the Larynx?
A
prevents liquids and foods entering lung
13
Q
how many cartilages in larynx?
A
9
3 pairs, 3 singles
14
Q
label the cartilages of larynx
A
15
Q
where would an emergency airway be made?
A
cricothyroid membrane
16
Q
What is the larynx innervated by?
A
the Vagus (X)
which divides into:
* Superior laryngeal nerve (internal external)
* Recurrent laryngeal nerve (left, right)
17
Q
what is the function of the superior laryngeal nerve?
How many muscles does it innervate?
A
motor innervation to 1 muscle - the cricothyroid
18
Q
The recurrent laryngeal nerve loops…
A
…into the thorax,
Left = under the aorta
Right = RSubArt
between the trachea and oesophagus
19
Q
the cricothyroid is innervated by?
all other intrinsic muscles of the larynx innervated by?
A
cricothyroid = superior laryngeal nerve
all other intrinsic larynx = recurrent laryngeal nerve
20
Q
ca
In 1 minute of breathing, how much air is bretahed in approximately?
A
5 litres
CardiacOutpt is about 5 literes per minute too
1 breath = 500ml approx
21
Q
The trachea starts at the [a] and ends at the [b] where it bifurcates
bonus: at which level does the trachea bifurcate?
A
[a] larynx - cricoid cartilage
[b] carina
Carina = sternal angle = T4/5
22
Q
The trachea is made from what kind of epithelium?
A
pseudo-stratified, ciliated, columnar Respiratory epithelium
with goblet cells
23
Q
trachealis cartlidges form […]
A
incomplete semicircles
24
Q
the trachea is very proximal to…
A
…the aorta and superior vena cava
25
which main bronchus is more likely to get things stuck in it and why?
right main bronchi - more vertically disposed
26
the right lung has [...] lobes
what separates them?
three
superior, middle, inferior
serparated by horizontal and oblique fissure
27
the left lung has [...] lobes
what separates them?
two
superior and inferior (plus lingula)
separated by Oblique fissure
28
What allows gas exchange and surfactant production in the alveoli?
Type 1 pneumocyte = gas exchange
Type II pneumocyte = surfactant production
29
# a
adjacent alveoli are connected through [a] which allow the movement of [b]
[a] pores of Kohn
[b] marcophages
30
enodthelial capillaries of the lung have a
fused basement membrane, 1um thick
31
how many division from trachea to alveoli
24
32
what are the layers of gas exchange?
O2 → Type 1 Pneumocyte → Fused Basement Membrane → Vascular Endothelial Cell → RBC
33
which pulmonary pleura has nociception?
parietal = outside
34
What are the muscles of passive Inspiration?
what about active inspiration?
Passive =
* * **Diaphragm** mainly, 70% of volume change (phrenic C3-5 innervation)
* **External intercostals** – lift ribs 2-12, widen thoracic cavity
Accessory =
* **Scalenes** – lift ribs 1&2
* **Pectoralis major** – lift ribs 3-5
* **Sternocleido**. – elevates sternum
35
Muscles of Quiet expiration?
what about Active Expiration
Passive/Quiet expiration = elasitc recoil of lungs, rib cage and diaphram
Active:
* **Internal intercostals** – depresses ribs 1-11
* **Rectus abdominis** – depresses lower ribs, compresses
abdominal organs and diaphragm
36
which nerves innervate the diaphram?
C3, C4, C5
| Keep diaphram alive
37
what is meant by the term static lungs?
Both the chest wall and lungs have elastic properties that require energy to change.
38
Gas Exchange happens via simple diffusion in the [a] and [b] and requires a balance of [c] and [d]
alveoli
capillaries
ventilation (high SA and minimal distance)
perfusion (blood supply)
39
Haemoglobin is fully saturated at [a]% way through the capillary bed
25%
40
# think about heating a house with no one upstairs.
During Hypoxia, whay happens to the pulmonary circulation?
Pulmonary Vasoconstriction Occurs in the hypoxic areas
why: ultimately to rebalance the ventilation:perfusion ratio
If an area of lung not getting any oxygen, no point in perfusion. Lung shuts blood flow to that area/alveoli and concentrates on perfusing the areas that do have oxygen.
| opposite to systemic circulation!
41
what is deadspace and where is it found?
the volume of air not contributing to ventilation.
Physiological = anatomical = alveolar
150ml anatomic (airways)
25ml Alveolar (damage)
42
how many orders of branching in lungs?
17 orders
43
perfusion of capillaries depends on:
pulmonary artery pressure
pulmonary venous pressure
alveolar pressure
44
what is PaCO2?
arterial CO2
45
what is PACO2?
alveolar CO2
46
What is PiO2?
Pressure of inspired O2
47
what is FiO2?
Fraction of inspired O2 = 0.21
48
what is the relationship between arterial CO2 and alveolar ventilation?
PaCO2 = kVCO2 / VA
arterial CO2 is inversely proportional to Alveolar ventilation.
If you hyperventilater (increase VA), will reduce arterial CO2
49
What is the alveolar gas equation?
50
Name four causes of Hypoxaemia (Low PaO2 in blood) (hypoxia = low o2 to tissues)
1. Alveolar hypoventilation
2. Reduced PiO2
3. Ventilation:Perfusion mismatching
4. Diffusion abnormality
51
Why is O2 / HbO2 curve sigmoid shape? (non-linear)
As each O2 molecule binds, it alters the confromation of haemoglobin, making subsequent binding easier
## Footnote
influences, by CO2, Temp
52
What can be measured from blood gases?
PaCO2
PaO2
pH
HCO3-
53
what is the normal pH of human body?
| ACID BASE CONTROL
7.35-7.45
54
CO2 is predominantly controlled by...
Respitory control
55
HCO3- is predominantly under...
renal control
| slower than rep. control of CO2
56
The respitory system is able to compensate for increased [...] but elimination of fixed acids depends on the [...]
carbonic acid production
renal system
57
what will happen to the blood pH if ventilation is impaired?
how will the renal system compensate
Henderson-Hasselbach equation:
Increase PCO2, decreases pH = repiratory acidosis
retention and prodcution of HCO3- and H+ secretion to compensate
58
during hyperventilation what happens to blood pH?
Resiratory alkalosis
59
Lung expansion is limited by [a]
[a] is determined by the amount of [b] and [c]
[c] is reduced by [d]
[a] compliance
[b] elastic tissue
[c] surface tension in alveoli
[d] surfactant
60
How is mucus removed from the lungs?
mucociliary escalator.
cillia beat in directional waves to move mucus up the airway to be swallowed
61
Chemical epithelial barriers, secreted from respiratory epithelial have multiple functions including:
antiproteinases
anti-fungal peptides
anti-microbial peptides
antiviral proteins
opsins
62
mucus is produced by which cells
goblet cells
63
what is airway mucus?
viscoelastic gel containing water, carbs, proteins and lipids.
64
mucus protects the epithelium from (2x)
foreign materials and fluid loss
65
coughing is a [a] reflex
expulsive
with some voluntary control
66
respiratory epithelium is able to regenerate largely due to its [a]
In other words they dont [b]
[a] functional plasticity
[b] terminally differentiate
67
what is functional plasiticity?
When a cell is able to change their phenotype - redifferentiate into another type of cell
68
what is surfactant produced by and what is its function?
type II pneumocytes.
Reduce surface tension of lungs
69
How many layers in the aveolar blood-air barrier?
what are they?
Three:
(surfactant)
1. Type I pneumocyte
2. Fused Basement membrane of pneumocyte and capillary
3. Vascular Endothelial Cell
70
which types of alveolar cells make up most of the surface area?
which types are more numerous?
Type I pneumocytes make up 90% of SA (very thin!)
But Type II make up 60% of cell population
71
Alveolar macrophages are derived from [a] and [b] particulates including dust and bacteria and leave via the [c] or [d]
[a] Monocytes
[b] phagocytose
[c] lymphatics
[d] mucociliary escalator
72
where would serous glands of bowman be found and what is their function?
in the olfactory epithelium (apex of roof of nose and some of nasal cavity and septum)
secrete watery fluid which help wash the surface clean.
73
where would clara cells be found?
in the terminal bronchioles
## Footnote
uncertain purpose ? secrete lipoprotein which prevent bronchioles sticking tog? surfactant elimination?
74
What is the larynx comprised of?
What are the vocal chords comprised of?
Larynx: Respiratory epithelium; hyaline cartilage, with seromucinous glands.
Vocal chords = stratified squamous epithelium over loose irregular fibrous tissue (Reinke space) no Lymphatics.
75
What are the pores of Kohn and what do they do?
why can they cause issues?
Holes in the alveoli interstitium - connect alveoli
they help equalise pressure between adjacent alveoli
means that they can spread infection between alveoli.
76
What are the two circulatory sysstems of the lungs?
1. Pulmonary (100% ofCardiac Output)
2. Bronchial (2% of LV output)
77
what is the transit time of a RBC around the pulmonay circulation?
around 5 seconds
78
what is a normal pressure in the RA?
5mmHg
79
What is a normal pressure in the Left atrium?
5mmHg
80
What is a normal pressure in the Right Ventricle?
What is a normla pressure in the Left Ventricle?
Right Ventricle: 25/0
Left Ventricle: 120/0
81
what is a normal aortic pressure?
what is a normal pulmonary artery pressure?
aortic pressure: 120/80
pulmonary artery: 25/8
82
what does the pulmonary arterial wedge pressure measure? (PAWP)
pressure in the left atrium
83
what is the equation for calculation average blood pressure?
(Mean pulmonary arterial pressure - pulmonary arterial wedge pressure?
mPAP - PAWP = CO x PVR
mPAP = mean pulmonary arterial pressure
PAWP = pulmonary arterial wedge pressure
CO = Cardiac Output
PVR = Pulmonary vascular resistance
84
why does the radius of a blood vessel have such a disproprtionate effect of resistance?
Pouiseuilles Law
85
how is mPAP able to remain stable during exercise, despite increased CO?
| mPAP - PAWP = CO x PVR
autoreuglation of blood flow
metabollic/myogenic
86
What are some causes of Type II Respiratory failure?
PaCO2 > 6 kPa
| PaO2 < 8 kPa
WHOLE LUNG
Failure to ventilate: PUMP FAILURE.
*Hypoventilation
* Muscular weakness
* Obesity
* Posture
* Loss of respiratory drive eg opiods
* COPD
87
what are some causes of Type I Respiratory Failure?
PaCO2 < 6 kPa
| PaO2 < 8 kPa
Hypoventilation
Diffusion Impairment - eg pneumonia
Shunting
V/Q mismatch - pulmonary embolism
(parts of the lung)
88
The average VQ ratio is [a].
[?] exceeds [?] towards the apex, and [?] exceeds [?] towards the base.
The different ratios for different areas are due to the relation of the area to the [?]. Areas of lung [?] have [?] perfusion relative to ventilation due to [?], reducing the V/Q ratio.
**0.8**
**ventilation ** exceeds **perfusion** towards the apex, and **perfusion** exceeds **ventilation** towards the base.
The different ratios for different areas are due to the relation of the area to the heart. Areas of lung **below the heart** have **increased** perfusion relative to ventilation due to **gravity which increases blood flow**, reducing the V/Q ratio.
89
what are the two types of V/Q mismatch and what are they caused by?
dead space and shunt.
Deadspace = ventilation but poor perfusion (pulmonary embolism)
Shunt = perfusion but poor ventilation (arterial venous malformation)
## Footnote
Shunt is the opposite of dead space and consists of alveoli that are perfused, but not ventilated.
90
what physiological problem can a mismatched VQ lead to?
pulmonary embolism
91
What can increased Pulmonary Vascular resistance lead to? (patholoical)
pulmonary arterial hypertension
92
what could a shunt lead to? (pathology)
pulmonary arteriovenous malformation
mix of ox and deox blood
93
Which type of xray, AP or PA are "better" and why. When would the other might have be used?
PA is better: heart is closer to detector so reduces blur
AP may be used is patient bed-bound
## Footnote
On the PA view, the cardiac borders are smaller and more defined. Given the way the x-ray beam works, the heart appears smaller and with sharper borders on the PA view. The reason is that the patient’s chest (anterior) is against the x-ray film with the beam entering from posterior (P) to anterior (A) – hence the term “PA.” Similarly, the AP view is when the beam enters from front to back with the x-ray film at the back of the patient – therefore, the heart is magnified and the margins are minimally less sharp.
94
What is TLC?
Total lung capacity.
Residual volume + Vital Capacity
95
What is Residual Volume and how is it calculated?
air remaining in lungs after max expiration to prevent collapse, ~1.2L
Cannot be calculated directly. But important for TLC = RV + VC
Can be calculated via Gas dilution or Body box
96
What is tidal volume?
volume inhaled/exhaled in a normal breath, ~500ml
97
What is VC?
Vital capacity – max air expired after max inspiration, ~4.7L (ERV +TV + IRV)
98
how can peak expiratory flow be measured?
spirometer
99
What is a transfer estimate and how is it calculated?
(TLCO)
* Transfer estimate gives an overall look into how well lungs are functioning.
* Tiny amount of CO given (incredibly high affinity to haemoglobin), hold for 10 seconds, and see how much is exhaled
* Corrected for volume (eg if have 1 lung)
100
What is FEV1?
What is the normal value for FEV1?
* Forced expiratory volume in 1 second
* >80% of predicted value
101
What is FVC?
What is the normal value of FVC?
* Forced vital capacity
* >80% of predicted value
102
What would a low FVC value (<80% of normal) indicate?
Airway restriction (e.g. lung disease, neuromuscular, Obesity)
103
What would be an abnormal FEV1:FVC ration be?
What would a low FEV1:FVC indicate?
* <0.70
* Low ratio = airway obstruction (eg asthma, COPD)
104
You work in a GP surgery, and suspect a patient you have seen has developed COPD. Spirometry needs to be performed to confirm your suspicions.
What would you anticipate the FEV1 : FVC ratio would be if this patient has asthma?
A.1.3
B.0.8
C.0.6
D.<80% of predicted.
E. 1
c. 0.6
| ratiObstruction (asthma/COPD)
105
what would the flow/volume loop of obstructive lung disease look like vs restrictive?
106
What would be an expected TLC of someone with COPD?
High/Elevated TLC
(Breathing at a higher level in order to get O2 in)
107
where are the respiratory control centres? (Central chemoreceptors)
Pons and Medulla Oblongata in the Brainstem
108
what are the two centres in the pons that adjust the depth and duration of inspiration?
Apneustic: increase depth and duration
pneumotaxic: inhibitory impulses: decrease depth and duration
109
Two groups in the Medulla Oblongata that stimulate various muscles associated with breathing?
Dorsal Respiratory Group (**DRG**) = Inspiration - diaphram and intercostal
Ventral Respiratory Group (**VRG**) = FORCED Inspiration and Expiration - accessory muscles and inhibits apneustic
110
where is the central pattern generator located?
within the DRG/VRG
111
where are the central chemoreceptors located?
Brainstem: Pontomedullary junctions (not in DRG/VRG)
112
what are the cenral chemoreceptors mainly influenced by?
CO2 (60%)
CO2 is the main stimulant to breath
## Footnote
CO2 readily diffuses across blood brain barrier, H+ cannot.
CO2 levels increase = more H+ that cannot diffuse back, so agonise central chemorecpetor. So H+ is the mediator, via the important increase in PaCO2.
113
where are the peripheral chemoreceptors locted?
Carotid bodies and Aortic bodies
114
what are peripheral chemoreceptors stimulated by?
Large reductions in O2, (plus CO2 40% and pH)
115
What are the aortic peripheral chemoreceptors sensitive to?
carotid?
arotic = O2 CO2 (NOT H+/pH)
carotid = ALL THREE
116
carotide bodies innnervation?
aortic bodies innervation?
Carotid bodies - glossopharyngeal nerve
Aortic bodies - Vagus nerve
117
what are the three lung receptors?
**1. Stretch**
Smooth muscle of conducting airways
Sense lung volume.
Slow adapting
**2. Irritant**
Larger conducting airways
Rapidly adapting (Cough, Gasp)
**3. J: Juxtapulmonary capilliaries**
bronchoconstriction in response to irritants
118
What are the 4 airway receptors?
1. Nose - chemo and mechano. monitor flow
2. Nasopharynx - chemo and mechano. monitor flow
3. Larynx - chemo and mechano. monitor flow
4. Pharynx - activated by swallowing to prevent
119
What are the musclle proprioceptors that influence control of breathing?
Joint, tendon and muscle receptors in Intercostan muscles and diaphram.
Perception of breathing effort.
120
What are the indications and parameters of Type I Respiratory Failure?
Low O2, Low/ Normal CO2
<8KPa O2
| hypoxaemia (+/- hypocapnia)
121
What are the indications and parameters of Type II Respiratory Failure?
Low O2, High CO2
<8KPa O2
over6.5KPa CO2
| hypoxaemia and hypercapnia
122
Definition of respiratory failure?
failure of gas exchange =
Inability to maintain normal blood gases
123
which type of respiratory failure is more common?
type I
124
name some specific causes of Type I Respiratory failure:
Infection
COPD
125
name the potential mechanisms of Type I respiratory failure
shunting, VQ mismatch, diffusion impairment, alveolar hypoventilation
126
name the mechanisms of Type II respiratory failure?
Lack of respiratory drive
Excess workload
Bellows Failure
127
name some specific causes of Type II Respiratory failure
COPD
Opiod overdose
Fatal stage asthma
128
In which type of Respiratory Failure would you see Central Cyanosis?
Type II
129
when must you be careful with administering O2 in respiratory failure?
Why?
in patients with COPD.
Their drive to respirate originates from Hypoxia, to remove hypoxia would remove their drive to breath.
130
when would you administer O2 through nasal cannula?
Why?
when patient is more stable.
This method is uncontrolled compared to mask and much O2 can end up in nasopharynx.
131
What does exhaled nitric oxide measure?
eosinophilic airway inflammation.
not diagnostic, but a biomarker for asthma
132
Asthma is a common c---- i---- d---- of the airways characterised by r---- a----- o---- and b----
chronic inflammatory disease
reversible airway obstruction and bronchospasm
133
?% of asthma is occuparionally caused?
15%
134
?% of people worldwide have asthma?
5-16%
135
other than occupational, what are some other causes of asthma?
infectious agents
fungi
pets
air pollution
136
H------- P------ is an inflammation of the alveoli within the lung cuased by sensitivity to inhaled agents.
There a very significant E------ I------
Hypersensitivity Pneumonitis
Environmental Influences
137
Asthma can r-- i- f------- but is not caused by a s----- m------- in 1 gene.
ie does not follow typical M-------- I----------
run in families
single mutation
mendelian inheritance
138
Cystic Fibrosis is a defect on which chromosone?
long arm of chromosone 7?
139
what is the chromosonal defect of CF?
The CFTR protein is abnormal on the long arm of chromosone 7.
## Footnote
The cystic fibrosis transmembrane conductance regulator (CFTR) protein helps to maintain the balance of salt and water on many surfaces in the body, such as the surface of the lung.
140
what is the CFTR protein? What would an abnormality lead to?
Cystic Fibrosis Transmembrane Regulator.
- A transport membrane of epithelial cells
- helps to maintain the balance of salt and water on many surfaces in the body, such as the surface of the lung
- abnormality = dysregulated epithelial fluid
141
what is the most common mutation causing CF?
what genotype classification is this?
F508del = 80% of patients
Class II.
142
what is a Class II CF genotype?
give an example?
when CFTR protein is made but is misfolded.
F508del
143
what is the prevalence of CF?
1/2500
144
what percentage of the population are carriers of CF?
1/25
145
explain the pathophysiology of CF (vicious cycle)
patients get RTI ---> Bronchial Inflammation ---> Resp Tract damage ---> more susceptible to RTI (rogressive lung disease)
146
what is mucostasis, and how does that lead to bronchiectasis in CF?
| widening of bronchi
whenn mucous becomes more viscous which leads to poor ventilation, recurrent infections and eventually bronchiectasis.
147
how are neonates screened for CF?
how did they used to screen?
IRT - Immunoreactive Trypsin
salty sweat
148
What are the pancreatic symptoms of CF?
mucuc blocks exocrine ducts
enzyme insufficiency
149
what are the digestive symptoms of CF?
Bowel disturbances, weight loss, obstruction, constipation
150
What are the reproductive problems with cf?
95% men & 20% women infertile
congenital absence of vas deferens
151
what are the respiratory symptoms of CF?
mucus retention
chronic infection, inflammation = destroys lung tissue
wheezing and SOB
Sinusitis, Nasal Polyps
152
what drug is a bronchodilator?
salbutamol
153
Genotype directed therapies for CF are relatively new.
GIve an example of a breakthrough treatment that is able to increase CFTR funtion
Ivacaftor in G551D (class III)
and
Lumacaftor in F508del (Class II) - corrects folding
154
what would happen with a Alpha -1 antitrypsin deficiency? (AATD)
| protease inhibitor
in the lungs (PiZZ) - lungs would dissolve/digest itself
= higher risk of emphysema
155
the parasympathetic branches of the autonomic nervous system [dilates/contricts] the bronchi
constricts
| rest/digest
156
the sympathetic branches of the autonomic nervous system [dilates/contricts] the bronchi
Lung receives innervation from [a] ganglia of sympathetic chain
-[b] released at preganglionic synapse binds to [c] receptors
-NAd released from postganglionic neurone acts indirectly by stimulating release of [d] from adrenal medulla
-[e] binds to beta-2 receptors on airway smooth muscle causing [f]
dilates
[a] T2-T4
[b] Ach
[c] N1
[d] adrenaline
[e] Noradernaline
[f] bronchodilation
157
Describe the smooth muscle **constriction** in the bronchi is stiumulates
This is Pathologcal in the case of: ?
can be treated by drugs that block the {?} and are called [?]
Parasympathetic:
-Lung receives bilateral innervation from **vagus nerves **(NB: vagus nerve provides parasympathetic innervation to all organs of thorax and abdomen)
-**ACh** released at preganglionic synapse binds to **N1** receptors
-ACh released from postganglionic neurone binds to **M3** receptors on airway smooth muscle causing bronchoconstriction (↑ airways smooth muscle tone)
pathologcal in asthma and COPD
can be treated by drugs that inhibit parasymapthetic system by blocking M3 receptor.
Called anti-muscarins
## Footnote
anti-muscarins inhibit M3, inhibit para, inhibit constriction
antimuscarins are bronchodialtors
salbutamol = bet 2 agonist = dilation
158
describe the smooth muscle
159
Antimuscarins can be inhaled to [relax/constrict] airways in asthma and COPD.
They can be short acting antimuscarinic or long acting antimuscarinic
[relax]
160
Activation of [a] by [a1] on airway smooth muscle causes them to relax by activating [b] and raising [c]
[a] beta2 receptors
[a1] beta2 agonists (Short acting e.g. salbutamol)
[b] adenylate cyclase
[c] Cyclic AMP
161
Type I Gell and Coombs Classification of Hypersensitivity
Mediator:
Mechanism:
Timing:
Examples:
Type I Gell and Coombs Classification
Mediator: IgE - histamine
Mechanism: Antigen interacts with IgE bound to mast cells or basophils
Timing: Immediate
Examples: Anaphylaxis; Hayfever
162
Type II Gell and Coombs Classification of Hypersensitivity
Mediator:
Mechanism:
Timing:
Examples:
Type II Gell and Coombs Classification of Hypersensitivity
Mediator: IgG or IgM
Mechanism: Cytotoxic antibodies bind to self antigen
Timing: hours - days
Examples: Transfusion reactions, Good pastures
163
Type III Gell and Coombs Classification of Hypersensitivity
Mediator:
Mechanism:
Timing:
Examples:
Type III Gell and Coombs Classification of Hypersensitivity
Mediator: Immune complexes
Mechanism:
Timing: 7 - 21 days
Examples: Hypersensitivity pneumonitis: farmer’s lung, malt worker’s, pigeon fancier’s, paprika
slicer’s
164
Type IV Gell and Coombs Classification of Hypersensitivity
Mediator:
Mechanism:
Timing:
Examples:
Type IV Gell and Coombs Classification of Hypersensitivity
Mediator: T-Cells
Mechanism: Release cytokines
Timing: 2-3 days
Examples: Tuberculosis, contact dermatitis
165
What is meant by the term prophylaxis?
Prophylaxis is a treatment or action taken to prevent a disease developing
166
Which drugs are given for prophylaxis, and which for acute treatment?
Tiotropium is given for prophylaxis; it is a long acting anticholinergic bronchodilator and prevents exacerbations of chronic obstructive airways disease (COPD).
Salbutamol is a short acting beta agonist , which acts as a bronchodilator and is used as and when symptoms arise (prn).
167
Pressure increases by 1atm every Xm of water descended.
10m of water
168
what is Boyle's law?
P1V1 = P2V2
Pressure of fixed mass of gas is inversely proportional to its volume.
Increasing P Decreases V
169
what is Dalton's law?
The total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual component gases.
170
Henry's law
The amount of gas that is dissolved in a liquid is directly proportional to the partial pressure of gas above the liquid
171
what is the alveolar gas equation
## Footnote
The alveolar gas equation is used to calculate alveolar oxygen partial pressure as it is not possible to collect gases directly from the alveoli. The equation is helpful in calculating and closely estimating the PaO2 inside the alveoli. The variables in the equation can affect the PaO2 inside the alveoli in different physiological and pathophysiological states.
172
At 10msw, same PaO2 as breathing [X] % O2 at sea level - therefore SCUBA needs to adjust composition of gases delivered
42%
173
What is Lorrain Smith Effect and what are its parameters?
Pulmonary Oxygen Toxicity
PiO2 > 0.5 ATA
174
what are the symptoms of Lorrain Smith Effect?
| pulmonary oxygen toxicity
Cough, Chest tightness, Chest Pain, SOB
175
What are the effects of CNS oxygen toxicity?
| ConVENTID
ConVENTID
CONvulsion
Vision (tunnel vision)
Ears (tinitus)
Nausea
Twitching
Irritability
Dizziness
176
Inexperienced diver at 50m under sea diving on air.
Begins to feel cold, euphoric, unable to make decisions.
what does this indicate?
what is the cause?
Inert Gas Narcosis
Increased PiN2 causes increase in gas lipid solubility which collects in cells of brain
177
3 hours after 50m diver and quick ascent, women develops significant left arm rash and numbness.
what has happened?
what is the cause?
decompression illness
N2 relatively insoluble, quick ascent causes that which has dissolved to form bubbles in circulation due to drop in pressure.
Initially causes rash & joint pain (Type I/the bends) but can lead to neuro impairment (type II)
Treatment = O2 and urgent recompression
178
Inexperienced diver in swimming pool scuba dive to 3m on air panicks andreturns to surface quickly. Within 3 minutes developed a progressively weak right arm then generalised seizure.
What has happened?
How is this caused?
Treatment?
Arterial Gas Embolism
rapid overexpansion of pulmonary veins on resurfacing can cause tears to vessel walls and entry of gas (**pulmonary barotrauma**). Boluses of gas bubbles can collect in systemic arteries and causes an embolism
Treatment = urgent recompression
179
what is PiO2 at sea level?
21kPa
180
What is a normal PaO2 blood gas?
10.5-13.5 KPA
181
what is a normal CO2 blood gas?
4.5-6 KPa
182
what is normal atmopheric pressure?
100Kpa
183
Alveolar gas equation again?
PiO2 - (PaCO2/R)
| r = 0.8
184
Arterial CO2 is dependent on what?
PaCO2 = k(VCO2) / VA
185
what is the KPa at 8848m?
33.5KPa
186
What is A-aDO2 and what would a normal value be?
what would cause this value to be higher?
Alveolar Arterial O2 Difference.
Normal value = 1KPa
Much higher in someone with emphysema
187
why is the oxygen dissociation curve sigmoidal?
because it is influenced by the changing affinity for sequential O2 binding
188
what factors could affect the oxygen dissociation curve?
Temperature
Acidity (H+)
2,3-diphosphoglycerate (2,3-DPG) levels
PCO2
Increase in these causes shift to the right.
Decrease in these causes shift to the left.
Right shift = ↓ Hb affinity for oxygen
(right = reduced)
Left shift = ↑ Hb affinity for oxygen.
189
how does 2,3-DPG levels affect the OCD curve?
| oxygen dissociation curve: ODC describes relationship between Hb saturat
Chemical found in RBCs
Binds to Hb beta subunits.
Results in less O2 binding sites.
190
how does H+ and PCO2 affect the ODC?
Causes decreased pH which results in reduced Hb affinity for O2.
191
how does temperature affect the ODC?
Causes a conformational change resulting in reduced Hb affinity for O2.
192
explain the RIGHT SHIFT
in order to deliver O2 to the metabolically active areas.
193
at what height does Hypoxia occur?
10,000 ft
194
What is hypoxia at altitude charaterised by?
hyperventilation, tachycardia = lowers PaCO2 = resp. Alk.
195
what is respiratory alkadosis caused by and what is it compensated by?
Low PaCO2 (hyperventilation)
compensated for by renal bicarbonate excretion(removal) and H+ secretion (into blood)
196
Acute mountain sickness is diagnosed using the Laker Louise Score.
What are the criteria of lake louise scores?
1. Ascent over 2500m within the last 4 days
2. Presence of a headache
PLUS
3. Presence of at least one other symptom
4. A total score of 3 or more from headache, GI issues, fatigue, dizziness, sleep disturbance (each on a scale of 0-3)
197
198
What are the symptoms of high altitude pulmonary oedema, what it is caused by and how is it treated?
leaky alveolar capillaries
cough, SOB
Rapid ascent over 2438m without acclimatisation.
Urgent decent and recompression
199
Pressure of inspired gas =
Pressure of inspired gas = Atmospheric Pressure x Fraction of gas inspired
200
name the four stage of embryonic lung development
1. embryonic
2. pseudoglandular
3. cannicular
4. alveolar
201
where to the lungs derive from?
from the respiratory diverticulum, which is an outbranch of the foregut
202
failure of the trachea and oesophagus to separate is called?
atresia
203
in what embryonic stage does the respiratory diverticulum separate from the foregut?
Embryonic phase (0-5 weeks)
204
what develops in the pseudoglandular phase?
pseudoglandular phase = 5-7 weeks
the conducting airways:
major structural units
cartilage
smooth muscle
cilia
lung fluid
205
what develops during the cannalicular phase of embryological development of the lungs?
16-25 weeks
Vascularisation, resp. bronchioles, alveolar ducts, terminal sacs
206
in what phase of embryology do the majority of alveolars formed?
alveolar (25 weeks +) up to age 5
207
when does surfacant start to be produced?
from week 34
208
what is the ductus arteriosus?
shunts the pulmonary trunk to the aorta. (shunts what isnt bypasssed by foramen ovale)
Blood bypasses pulmonary circulation
209
What is the ductus venosus?
the ductus venosus shunts 30% of oxygenated blood directly to inferior vena cava, bypassing the liver
210
what is the foramen ovale?
passage between the two atria
bypasses the majority of the circualtion
211
why does fetal blood go through the three fetal shunts?
becasue pulmonary pressure is high (alveolar all closed) so blood choses the path of least resistance and goes to aorta.
212
what happens during a baby's first breath?
1. Fluid queezed out of lungs by birth
2. Adreniline stress leads to increased surfactant release
3. Gas inhaled
4. Oxygen vasodilates pulmonary arteries dilate = resistance falls
5. SWITCH IN CIRCULATORY PRESSURES CLOSES FORAMEN OVALE AND DUCTUS ARTERIOSUS AND UMBILICAL ARTERIES CONSTRICT
213
name the structures present in the hilum of the lung
1. bronchus
2. pulmonary artery
3. pulmonary vein
214
how many segmental bronchi are in each lung?
215
bronchial arteries branch from the [a]
bronchial veins drain into the [b]
Bronchial arteries and veins supply OXYGEN and NUTRIENTS to the lung tissue themselves
Bronchial arteries branch from **descending aorta**
Bronchial veins drain into **azygos veins**
216
blood supplty to the thyroid?
L and R superior thyroid arteries (branch from external carotid)
L and R inferior thyroid arteries (branch from thyrocervical trunk, which is from subclavian artery)
217
major openings of the diaphram (hiatuses)
I ate 10 eggs at 12.
I(IVC)
8(T8)
10(T10)
Eggs (Esophagus)
At (Aorta, thoracic duct)
12(T12)
218
what are the important structures in the anterior triangle of the neck?
Trachea and larynx
Extrinsic muscles of the larynx (suprahyoid and infrahyoid)
Common carotid artery
Internal jugular vein
Nerves
219
6 nerves in the neck?
1. Facial nerve (CN7) - Platysma
2. Glossopharyngeal nerve (CN 9) - Pharynx and carotid sinus
3. Vagus nerve (CN10) -Muscles of the pharynx and larynx
4. Accessory nerve (CN XI) - supplies sternocleidomastoid and trapezius muscles
5. Hypoglossal nerve (CN XII) - supplies muscles of the tongue
6. Phrenic nerve (C3,4,5) - supplies the diaphragm
220
how does oxygen travel in the blood?
98% haemoglobin in RBCs
2% dissolved in blood
221
how does carbon dioxide travel in the blood?
Carbon dioxide travels in the blood in 3 forms:
~ 60-65% is present as carbonic acid (H2CO3)
~ 25-30% is bound to haemoglobin as carbaminohemoglobin
~ 5-10% is dissolved in the blood.
222
contents of the cavernous sinus?
O TOM CAT
