1
Q
Name the laryngeal cartilages
A
2
Q
name the paranasal sinuses
A
- green: frontal sinuses
- red: sphenoid sinuses
- blue: maxillary sinuses
- purple: ethmoid sinuses
3
Q
Muscle that tensions vocal cords
A
vocalis
4
Q
histology
A
- larynx
- contains several plates of hyaline cartilage and a complex arrangment of striated muscles embedded in fibrous connective tissue
- Trachea is respiratory epithelium
- Vocal folds are stratified squamous
5
Q
nerve supply to frontal sinuses
A
opthalmic branch of CN V
6
Q
what is the hiatus semilunaris
A
this is the hole through which all sinuses except the sphenoid open into the middle meatus
7
Q
what structures is the sphenoid sinus close to?
A
- carotid artery
- Cranial nerves
- 3
- 4
- 5
- 6
- NB it is medial to the cavernois sinus
8
Q
what is the nerve supply to the sphenoid sinus
A
the opthalmic nerve
9
Q
9 cartilages of the larynx
A
- Three single
- Epiglottis – barrier that blocks laryngeal opening while swallowing
- Thyroid
- Cricoid
- Six are paired
- Arytenoid (look like little As at the back that are intimately related to the vocal chords)
- Cuneiform
- Corniculate (on the very top of the arytenoid)
10
Q
where would an emergency tracheostomy be done
A
through the crico-thyroid membrane between cricoid and thyroid cartilages
11
Q
A
- lines the conducting airways where no gas exchange happens
- simple or pseudo-stratified columnar ciliated epithelium with non-cilliated goblet cells
- found in the
- nose
- nasopharynx
- larynx
- trachea
- bronchi
- bronchioles
12
Q
innervation of larynx - can you draw the diagram
A
13
Q
where do the left and right laryngeal nerves loop around?
A
- Left: loops under the arch of the aorta and ascends between the trachea and the oesophagus
- Right: loops under the right subclavian
14
Q
why might a lung tumour cause a horse voice
A
it could cause a recurrent laryngeal nerve palsy
15
Q
what is the division between the upper and lower airways?
A
the larynx
16
Q
to which rib does the sternal angle attach?
A
2nd
17
Q
what surface area of gas exchange is there per lung
A
20m2
18
Q
what is the amount of air in and out of the lungs in one minute
A
5L
19
Q
what is the bifurcation of the trachea called?
A
carina
20
Q
what level is the carina
A
T4/5
21
Q
what epithelia is the trachea lined with
A
respiratory epithelium
pseudostratefied, ciliated columnar epithelium with goblet cells
22
Q
how many lobes does each lung have? describe the fissures that seperate them
A
- Right Lung:
- Upper lobe
- Middle lobe
- Lower lobe
- Left lung
- Upper lobe (and lingula)
- Lower lobe
23
Q
what is a terminal bronchiole?
A
it is the last conducting airway before respiratory bronchioles
24
Q
what is the functional unit of the lungs - briefly describe it.
A
- The acinus
- It contains:
- respiratiry bronchiole
- alveolar ducts
- alveoli
25
what are the interconnections between alveoli called
pores of kohn
these ensure equal inflation
26
describe thickness of alveolar walls
* 70% of the surface area of the alveolar sacs is less than 1 micrometre thick (between air sac and capillary lumen) allowing rapid diffusion of gases across this air blood barrier (see later).
* Elsewhere cell nuclei and connective tissue elements add to the thickness of the walls of the aveoli
27
how many alveoli are there per lung?
about 300,000,000
28
Pleura
* Of mesodermal origin
* 2 layers
* Visceral – lung surface
* Parietal – internal chest wall
* Each layer is a single cell thick
* Continuous with each other at the hilum
* Parietal pleura has pain sensation
* Visceral pleura has only autonomic innervation
29
7 layers of gas exchange
1. surfactant
2. aveolar epithelium
3. basement membrane
4. tissue interstitium
5. capillary endothelium
6. red cell membrane
7. Hb binding
30
What is the purpose of surfactant
* reduces surface tension of water that lines the lung
* this increases compliance
* this reduces energy needed to expand the lung
* it also prevents collapse
* It is produced by type II pneumocytes from 24 weeks
* very prem babies can go into respiratory distress if they haven't begun producing surfactant
* breathing is too exhausting
31
describe pump handle rib movements
* ribs move up anteriorly, articulating at the vertebral column
32
describe bucket handle rib movements
* lateral side of ribs move up, articulating with the sternum and vertebral column
33
which nerve innervates the diaphragm
phrenic: C3,4 and 5
34
what is dead space and how is it split up?
this is the volume of air that does not contribute to ventilation
* anatomic: 150mls
* stays in conducting airways
* alveolar: 25ml
* Physiologica: 175ml
* alveolar and anatomical combined
35
what does lung capillary perfusion depend on?
* Pulmonary artery pressure
* Pulmonary venous pressure
* Alveolar pressure
* How low in the lung they are (lower ones preferentially perfused)
36
hypoxia in the lungs
* Hypoxic pulmonary vasoconstriction
* Diverts blood away from the least well oxygenated areas
* This is the opposite of what happens in the body where they
37
what is VA
Alveolar ventilation
38
what is VCO2
CO2 Production
39
3 ways CO2 is carried in the blood
(i) Bound to Haemoglobin (protein chain) 23% approximately
(ii) Plasma dissolved CO2
(iii) As HCO3-
40
innervation of maxillary sinus
maxillary branch of trigeminal (V2)
41
innervation of the ethmoidal sinus
opthalmic and maxillary branches of the trigeminal nerve
(V1 and V2)
42
innervation of the sphenoid sinus and where it drians into
drains through the sphenoethmoidal recess into the superior meatus
Innervated by opthalmic branch of the trigeminal V1
43
what is the inferior border of the oropharynx?
the epiglottis
44
what is the inferior border of the laryngopharynx
the cricoid cartilage
45
what are the two muscle layers of the pharynx
name the muscles in the layers
what are they innervated by
* Inner longitudinal
* stylopharyngeus
* salpingopharyngeus
* palatopharyngeus
* Outer circular
* superior constrictor
* middle constrictor
* inferior constrictor
* ALL muscle of pharynx are innervated by the vagus except for stylopharyngeus which is innervated by the glossopharyngeal
46
at what vertebral level is the thyroid gland?
C5-T1
47
Label this diagram
48
what vertebral levels does the trachea span?
what innervates it?
C6-T4
innervated by the recurrant laryngeal (CN X)
49
difference in the cartilage between the trachea and the bronchi
Trachea cartilage is C shaped and deficient posteriorly
Bronchi cartilage is a complete ring
50
Trachiobronchial tree
51
cells in the alveoli
* Type I pneumocytes
* less common but cover most surface area
* thin squamous epithelieal cells
* gas exchange
* Type II pneumocytes
* more common but cover less surface area
* lots of cytoplasm and organelles
* produce surfactant
* Alveolar macrophages
* present in the lumen of alveoli and alveolar ducts
52
Inspiration
1. phrenic stimulates diaphragm to flatten
2. volume of thoracic cavity increases
3. chest wall moves away from the lung surface meaning parietal pleura moves away from visceral pleura
4. intrapleural pressure drops
5. transpulmonary pressure increases
6. TP pressure is enough to overcome the intrinsic elastic nature of the lungs
7. lungs expand
8. alveolar pressure drops below that of the atmosphere
9. this draws air into the lungs through the conducting airways
53
what is transpulmonary pressure
this is the difference in pressure between the alveoli and the pleural space (intrapleural pressure)
At rest this is positive because intrapleural pressure is slightly sub atmospheric. This prevents a pneumothorax.
When air enters the pleural cavity this disrupts the sub-atmospheric pressure of the pleural cavity. Due to the elastic nature of the lung it with recoil and 'collapse.'
54
what is intrapleural pressure?
this is the pressure in the pleural cavity
at rest this is slightly sub-atmospheric
55
medullary control of breathing
* Dorsal respiratory group
* fire rapidly during inspiration
* input to C3, 4, and 5 and nerves that control the intercostals
* causes inspiration basically
* Ventral respiratory group
* resp rhythm generator
* located in pre-botzinger complex of neurons
* fires during both inspiration and expiration
* input to muscles of inspiration
56
pontine control of breathing
* Apneustic centre
* lower pons
* major input of medullary inspiration neurons
* terminates inspiration by inhibiting DRG neurons
* Pneumotaxic centre
* upper pons
* modulates activity of apneustic centre and smooths transition from inspiration to expiration
57
Pulmonary stretch receptors
* Slowly adapting stretch receptors (SASR)
* in smooth muscle of airways
* stimulated by large lung inflation
* afferent signals sent to inhibit medullary inspiratory neurons in the DRG
* RASR
* in between epithelieal cells of airways
* stimulated by lung distention
* stimulation causes bronchoconstriction and activity burst
58
Peripheral chemoreceptors: what are they stimulated by and where do they signal to?
* Aortic bodies and carotid bodies
* stimulated by decrease in PaO2, high PaCO2 and an increase in H+
* sends afferent excitaroty input to the medullary DRG to increase rate of respiration
59
Central chemoreceptors
* In the medulla
* provides excitatory input to the medullary inspiratory neurons
* Stimulate ONLY by an increase in H+ in the ECF
60
Hypoxic drive
* Decrease in PaO2 stimulates peripheral chemoreceptors
* Signals are sent to medullary inspiratory neurons
* This increases ventilation rate
61
Control of respiratory drive by CO2
* Increase in PaCO2 causes increase in H+ in blood
* CO2 + H20 --\> H2CO3 --\> H+ + HCO3-
* Stimulates the peripheral chemoreceptors
* Stimulates the central chemoreceptors
* H+ in CSF will also increase
* Both send afferent fibres to inspiratory neurons in DRG of medulla
* Ventilation increases to blow off CO2
62
What is % Hb saturation?
(O2 bound to Hb / maximum capacity of Hb to bind O2) x 100
63
what is Dalton's law?
* AKA law of partial pressure
* In a mixture of non-reacting gasses, the total pressure exerted is equal to the sum of the partial pressures
64
Boyle's law
the volume of a container and the pressure within that container are inverseley related
65
Henry's law
The amount of gas dissolved in a liquid is directly proportional to the pp of that gas in its gas phase.
i.e. solubility is directly proportional to pp
66
The alveolar gas equation
this allows the calculation of alveolar pp of Oxygen (PAO2) by using data that is measurable
It assumes that the alveolar and the arterial pp of CO2 is equal
R is the respiratory quotient which is the ration of the volume of CO2 evolved from the quantity of oxygen consumed. Use 0.8
PAO2 = PiO2 - PaCO2/R
67
Laplace's law
transpulmonary pressure is **directly** **proportioonal** to the surface tension and **inversely proportional** to the radius
P = 2T/r
P is the transpulmonary pressure required to oppose recoil
T is the surface tension
This is how surfactant works - by reducing T and therefore reducing the pressure needed to overcome recoil
68
How is CO2 transported in the blood
* 10% dissolved in plasma
* 30% transported in from carbaminohaemoglobin
* 60% carried as HCO3- ions
69
Sources of H+ in the body
* Dissociatin of carbonic acid
* From metabolic products like Lactic acid
70
What is the main drive to breathe?
Hypercapnia
71
What is hypoxia and what are the 4 types?
* Deficiency of oxygen at the tissue level
* 4 types
* Hypoxaemia
* Anaemia or CO hypoxia
* Ischaemic hypoxia
* Histotoxic hypoxia
72
Type 1 respiratory failure
* Hypoxia and hypoxaemia but no hypercapnia
* Caused by problems with oxygenation:
* High altitude
* V/Q mismatch
* Asthma
* Pneumonia
73
Type 2 respiratory failure
* Both hypercapnia and hypoxia
* Caused by poor ventilation:
* COPD
* Obesity
* Decreased vital capacity
74
Name each of these arrows
75
draw the flow volume curve including:
* PEF
* FEV1
* FEF25, 50 and 75
76
Airway obstruction
* Blockage of airways
* COPD, asthma, cystic fibrosis
* FEV1/FVC has tobe less than 0.7
* FVC is normal
77
Airway restriction
* Decreased ability to expand
* Pulmonary fibrosis, sarcoid
* Normal FEV1/FVC ratio (both will be reduced but proportionally)
* FVC is reduced below 80% of expected
78
Two arterial circulations of the lungs
* Pulmonary circulation
* 100% of blood from right ventricle
* Thin walled vessels
* Lower blood pressure
* Bronchial circulation
* 2% of the output from the left ventricle
* Thicker walls with significant muscle
* systemic blood pressure
79
what is mPAP
* mean pulmonary arterial pressure
80
key changes of an aging lung
* Chest wall stiffer and less compliant
* Muscles are weaker
* Lung loses elastin recoil
* Impaired gas exchange
* Impaired immune system
* Vital capacity decreases
81
draw the oxygen dissociation curve and state what shifts it and in which direction
82
Gell and coombs table - include the relevant antibodies and a brief explanation of each. Give example of presentation
* Mnemonics
* ACID
* Allergic, Cytotoxic, Immune complex, Delayed
* AnGST
* Anaphylaxis, Goodpastures, Sarcoid, TB
83
Parasympathetic control of airway tone
* This is a **direct effect**
* Ach acts on M3 cholinergic receptors in smooth muscle leading to bronchoconstriction
84
Sympathetic control of airway tone
* Noradrenaline released by SNS stimulates release of adrenaline from the adrenal glands
* Adrenaline acts on B2 adrenergic receptors in the lungs and causes bronchodilation
* This is an **indirect effect**
85
6 steps of coughing
1. air inspired
2. epiglottis and vocal cords close
3. abdominal and internal intercostal muscles contract forcefully
4. intrathoracic pressure increases
5. epiglottis and vocal cords open widely
6. air is suddenly expired
86
What's V'A
Alveolar ventilation
87
Whats V'CO2
CO2 production
88
Altitude and the lungs
* PiO2 falls with increasing altitude
* Alveolar gas equation:
* PAO2 = PiO2 - PCO2/0.8
* Therefore Alveolar O2 drops
* Hypoxia leads to:
* hyperventilation --\> alkalosis
* eventually, in chronic respiratory alkalosis, renal bicarbonate would compensate
89
Infrahyoid Muscles: label this diagram
90
What are the inferior borders of the lung
* Mid clavicular: rib 6
* Mid axillary: rib 8
* Back: rib 10
91
where does the apex of the lung extend to?
3cm above the medial 3rd of the clavicle
92
Inferior borders of the pleura
* Mid clavicular: rib 8
* Mid axillary: rib 10
* Back: rib 12
93
rib level of the oblique fissures
* Mid clavicular: 6
* Mid axillary: 4
* Back: 2
94
Rib level of the horizontal fissure
It tracks the 4th intercostal space (just below the 4th rib)
NB right lung only
95
Rules for the hilum of the lungs
* On both sides
* Bronchus is posterior
* Pulmonary veins are anterior and inferior
* On the right
* Artery is anterior to the bronchus
* On the left
* Artery is the most superior structure
96
at what vertebral level do the IVC, Oesophagus and Aorta pass through the diaphragm?
I 8 10 Omletes At 12
* IVC: 8
* Oesophagus: 10
* Aorta: 12
97
* Alveoli
* Simple squamous
* 90% SA: Type I pneumocytes
* 10% SA: Type II pneumocytes
98
Expiration
1. Phrenic stops firing motor signals to the diaphragm
2. Diaphragm ascends
3. Thoracic cavity volume decreases
4. Intrapleural pressure increases
5. This causes transpulmonary pressure to become less
6. Transpulmonary pressure becomes less than the power of the elastic recoil of the lungs
7. Lungs passively collapse, increasing pressure in alveoli
8. When this exceeds the atmospheric pressure there is outward air flow
99
what is normal tidal volume
500ml (air inhaled/exhaled in normal breathing)
100
What is a normal Inspiratory reserve volume
3000ml (amount of air that can be inspired over and above tidal inspiration, with maximal effort)
101
What is a norma expiratory reserve volume
1200ml (amount of air exceeding tidal expiration that can be exhaled with maximal effort)
102
What is a normal residual volume
1200ml (this is the amount of air that remains in the lungs following maximal exhalation and functions to keep the alveoli inflated)
103
what is a normal vital capacity
4700ml (amount of air that can be exhaled following with maximal effort following maximal inhalation)
104
What is a normal inspiratory capacity
3500ml (maximum amount of air that can be inhaled after a normal tidal expiration)
105
What is normal functional residual capacity
2400ml (the amount of air remaining in the lungs after normal tiday expiration)
106
what is normal total lung capacity
5900ml (Maximum amount of air that the lungs can contain)
107
4 important elements of the host defences in the lungs
* Alveolar macrophages
* Muco-ciliary escalator
* Epithelial barrier - moistens and protects is also physical barrier to pathogens
* Coughing
108
6 effects of first breath:
1. contractions squeeze fluid out of the lungs
2. adrenaline surge causes a surfactant release
3. lungs expand
4. O2 vasodilates pulmonary arteries and arterioles
* causes pressure drop in right side of heart
5. O2 constricts umbilical artery and ductus arteriosus
6. Lower pressure in right side of heart and high pressure on left side causes foramen ovale to snap shut
* lid snaps up from left side this is why it is visalbe from right but not left atrium
NB: ductus venosus remains open for a time but will close within the first week of life
109
What the remnants of the foetal circulation become
* Foramen ovale --\> fossa ovalis
* Ductus arteriosus --\> ligamentum arteriosum
* Ductus venosus --\> ligamentum venosum
* Umbilical Vein --\> ligamentum teres
110
From how many weeks is surfactant produced
24 weeks
very prem babies may be deficient in surfactant
111
how could you measure residual volume and therefore total lung capacity
Gas dilution or body box
TLC = VC+RV
112
what would be abnormal FEV1 or FVC
anything below 80% of the expected value
113
why is the oxygen dissociation curve sigmoid
becauase sequential binding of O2 to Hb requires less energy
114
what is the bohr effect
increased H+ concentration shifts the oxygen dissociation curve to the right
this is because higher H+ ion concentrations cause Hb to have a lower affinity for oxygen
this allows oxygen to be easily deposeted in highly metabolically active tissues which may be more acidic
115
Normal blood gasses at sea level
* PaO2 **=** 10.5 – 13.5 kPa
* PaCO2 = 4.5 – 6.0 kPa
* pH = 7.36 – 7.44
116
Volume of Lung capacity when diving
* Every 10m the pressure increases by 1atm
* But at sea level you start from 1atm
* So at 70m depth it's 8atm
* So using boyle's law (P1V1 = P2V2):
* A diver who had a TLC of 8L at the surface would have a TLC of 0.47L at 160m depth
* 1x8=17x0.47
117
Why do people get the bends?
Henry's law: at higher pressure more gas dissolves into the bodies tissues
if you ascend at a rate that exceeds the bodies ability to clear the gas then bubbles will form in tissues
this can be fatal
118
Embryological origins of the lungs
Endoderm: epithelia
Splanchnic mesoderm: cartilage, muscle and connective tissue
119
at what week do the lung buds form?
4th week
120
at what week do the bronchi form?
5th week
121
what is this and what is the stain
what's in the middle, what's on either side and what is the blue stuff
Nasal septum stained with HE and Alician Blue
* Central plate of bone
* Respiratory epithelia on either edge
* connective tissues connect epithelia and the bone
* Swell bodies (blood vessels) contained within this connective tissue
* Blue blobs are mucus secreting goblet cells
122
What is this, what stain was used, what epithelium is it. What are the blue things.
* Olfactory epithelium stained with HE and Alician Blue
* Pseudostratified columnar epithelium
* immotile sterocilia at the surface
* Blue things under epithelium are serous glands that flush away old smells
* there are also large oval nerve fibre bundles in transverse section
123
What epithelia lines the larynx
* the larynx is lined by respiratory epithelium
* except for the vocal folds that are covered by a stratified squamous epithelium
* vocal folds have to be robust
124
What is this, what is the epithelium, what's at the bottom
* This is the trachea stained with HE
* Cartilage at teh bottom
* Epithelium is pseudostratified ciliated columnar
* respiratory epithelium
* You can also see serous glands that discharge mucous onto the surface
125
What is this, what underlies the epithelium and what's the purple thing at the bottom
* This is a bronchus stained with HE
* pseudostratified cilliated epithelium
* respiratory epithelium
* There's a thin band of smooth muscle just underneith the epithelium
* I think the purple thing at the bottom is a 'supporting plate of hyaline cartilage'
126
What is this, what is the epithelium and what surrounds it
* this is a bronchiole
* it is a simple ciliated epithelium
* respiratory epithelium
* smooth muscle just under epithelium
* Differences with bronchi
* Bronchioles have no cartilage in their walls
* Their band of smooth muscle is a bit more prominant
* This means they can be constricted by the smooth muscle
127
What is this, what is the epithelium
* this is a terminal bronchiole (bottom right) turning into a respiratory bronchiole top left
* simple cuboidal epithelium
* the smooth muscle regulates ventilation of alveoli distal to it
128
What do fibroblasts in the alveoli produce
* reticulin (collagen III)
* elastic tissue
129
What is this and what are the black dots
Alveoli
* flattened capillary endothelial cells and type I pneumocytes are sandwiched together to form an air blood barrier that is 0.6microns wide
* Black dots are alveolar macrophages that have engulfed carbon particles
130
describe a typical rib and how it attaches to the vertebrae
* head
* two articulatory facets
* one with the corresponding vertebra and one with the vertebra above
* Neck
* nondescript but where it joins the shaft there is the tubercle which articulates with the transverse porocess of the corresponding vertebra
* Body
* has a groove on inferior interior surface for the intercostal artery vein and nerve to run
131
Rib classifications
* 1-7 are true ribs
* their costal cartilages attach directly to the sternum
* 8-12 are false ribs
* their costal cartilages do not attach directly to the sternum
* 8-10 attach to the cc of the rib above
* 10-12 are floating ribs
* their costal cartilages do not attach to the sternum at all
132
how much oxygen and nitrogen is there in dry air? percentages
Oxygen: 21%
Nitrogen: 78%
Other: 2%
EM:
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