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Phase 1 M > Respiratory > Flashcards

Respiratory Flashcards

1
Q

What are the functions of the nose?

A

Temperature of inspired air
Humidity (75-80%)
Filter function
Defence (Cilia take inhaled particulates

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2
Q

Where do the anterior nares (nostrils) open into?

A

vestibule

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3
Q

How is the surface area of the nose increased?

A

Turbinates (rounded shelves)

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4
Q

What are the three types of meatus?

A

Superior
Middle
Inferior

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5
Q

Describe the properties of the superior meatus

A

Has olfactory epithelium
Olfactory nerve penetrates through superior meatus via pores in the cribriform plate
Sphenoid sinus drains here

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6
Q

Describe the properties oft the middle meatus

A

Sinuses drain here

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7
Q

Describe the properties of the inferior meatus

A

Nasolacrimal duct drains here

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8
Q

Define what the paranasal sinuses are?

A

Pneumatised areas (Bone that is hollow or contains air cells) of the frontal, ethmoid,. sphenoid and maxillary bones that are arranged in pairs

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9
Q

Draw a diagram to show the location of the paranasal sinuses

A

See diagrams I should know

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10
Q

Describe the location and the innervation of the frontal sinus

A

Located within in the frontal bone and lies above the orbit

Innervated by the ophthalmic division (V1) of the trigeminal nerve

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11
Q

Describe the location of the maxillary sinus

A

Located within the body of the maxilla where the base is the lateral wall of the nose, roof is the floor of the orbit, apex is the zygomatic process of the maxilla and floor is the alveolar process (Pyramidal shape)
Opens into the middle meatus

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12
Q

What is the innervation of the maxillary sinus

A

Maxillary division (V2) of the trigeminal nerve

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13
Q

Describe the location and the innervation of the ethmoid sinus

A

Between the eyes and is a labyrinth of air cells
Semilunar hiatus of middle meatus
Innervation by the ophthalmic and maxillary branches of trigeminal nerve

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14
Q

Describe the location of the sphenoid sinuses

A

Medial to the carvenous sinus (which contains internal carotid artery, oculomotor nerve, trochlear, trigeminal and abducens
Inferior to optic canal, dura and pituitary gland
Empties into sphenoethmoidal recess lateral to the attachment of the nasal septum

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15
Q

What is the innervation of the sphenoid sinus

A

Ophthalmic division off the trigeminal nerve

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16
Q

What epithelium lines the pharynx

A

Squamous and columnar ciliated epithelium with mucus glands

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17
Q

Where does the pharynx extend from and what parts does it consist of?

A

Fibromuscular tube running from the skull base to C6 where it becomes continuous with the oesophagus
consists of nasopharynx, oropharynx and laryngopharynx

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18
Q

What Is the function of the larynx?

A

Valvular function which prevents liquids and foods from entering the lung

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19
Q

Describe the cartilaginous structure of the larynx

A 
Consists of 9 cartilages 
3 paired (Cuneiform, corniculate and arytenoid)
3 unpaired (Epiglottis, thyroid, cricoid
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20
Q

What two larynx cartilages interact to change the vocal cords?

A

Arytenoid cartilages rotate on the cricoid cartilages

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21
Q

Where would you carry out a tracheotomy?

A

Cricothyroid membrane

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22
Q

Which nerves innervate the larynx

A

Vagus Nerve

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23
Q

What does the the recurrent laryngeal nerve innervate

A

All the motor innervation for all laryngeal muscles except cricothyroid

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24
Q

What does the superior laryngeal nerve innervate

A

Divides into internal (for sensation to larynx) and external (motor innervation to cricothyroid muscle)

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25
Q

Describe the pathway of the left recurrent laryngeal nerve

A

Runs laterally to the arch of the aorta, loops under the aortic arch then ascends between the trachea and the oesophagus

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26
Q

Describe the pathway of the right recurrent laryngeal nerve

A

Loops under the right subclavian artery and runs up in the plane between the trachea and the oesophagus

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27
Q

What symptom would ulcers/tumours on or near the pathway of the recurrent laryngeal nerve cause?

A

Hoarse voice

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28
Q

What is the function of the lower respiratory tract?

A

Gas exchange

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29
Q

Define and give an approximation of minute ventilation

A

Volume of air inhaled/exhaled in a minute (approx 5 litres)

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30
Q

Describe the structure of the trachea

A

From larynx to carina (C6-T5) - oval in cross section
Contains semi-circular (C-shaped)(absent posteriorly) hyaline cartilages connected by tracheal muscle that increases flexibility

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31
Q

What epithelium lines the trachea

A

Pseudo-stratified ciliated columnar epithelium with goblet cells

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32
Q

The carina lies at what spinal level?

A

T5

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33
Q

Describe the structure of the main bronchus

A

Left and right main bronchus divided by the carina
right main bronchus is more vertically disposed (1-2.5cm long (related to pulmonary artery)
Left main bronchus is longer (5cm) and less vertical (Related to aortic arch)

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34
Q

Which main bronchus is a peanut more likely to get stuck in

A

Right main bronchus because the right is more vertically disposed and shorter

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35
Q

What does the right lobar bronchi consist of

A

Upper lobe
Middle lobe
Lower lobe

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36
Q

What does the left lobar bronchi consist of?

A

Upper lobe and lingual

Lower lobe

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37
Q

How many segmental branches on the right are there

A

10

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38
Q

How many segmental branches on the left are there

A

8

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39
Q

Describe the pathway of the trachea and the bronchioles

A

Trachea, L/R main bronchus, Lobar bronchia, segmental bronchia, terminal bronchioles, respiratory bronchioles, alveolar ducts and finally alveoli

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40
Q

What are interconnections between alveoli known as

A

Pores of Kohn

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41
Q

Define acinus

A

Tissue supplied with air by one terminal bronchiole

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42
Q

What are the constituents of alveoli

A 
Type I pneumocytes 
Type II Pneumocytes (Secrete surfactant)
Alveolar macrophage 
Basement membrane 
Interstitial tissue 
capillary endothelial cells
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43
Q

Describe the innervation of the lungs

A

Pulmonary plexus lies behind each hilum - receives innervation from vagus nerves and T2-4 of sympathetic trunk

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44
Q

Sympathetic innervation of the lung results in

A

Bronchodilation

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45
Q

Parasympathetic innervation of the lung results in

A

Bronchoconstriction

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46
Q

Describe the pleura of the lungs

A

2 layers of mesodermal origin
Visceral-lung surface - only has autonomic innervation
Parietal - internal chest - has pain sensation via phrenic nerve
Small amount of fluid in between

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47
Q

Describe the blood supply of the lung

A

Bronchial and pulmonary
L/R pulmonary run to right ventricle and have 17 orders of branching
Bronchus and pulmonary arteries run together via the bronchovascular bundle

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48
Q

Define transpulmonary pressure

A

Difference in pressure between the inside and outside of the lung (Alveolar pressure - intrapleural pressure)

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49
Q

Define intrapleural pressure

A

Pressure inside the pleural space - intrathoracic pressure

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50
Q

Define alveolar pressure

A

Air pressure in pulmonary alveoli

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51
Q

What are the muscles of inspiration

A

Quiet breathing and diaphragm (C3/4/5)

External intercostals

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52
Q

What are the muscles of expiration

A

Passive process due to quiet breathing

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53
Q

Describe the process of inspiration

A

External intercostal muscles and diaphragm due to phrenic nerve from C3/4/5.

  1. Diaphragm contracts causing the dome to move downwards, thereby enlarging the thorax (Increased volume)
  2. Simultaneously, activation of motor neurones in the intercostal nerves to the external intercostal muscles causes them to contract resulting in upward and outward movement of ribs further increasing volume
  3. As thorax expands, intrapleural pressure is lowered and transpulmonary pressure becomes more positive resulting in lung expansion as force causing lung expansion is greater than elastic recoil
  4. Lung expansion causes alveolar pressure to become more negative
  5. Causes inward flow of air
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54
Q

Describe the process of expiration during quiet breathing

A
  1. motor neurones to intercostal nerves and diaphragm decrease firing so muscles relax and diaphragm ascends thus decreasing thoracic volume
  2. As they relax, lungs and chest walls collapse passively due to elastic recoil as intrapleural pressure increases causing transpulmonary presure to decrease below elastic recoil pressure
  3. As lungs become smaller the air in the alveoli becomes compressed resulting in an increase in external intercostal pressure above atmospheric pressure so air flows outwards
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55
Q

Describe the process of forced expiration that occurs during exercise

A
  1. On top of passive expiration the internal intercostal muscles and abdominal muscles (rectus abdominus and external abdominal obliques) contract
  2. This causes the ribs to move downwards and inwards, actively decreasing thoracic volume. Abdominal muscle contraction causes further increase in intra-abdominal pressure forcing the diaphragm further into the thorax further decreasing thoracic volume
  3. Results in greater than normal volume of air being expired
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56
Q

What is the airway of greatest resistance?

A

The trachea because it has a smaller surface area than all the bronchioles combined meaning it provides the greatest resistance

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57
Q

Define dead space

A

Volume of air not contributing to ventilation

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58
Q

What is the volume of the physiological dead space?

A

175mls in total in the lungs

150mls anatomically and 25mls in alveoli

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59
Q

Where does gas exchange occur?

A

Between the alveoli and the capillaries

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60
Q

How many layers must O2 diffuse through to cross from alveoli to the capillaries

A

7 layers

  1. Alveolar epithelium
  2. Tissue interstitium
  3. Capillary endothelium
  4. Plasma layer
  5. Red cell membrane
  6. Red cell cytoplasms
  7. Hb binding
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61
Q

What is required for each alveolus to be as efficient as possible?

A

The correct proportion of alveolar air Flow (ventilation) and capillary blood flow (perfusion) - any mismatch is called ventilation perfusion inequality

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62
Q

What is the main effect of a ventilation perfusion mismatch?

A

Decreased partial pressure of O2 in the systemic blood

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63
Q

Describe ventilation perfusion inequality in healthy individuals

A

inequality enough to reduce the arterial Po2 by 5mmHg due to gravitational effects as in upright position there is increased filling of blood vessels at the bottom of the lung which contributes to differences in blood-flow distribution so on average PO2 in alveoli is 5mmHg higher than in partial blood

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64
Q

What consequences of disease can cause a ventilation perfusion mismatch?

A

Regional changes in compliance, airway resistance and vascular resistance

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65
Q

What are the two extremes of ventilation perfusion mismatch?

A

Ventilated alveoli with no blood supply due to blood clot or adequate blood flow through the lung but no ventilation due to collapsed alveoli

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66
Q

Describe what happens during local homeostatic hypoxic pulmonary constriction?

A

Decrease in ventilation in alveoli leads to decrease in alveolar PO2 and in surrounding blood vessels. This decrease in PO2 leads to vasoconstriction to deliver the blood away from poorly ventilated areas - unique to pulmonary arterial vessels

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67
Q

What is PaCO2

A

Arterial Co2

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68
Q

What is PACO2

A

Alveolar Co2

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69
Q

What is PaO2

A

Arterial O2

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70
Q

What is PAO2

A

Alveolar O2

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71
Q

What is PIO2

A

Pressure of inspired O2

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72
Q

What is VA

A

Alveolar ventilation

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73
Q

What is VCO2

A

CO2 production

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74
Q

What is the structure of the haemoglobin molecule?

A

Four subunits (globin) with each subunit containing a heme group which contains an Iron atom to which oxygen can bind

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75
Q

How many molecules of oxygen can a single Hb molecule bind?

A

4

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76
Q

What are the two forms that Hb can exist as?

A

Oxyhaemoglobin

Deoxyhaemoglobin

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77
Q

What is the value of systemic arterial PO2

A

100mmHg

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78
Q

What is the value of systemic venous PO2

A

40mmHg

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79
Q

Describe the oxygen dissociation curve

A

As PO2 increases the HB saturation will increase rapidly so that Hb saturation is at 90% at PO2 of 60mmHg. After this point, increases in PO2 will cause a small increase in Hb saturation

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80
Q

How many lobes does the right lobar bronchi have?

A

3

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81
Q

What are the 3 lobes of the right lobar bronchi?

A

Upper
Middle
Lower

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82
Q

How many physical lobes does the right lung have?

A

3

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83
Q

How many lobes does the left lung have?

A

2

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84
Q

What 3 qualities are required for efficient gas exchange to occur?

A

Large surface area
Minimal diffusion distance
Adequate perfusion

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85
Q

Describe what happens during local bronchoconstriction

A

Decrease blood flow in region means less systemic CO2 which means reduced PCO2 so bronchoconstriction occurs to divert airflow to areas with better perfusion

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86
Q

What does a shift in the oxygen dissociation curve to the left mean?

A

Hb has more affinity for oxygen

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87
Q

What does a shift in the oxygen dissociation curve to the right mean?

A

Hb has less affinity for oxygen

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88
Q

An increase in temperature will shift the oxygen dissociation curve in what direction

A

To the right

89
Q

A decease in pH will shift the oxygen dissociation curve in what direction?

A

To the right

90
Q

What are the effects of carbon monoxide on the oxygen dissociation curve?

A

CO has 200x greater affinity for Hb than O2 does so reduces the amount of O2 that binds with Hb and reduces Hb affinity for O2. CO therefore shifts curve to the left, decreasing O2 unloading in tissues

91
Q

What are the three ways that CO2 Is carried in the blood?

A
  1. Bound to Hb as carbaminohaemoglobin
  2. Dissolved in plasma
  3. As bicarbonate
92
Q

What percentage of Co2 is transported I the blood as carbaminhaemoglobin?

A

23%

93
Q

What percentage of CO2 is transported in the blood dissolved in the plasma?

A

10%

94
Q

What percentage of CO2 is transported in the blood as HCO3- ions?

A

60-65%

95
Q

Why does CO2 diffuse from the blood into alveoli?

A

Because the blood PPCO2 is greater than the alveolar PPCO2

96
Q

What is normal blood pH?

A

7.35-7.45

97
Q

What are the three main buffering systems for acid/base?

A

Intra/extracellular buffers, lungs eliminating CO2

Renal HCO3- reabsorption and H+ elimination

98
Q

What is the equation for the bicarbonate buffer system?

A

CO2 + H20 –> H2CO3 –> HCO3- + H+

99
Q

Describe how a respiratory acidosis occurs

A

When someone hyperventilates there is inadequate ventilation of the alveoli meaning CO2 is not excreted so their PCO2 increases resulting in more carbonic acid being produced which dissociates to increase the H+ concentration in the blood = respiratory acidosis

100
Q

Describe how a respiratory alkalosis occurs?

A

Hyperventilation causes CO2 to be blown off quickly which reduces the arterial partial pressure of CO2, reducing the formation of H2CO3 and H+ formation leading to.a respiratory alkalosis

101
Q

What is the equation for Henderson Hasselbalch

A

pH = 6.1 + Log ([HCO3-]/(0.03 * PCO2))

102
Q

What is Dalton’s law

A

Pressure exerted by each gas in a mixture is independent of the pressure exerted by other gases so the total pressure of the mixture is a sum of the individual pressures which are directly proportional to concentration

103
Q

What is Boyle’s Law?

A

The pressure of a fixed amount of gas is inversely proportional to the containers volume

104
Q

What is Henry’s Law?

A

Amount of gas dissolved in a liquid is proportional to the partial pressure of the gas with which the liquid is in equilibrium

105
Q

What is the alveolar gas equation?

A 
PAO2 = PiO2 - PaCO2/R 
(R = respiration exchange ratio = ratio between amount of CO2 produced in metabolism and oxygen used)
106
Q

What is the Law of Laplace?

A

Relationship between pressure (P), surface tension (T) and radius of an alveolus (R) = P=2T/r

107
Q

What is lung compliance?

A

Change in lung volume caused by a given change in transpulmonary pressure ie. greater the lung compliance the more readily the lungs expand

108
Q

What is surface tension

A

Attractive forces between water molecules at the air-water interface in alveoli

109
Q

What forces do the lungs need to overcome to expand?

A

Surface tension of the water lining the alveoli

Stretch the connective tissue

110
Q

How do the lungs overcome the forces that resist expansion

A

Type II pneumocytes secrete surfactant which reduces the cohesive forces between water molecules which lowers surface tension and increases lung compliance making it easier for the lungs to expand

111
Q

When does the level of surfactant decrease

A

When individuals take take small and constant breaths

112
Q

Define Inspiratory reserve volume?

A

Amount of air in excess tidal inspiration that can be inhaled with maximum effort

113
Q

Define Expiratory reserve volume?

A

Amount of air in excess tidal expiration that can be exhaled with maximum effort

114
Q

Define residual volume

A

The amount of air remaining in the lungs after maximum expiration

115
Q

Define vital capacity

A

The amount of air that can be exhaled with maximum effort after a maximum inspiration (ERV + TV + IRV)

116
Q

Define functional residual capacity

A

Amount of air remaining in the lungs after a normal tidal expiration (RV+ ERV)

117
Q

Define inspiration capacity (IC)

A

Maximum amount of air that can be inhaled after a tidal expiration (TV + IRV)

118
Q

Define Total lung capacity

A

Maximum amount of air the lungs can contain (RV + VC)

119
Q

Define tidal volume

A

Amount of air inhaled or exhaled in one breath

120
Q

What is a normal tidal volume?

A

500ml

121
Q

Define FEV1

A

Forced expiratory volume in 1 second

122
Q

What is a normal FEV1 value for a healthy individual

A

80% of their vital capacity in one second

123
Q

What does an FEV1 value of 80% or greater suggest

A

Lung health is normal

124
Q

What does an FEV1 value of less than 80% of the predicted value suggest

A

Lung health is abnormal

125
Q

What does a low FVC value suggest

A

Airway restriction

126
Q

What does an FEV1/FVC ratio of below 0.7 suggest

A

Airway obstruction

127
Q

What does a normal FEV1/FVC ratio but low FEV1 value suggest?

A

Airway restriction

128
Q

What are of the brain is responsible for the control of breathing?

A

Medulla oblongata

129
Q

What are the two main anatomical components of the medulla oblongata that are important for breathing

A

Dorsal respiratory group

Ventral respiratory group

130
Q

What are the two main anatomical components of the medulla oblongata that are important for breathing

A

Dorsal respiratory group

Ventral respiratory group

131
Q

When do the neurone s of the DRG primarily fire and what do they activate?

A

Fire during inspiration and activate the diaphragm and external intercostal muscles

132
Q

Where is the respiratory rhythm generator located

A

In the pre-Botzinger complex in the upper part of the DRG

133
Q

When do they neurones of the VRG fire and what do they activate

A

Expiratory neurones of the VRG activated when large increases in ventilation are required such as during strenuous exercise by causing expiratory muscles to contract
Also has some inspiratory neurones

134
Q

When is the DRG active

A

inspiration

135
Q

when is the VRG active

A

Inspiration and expiration

136
Q

Which respiratory control neurones are found in the pons

A

Pneumotaxic centre

Apneustic centre

137
Q

What is the function of the Pneumotaxic centre?

A

Inhibits the apneustic centre and promotes expiration

Increased output here = shallower more frequent breaths raising respiratory rate but reducing inspiratory volume

138
Q

What is the function of the apneustic centre

A

Stimulates the DRG

Increases the intensity of inhalation but is quickly inhibited by the pneumotaxic centre

139
Q

What is the function of the DRG

A

Contains inspiratory neurones

Involved in quiet and forced breathing

Innervates the external intercostal muscles and diaphragm to cause inhalation

Passive exhalation occurs on signal cessation

140
Q

What is the function of the VRG

A

Contains inspiratory and expiratory neurones

Forced breathing

Stimulated by DRG activating muscles of inhalation then the expiratory neurones of VRG stimulate the accessory muscles exhalation

141
Q

Describe slowly adapting pulmonary stretch receptors?

A

Found in airway smooth muscle

Activated by lung distension

High activity inhibits further inspiration beginning expiration

142
Q

Describe rapidly adapting stretch receptors

A

Found between airway epithelial cells

Activated by lung distension and irritants

Produce brief burst of activity

high activity causes bronchoconstriction - cough reflex

143
Q

Describe C fibres and J receptors

A

Found in capillary walls and interstitium

Stimulated by an increase in lung interstitial pressure caused by collection of fluid in the interstitium

Activity causes rapid breathing, shallow breathing, bronchoconstriction, CV depression and dry cough

J receptors give sensations of pressure in chest and dyspnea

144
Q

Where are the peripheral chemoreceptors located

A

Common carotid bodies - bifurcation of the common carotid artery
Aortic bodies - Arch of the aorta

145
Q

What are the peripheral chemoreceptors sensitive to?

A

An increase in arterial H+ concentration

A decrease in PaO2

146
Q

Which CN afferents take information from the common carotid bodies

A

Glossopharyngeal

147
Q

Which cranial nerve afferents take information from the aortic bodies

A

Vagus Nerve

148
Q

What are peripheral chemoreceptors not activated until PaO2 drops to 60mmHg

A

peripheral chemoreceptors not sensitive to small reductions in PaO2 because at 60mmHg Hb saturation is still 90% so it is not until below 60mmHg that oxygen transport of the blood falls thus increasing ventilation to add more O2 to the blood is pointless until that point is reached

149
Q

Where are the central chemoreceptors located

A

In the medulla of the brainstem

150
Q

What are the central chemoreceptors sensitive to?

A

Stimulated to increased H+ conc in CSF but BBB is impermeable to H+ so blood PCO2 which diffuses across the BBB influences pH CSF
Ventilatory drive is extremely sensitive to changes in arterial PCO2

151
Q

Central chemoreceptors account for what percentage increase in ventilatory rate

A

70%

152
Q

Define hypoxia

A

Deficiency of oxygen at tissue level

153
Q

What is the most common type of hypoxia?

A

Hypoxemia = reduced PaO2

154
Q

What are the four most common causes of hypoxia?

A
  1. Hypoventilation causing increased PaCO2 and failure to adequately ventilate alveoli
  2. Diffusion impairment resulting from thickening of alveolar membrane or decrease in surface area
  3. Shunting - anatomical CVS abnormality that causes mixed venous blood to bypass the ventilated alveoli
  4. ventilation perfusion mismatch which is caused by COPD where the PaCO2 may be normal or increase
155
Q

Define hypercapnia

A

CO2 retention leading to an increased PaCO2

156
Q

What is the main cause of hypercapnia

A

Hypoventilation

157
Q

What happens to CO2 and O2 in Type 1 respiratory failure

A

PO2 is low

PCO2 is low or normal

158
Q

What is the main cause of Type 1 respiratory failure

A

pulmonary embolism

159
Q

What happens to Co2 and O2 in type 2 respiratory failure

A

PO2 is low

PCO2 is high

160
Q

What is the main cause of type 2 respiratory failure

A

Hypoventilation

161
Q

What are the two circulations to the lung

A

Pulmonary circulation

Bronchial circulation

162
Q

Parasympathetic nervous system innervates the lung via what nerve

A

vagus

163
Q

What neurotransmitter does the parasympathetic nervous system supplying the lung use and to what receptor does it bind

A

ACh

Muscarinic M3

164
Q

The parasympathetic nervous system governs what property of the airways

A

Their intrinsic tone

165
Q

What will too much parasympathetic innervation of the lung cause

A

BronchoCONSTRICTION

166
Q

What are the effects of the sympathetic nervous system on the lung

A

Cause the release of noradrenaline which causes release of adrenaline from the adrenal gland which binds B2 adrenoreceptors causing bronchoDILATION

167
Q

Describe the intracellular casacade when ACh binds to M3 receptors

A

Activates the Gq protein
Activates PLC
PLC breaks down PM phospholipid into DAG and IPC
DAG acts s second messenger to activate PKC
IP3 binds ligand gated Ca2+ channels on endoplasmic recticumulum causing them to open, releasing Ca2+ which stimulates bronchoCONSTRICTION

168
Q

Describe the intracellular cascade when adrenaline or noradrenaline binds to Beta 2 receptors

A

Activates Gs protein
Activates Adenyl cyclase which converts ATP to cAMP which acts as a second messenger to decrease calcium concentrations and activate PKA causing BRONCHODILATION

169
Q

What types of drugs are given to alleviate asthma and COPD

A

Bronchodilators
Muscarinic antagonists
beta-2 agonists

170
Q

Name 2 short acting beta-2-agonists

A

Salbutamol and terbutaline

171
Q

Name 2 long acting beta-2-agonists

A

Salmeterol and formoterol

172
Q

Name a short acting muscarinic antagonists

A

Ipratropium

173
Q

Name a long acting muscarininc antagonis t

A

Tiotropium

174
Q

How does the ciliated pseudo stratified columnar epithelium of the lung provide protection

A

Moistens and protects airways
Barrier to pathogens
Mucociliary escalator
Mucus secreted is sticky so particles adhere to it and are phagocytosis by macrophages

175
Q

Define a cough

A

Explosive expiration that provides a normal protective mechanism for clearing tracheobrachial secretion and foreign material
either initiated voluntarily or reflexively

176
Q

Where are the receptors for the cough reflex located

A

Larynx
trachea
bronchi

177
Q

Which immune cells are phagocytes?

A

Neutrophils and phagocytes

178
Q

Name the 4 chemical epithelial barriers

A

Antiproteinases
Anti-fungal peptides
Anti-microbial peptides
Surfactant A and D

179
Q

Why can damage to the airway epithelium following an infection be resolved?

A

because the epithelium demonstrates functional plasticity but when this goes wrong a pulmonary disease might occur

180
Q

What is the pathophysiology of COPD

A

Unresolving neutrophilic inflammation release proteases that cause breakdown of the lung walls reducing alveolar function

181
Q

What are the 6 functions of neutrophils?

A
  1. Identify threat receptors (Bacterial structures, host mediators, host opsonins)
  2. Activation
  3. Adhesion
  4. Migration
  5. Phagocytosis
  6. Bacterial killing
182
Q

How does the lung defend itself against pathogens

A

Innate mechanisms

Adaptive mechanisms

183
Q

What are the external defences of the innate immunity

A

Skin
Mucous membranes
Secretions

184
Q

What are the internal defences of the innate immunity

A

Phagocytic cells
Antimicrobial proteins
Inflammatory response
natural killer cells

185
Q

What are the acquired immunity defences

A 
Humoral response (Antibodies)
Cell mediated response (Cytotoxic lymphocytes)
186
Q

Which cells act as antigen present cells

A

Alveolar macrophages and dendritic cells

187
Q

What are the two types of lymphocyte

A 
T cells (Cytotoxic T cells and T helper cells) 
B cells = produce antibodies
188
Q

What is an antigen

A

A molecule capable of inducing an adaptive immune response

189
Q

What are the 3 key properties of the adaptive immune system

A

Diversity
Self tolerance
immunological memory

190
Q

Define humeral immunity

A 
things that are in the blood but not cells
 - immunoglobulins 
Complement 
Surfactant proteins 
Cytokines
191
Q

Define the innate immunity

A

Immediate response to foreign pathogen that does not require previous exposure and mainly involves the phagocytosis of Bacteria and rapid responses to viruses

192
Q

How do alveolar macrophages respond to pathogens or tissues?

A

Recognise PAMPs (Pathogen associated molecular patterns)
Recognise DAMPS
(Damage associated molecular patterns)

193
Q

How do alveolar macrophages recognise new pathogens

A

Pattern recognition receptors - part of innate immunity that recognise common antigens on bacteria such as Toll like receptors

194
Q

What do the primary granules of neutrophils contain

A

Myeloperoxidase
Elastate - breaks down elastin in lungs to enable neutrophil to migrate through to get to pathogen
Capthesin and defensin (Antibacterial proteins)

195
Q

What do the secondary granules of neutrophils contain?

A

Lysozyme - breaks down bacteria cell walls

Collagenase - breaks down collagen allowing neutrophils to penetrate hard to reach collagenised areas

196
Q

What happens in necrosis

A

Cells swell, lyse and ROS are released which causes damage to surrounding tissues resulting in inflammation and phagocytosis of necroses cell

197
Q

What happens in apoptosis

A

More controlled process in which the cell is turned off and packaged to be phagocytksed by neutrophils with no surrounding tissue damage

198
Q

Where are lymphocytes produced?

A

In the bone marrow but they mature in the thymus

199
Q

Which immune cells express class II MHC proteins

A

Macrophages, B cells and dendrite cells

200
Q

What are the 5 types of antibody

A

IgA, IgD, IgE, IgG (most abundant) and IgM

201
Q

What do antibodies recognise

A

Specific epitopes

202
Q

How does antigen presentation activate Cytotoxic T cells

A
  1. antigen presenting cell ingest bug
  2. Bug antigen is displayed on the antigen presenting cell surface with MHC II molecule
  3. both must be recognised
  4. Cytotoxic CD8 T cells become activated which bind to the infected cell
  5. They use perforin to make hles in infected cell membrane causing cell to lyse
203
Q

How does antigen presenting cells activate T helps cells

A
  1. Antigen presenting cell ingests bug
  2. Bug antigen is displayed of APC surface with MHC II - both must be recognised
  3. Interactions with T cell receptor releases cytokines
  4. CD4 cells differentiate into T-helper cells
204
Q

What is secreted by immature plasma cells

A

IgM

205
Q

What is a type 1 reaction

A

IgE - allergic, acute

Immunological memory to something causes an allergic reaction

206
Q

Give examples of type 1 immune reactions

A

Acute anaphylaxis and hay fever

207
Q

What is a type 2 reaction

A

IgG and IgM bind to cell surface antigens

208
Q

Give examples of type 2 reactions

A

Transfusion and autoimmune disease

209
Q

What is a type 3 reaction

A

Immune complexes, activation of complement IgG

210
Q

What are type 4 reactions

A

T cell mediated delayed type hypersensitivity

211
Q

give examples of a type 4 reaction

A

Tuberculosis

Contact dermatitis

212
Q

What is PaCo2 directly proportional to?

A

1/alveolar ventilation

213
Q

Write an equation to determine PAO2

A

PiO2 - PaCO2/R

214
Q

What is PiO2 and can it change

A

Pressure of inspired oxygen and yes it can change

215
Q

What is FiO2 and can it change?

A

Fraction of inspired oxygen and no it can’t change (Fixed at 0.21)

216
Q

What is PaO2 at sea level?

A

10.5-13.5 KPa

217
Q

What is PaCO2 at sea level?

A

4.5-6.0KPa

218
Q

As altitude rises, what happens to pressure?

A

It decreases in a non linear fashion

219
Q

What is the effect of altitude on the lungs?

A

Hypoxia leads to hyperventilation which increases the minute ventilation, lowers PaCO2 and leads to alkalosis and tachycardia which is compensated for by renal bicarbonate excretion

Phase 1 M (11 decks)

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