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Phase 1 Notes > Respiratory > Flashcards

Respiratory Flashcards

1
Q

What is the average rate of inspired gas?

A

5L/min (like cardiac output)

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2
Q

What are the muscles of respiration?

A

Diaphragm - mainly inspiration
External intercostals

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3
Q

What nerves is associated with the respiratory pump?

A

Sensory receptors assess flow, stretch etc
C fibres
Afferent via vagus nerve
Autonomic sympathetic, parasympathetic

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4
Q

What is a resting volume

A

Volume in lungs when there is no force exerted by chest wall and muscles

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5
Q

Ventilation vs perforation

A

Ventilation = Bulk airflow in alveoli
Perforation = Pulmonary blood supply in capillaries

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6
Q

How much dead space volume is present?

A

(Volume of air not contributing to ventilation)
1. Anatomical (doesn’t reach alveoli) ~ 150mls
2. Alveolar (alveoli not perfused) ~ 25mm

Physiological (Anatomic + Alveolar) = 175mls

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7
Q

What is the blood supply to the lungs?

A

Bronchial arteries
(+ Bronchial veins)

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8
Q

Describe alveolar perfusion

A

1000 capillaries per alveolus and each erythrocyte may come into contact with multiple alveoli = 25% through capillary and haemoglobin is fully saturated at rest

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9
Q

Perfusion of capillaries depend on:

A

Pulmonary artery pressure
Pulmonary venous pressure
Alveolar pressure

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10
Q

What is hypoxic pulmonary vasoconstriction?

A

In response to hypoxia in lungs, vasoconstriction moves blood to alveoli where gas exchange occur

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11
Q

How to calculate arterial CO2?

A

PaCO2 = constant (k) x CO2 production (VCO2)
—————————————————-
Alveolar ventilation (VA)

Normally = 4-6KPa

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12
Q

3 ways CO2 is carried

A
  1. Bound to haemoglobin
  2. Dissolved in plasma
  3. As carbonic acid
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13
Q

How to calculate alveolar O2?

A

PAO2 = PiO2 - PaCO2/Respiratory Quotient (R)

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14
Q

What are some causes of low PaO2 (hypoxaemia)?

A

Alveolar hypoventilation
Reduced PiO2
Ventilation/Perfusion mismatch (V/Q)
Diffusion abnormality

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15
Q

Describe the oxygen disassociation curve

A

As each O2 binds, a conformational shape change of haemoglobin makes the subsequent binding easier.

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16
Q

What is the oxygen disassociation curve influenced by?

A

Low pH, Increased CO2 shifts curve to right in highly respiring areas.
Temperature also affects

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17
Q

What blood gases can be easily measured?

A

PaCO2
PaO2
pH
HCO3-

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18
Q

What is the normal blood pH?

A

7.4pH (pH = -log 10[H+])

Maintained closely for optimal function

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19
Q

Describe blood buffers

A

CO2 (rapid) under respiratory control
HCO3- (less rapid) under renal control

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20
Q

What is the Henderson-Hasselbach equation

A

pH = 6.1 + log10[[HCO3-]/[0.03*PCO2]]

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21
Q

Respiratory vs Metabolic acidosis

A

Resp - Increased PaCO2, Decreased pH
Metabolic + Decreased HCO3-, decreased pH

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22
Q

Respiratory vs Metabollic alkalosis

A

Respiratory - Decreased PaCO2, increased pH
Metabollic - Increased HCO3-, increased pH

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23
Q

What does … stand for? TLC, VC, RV, IRV, FRC, ERV, IC, TV

A

Total Lung Capacity
Vital Capacity
Residual Volume
Inspiration Reserve Voljme
Functional Residual Capacity
Expiration Reserve Volume
Inspiration Capacity
Tidal Volume

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24
Q

FEV1 vs FVC

A

FEV1 = Forced expiratory Volume in 1 second
FVC = Forced vital capacity

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25
Q

Describe points on a forced expiration graph. (Flow/volume plot)

A

PEF = peak flow at top
FEF25 = flow at point when 25% of total exhaled
FVC = forced vital capacity = maximum volume

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26
Q

Peak flow meter/ spirometer gives readings in what measurement?

A

Litres/min

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27
Q

How can we measure RV and TLC?

A

Gas dilution - measures all air in lungs that communicate with airways
Body box (plethysmographs) - gas trapped in bullseye and panting changes box pressure proportional to volume of air in chest

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28
Q

Give equations = TLC

A

RV + VC
IRV + TV + FRC
(FRC = EV + RC)
IC + FRV

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29
Q

What is TLCO?

A

An overall measure of interaction between:
- alveolar SA, alveolar perfusion, capillary volume, haemoglobin concentration etc

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30
Q

How do we estimate TCO?

A

Carbon monoxide has high affinity for haemoglobin
= Single 10 s breath holding technique

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31
Q

What is a normal value for overall lung health?

A

FEV/FVC greater than or equal to 80%

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32
Q

FEV/FVC values for airway restriction and obstruction

A

Restriction <80%
Obstruction <70%

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33
Q

Input signals for respiration

A

Central + Peripheral chemoreceptors
Lung receptors hStretch, Irritant, J receptors)
Voluntary control (cerebrum)
Muscle proprioceptors
-> Respiratory control centre in medulla + pons
-> Spinal motor neurones
-> Muscles of respiration

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34
Q

Describe how the pons and medulla control breathing rates

A

Pons
- Pneumotaxic (inspiration)
- apneustic (inspiration + expiration)

Medulla = Phasic action potentials by 2 groups:
- Dorsal Respiratory group (DRG) active during inspiration (Lung + peripheral chemo to here)
- Ventral Respiratory group (VRG) active in both inspiration and expiration
Each are bilateral and interconnect in unconscious bulbo-spinal motor neurone pools

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35
Q

What is the central latter generator?

A

Located within DRG/VRG is a neural network of interneurones that start, stop and reset ventilatory drive

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36
Q

Describe excitation of respiratory muscles during inspiration and expiration

A

Inspiration - Excitation increases and rapid decrease at end
Expiration - Passive due to elastic recoil of thoracic wall but further muscle activity with increased demand

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37
Q

Describe chemoreceptors

A

Central in brain stem pontomedullary junction - sensitive to PaCO2 (diffuses into CSF), with some by [H+] and gas partial pressures
Peripheral in carotid and aortic arch - sensitive to hypoxia mainly (Type 1 cells release neurotransmitters that stimulate carotid sinus nerve), PaCO2, pH

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38
Q

Describe lung receptors

A

Stretch = smooth muscle of conducting airways sense lung volume, slowly adapting
Irritant = Larger conducting airways rapidly adapt
J (Juxtapulmonary capillary) = Pulmonary and bronchial C fibres

  • Assists with lung volumes and responses to noxious inhaled agents
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39
Q

What are muscle proprioceptors?

A

Joint, tendon and muscle spindle receptors between intercostal muscles and diaphragm for perception in breathing effort

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40
Q

Describe some airway receptors

A
  • Chemo and mechanoreceptors in nose, nasopharyngeal and larynx monitor flow
  • In the pharynx, receptors are activated by swallowing stop respiratory activity
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41
Q

What happens to blood gases during ascent?

A

Atmospheric PiO2 falls, but FiO2 is constant
= Decreased PAO2 and PaO2
= Peripheral chemoreceptors fire and ventilation increases
= In turn increases PAO2 and PaO2

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42
Q

Describe structure of nose

A

Anterior nares open into vestibule lined with skin and stiff hair.
Surface area is doubled by turbinates creating:
1. Superior meautus
- Olfactory epithelium, cribriform plate, sphenoid
2. Middle meats
- Sinus openings
3. Inferior meats
- Nasolacrimal ducts

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43
Q

Functions of the nose

A

Temperature of inspired air
Humidity
Filter
Defence (cilia take particulates to be swallowed)

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44
Q

Name the para nasal sinuses

A

Frontal - by opthalmic division of CN5
Maxillary - opens into middle meatus
Ethmoid - Between eyes into middle meatus (CN5-1,2)
Sphenoid - CN 5-1 empties into sphenoethmoidal recess (CN 3,4,5,6 travels through)

= Evagination of mucous membrane from nasal cavity helps resonate sound and heat air

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45
Q

Describe the pharynx structure

A

Fibromuscular tube lined with squamous and columnar ciliated epithelium and mucous glands.
- Nasopharynx contains Eustachian tube orifices to middle ear and pharyngeal tonsils
- Oropharynx contain palatine tonsils
- Laryngopharynx

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46
Q

Describe larynx structure

A

Rigid 9 cartilages and multiple muscle with valvular function
Arytenoid cartilage rotate on cricoid cartilage to change vocal cords

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47
Q

Name all single and double laryngeal cartilages

A

Single
- Epiglottis
- Thyroid
- Cricoid

Double
- Cuneiform
- Arytenoid
- Cornicultae

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48
Q

Describe laryngeal innervation

A

Superior laryngeal nerve
- Internal supplies sensation
- External supplies cricothyroid muscle
Recurrent laryngeal nerve
- Supplies all muscles but cricothyroid
- L loops under aorta, R under subclavian artery

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49
Q

Describe pathway of inspiration

A

Trachea
Main bronchi
Lobar bronchi
Segmental branches
Terminal bronchioles
Respiratory bronchioles
Alveolar ducts
Alveoli

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50
Q

Describe trachea structure

A

Larynx to carina
Lined by pseudostratified ciliated columnar epithelium with goblet cells
Semicircular cartilages

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51
Q

Where is food more likely to get stuck and why?

A

Right bronchi
= Wider and more vertical

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52
Q

How many lobes in each lung?

A

3 in right
2 in left

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53
Q

How to distinguish between terminal and respiratory bronchioles

A

Respiratory bronchioles have alveoli protruding from them

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54
Q

What interconnect alveoli?

A

Pores of Kohn equalise pressure

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55
Q

What 6 cells layers present in alveoli?

A

Type 1 pneumocytes
Type 2 pneumocytes - produce surfactant
Alveolar macrophages
Basement membrane
Interstitial tissue
Capillary endothelial cells
(plasma, Red cell membrane, cytoplasm, Hb)

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56
Q

Describe lung pleura innervation

A

Parietal has pain sensation
Visceral pleura only has autonomic

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57
Q

Describe branching of pulmonary circulation

A

17 orders of branching:
Elastic
Muscular
Arterioles <0.1mm
Capillaries

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58
Q

How does acute inflammation occur?

A

Vasodilation leads to exudate of plasma and antibodies
Activation of biochemical cascades e.g. complement and coagulation cascades
Migration of blood leukocytes into tissue
(mainly neutrophils but some monocytes)

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59
Q

How many adults get community acquired pneumonia

A

250 000 per year
Mortality ~ 10%

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60
Q

Name some inflammation-mediated tissue damage disorders in the lung

A
  • Chronic Obstructive Pulmonary Disease - Destruction of alveoli due to repeat inflammation
  • Acute Respiratory Distress Syndrome
    Activation of innate system inappropriately so fluid + neutrophils build up and multi system failure
  • Bronchiectasis
  • Interstitial Lung Disease
  • Asthma
61
Q

How is acute inflammation initiated and amplified?

A

Initiated by endothelial production of hydrogen peroxide and release of cellular content

Amplified by specialist macrophages including:
- Kupffer cells (liver)
- Alveolar macrophages (lung)
- Histiocytes (skin, bone)
- Dendritic cells

62
Q

Response to pathogen or tissue injury by recognising:

A

PAMPs (Pathogen Associated Molecular Patterns)
DAMPs (Damage Associates Molecular Patterns)

Using Pattern Recognition Receptors (PRR)

63
Q

Name some Pattern Recognition Receptors

A

Signalling
- Toll like receptors
- Nod like receptors
Endocytic
- Mannose receptors
- Glucan receptors
- Scavenger receptors

64
Q

Describe alveolar macrophages

A

Comprise 93% of pulmonary macrophages and arise from.monocytes.
Can change their phenotype to suit the environment e.g. switches to tissue repair for healing after

65
Q

Describe neutrophils

A

70% of all wbc, contains primary granules that kill bacteria and secondary granules (receptors, lysozyme, collagenase)
Half are free flow and half are near endothelium = allows fast response

66
Q

Describe neutrophil functions

A
  1. Identify threat - GPCRs, FC-receptors etc
  2. Activation - signal transduction pathways involving calcium, kinase, G proteins, phospholipase
  3. Adhesion - Selectins capture and Integrins adhere requires change in endothelium + neutrophil
  4. Migration/Chemotacis - moving receptors down concentration gradient
  5. Phagocytosis
  6. Bacterial killing - lysosomes and ROS generated
  7. Apoptosis - cell death
67
Q

Intrinsic vs Innate vs Adaptive

A

Intrinsic = Always present (Apoptosis, RNA silencing, antiviral proteins)
Innate = Induced by infection (Interferon, cytokines, macrophages, NK cells)
Adaptive = Tailored to a pathogen (T/B cell)

68
Q

How is the respiratory epithelium a physical defence?

A

Moistens and protects airways
A physical barrier to potential pathogens and foreign particles by mucocilary escalator

69
Q

Describe how epithelium changes down the airway

A

Nasal cavity + pharynx = respiratory
Inferior pharynx = stratified squamous against abrasion
Lower tract = respiratory
Bronchioles = cuboidal
Alveoli = simple squamous for gas exchange

70
Q

What are some chemical epithelial barriers?

A

Molecules secreted from epithelium:
Antiproteinase
Anti-fungal peptide
Anti-microbial peptide
Antiviral proteins
Opsins

71
Q

How are submucosal glands defensive?

A

A viscoelastic gel containing water, carbohydrates, proteins and lipids protects epithelium from foreign material and fluid loss. Transported from lower respiratory tract into pharynx by air flow and mucociliary clearance

72
Q

What is a cough?

A

Expulsive reflex either voluntarily or reflexively that protects lungs and respiratory passages from foreign bodies.
Causes include irritants, infections and diseases like COPD
Afferent includes receptors from CN 5, 9, laryngeal
Efferent includes recurrent laryngeal + spinal nerves

73
Q

What is a sneeze?

A

An involuntary expulsion of air containing irritants from nose
Causes included irritation and excess fluid

74
Q

Following an injury, how can the airway epithelium effect a complete repair

A

Spreading and Differentiation
Cell migration and proliferation
Redifferentiation and regeneration
Plasticity exists in multiple cells

75
Q

What is average PAO2?

A

PAO2 = PiO2 - PaCO2/R
= 20 - 6/0.8
= 12.5 KPa

76
Q

Define respiratory failure

A

Failure of gas exchange so inability to maintain normal blood gases.
Low PaO2 with or without a rise in PaCO2

77
Q

Type 1 respiratory failure

A

Hypoxia < 8 KPa
Normal PaCO2 4-6 KPa

78
Q

Type 11 respiratory failure

A

Hypoxia < 8 KPa
Hypercapnia > 6.5 KPa

79
Q

Hypoxaemia vs Hypoxia

A

Hypoxaemia - environment has low O2
Hypoxia - Tissue has low O2

80
Q

Acute vs Chronic respiratory failure examples

A

Acute = opiate overdose, trauma, pulmonary embolism

Chronic = COPD, fibrosing lung disease

81
Q

Type 1 respiratory failure mechanisms and treatment

A

Ventilation/Perfusion mismatch
Shunting
Diffusion Impairment
Alveolar hyperventilation

Treat = O2 delivery

82
Q

Type 11 respiratory failure mechanisms and treatment

A

Lack of respiratory drive
Excess workload
Bellows failure

Treatment = O2 delivery with certain cautions

83
Q

Hypoxia clinical features

A

Irratibility
Reduced intellectual function or consciousness
Central cyanosis

Convulsions
Coma
Death

84
Q

Hypercapnia clinical features

A

Irritability
Headache
Warm skin
Bounding pulse
Confusion
Coma

85
Q

Why should we be careful giving oxygen to type 11 respiratory failure?

A

High HCO3- and chronic acidosis resets central chemoreceptors so not sensitive to rise in CO2. Therefore they rely on hypoxia to breathe = Don’t give O2

86
Q

During oxygen treatment, what SpO2 should we aim for?

A

94-98%

87
Q

AP vs PA x-ray

A

Anterior-Posterior = When sick patients can’t stand, Patient faces x-ray generator
-> Larger but blurr and inaccurate images
Posterior-Anterior = Patient faces x-ray detector (ideal)
-> Crisper and accurate size images

88
Q

Define CT

A

Computerised Tomography is many individual x-rays put together and analysed in 3D
(= 2 years background radiation)

89
Q

Pulmonary vs Systemic arteries

A

Pulmonary - Thin wall and minor muscularization
Systemic - Thick wall, significant muscle and a need for redistribution

90
Q

Pressures in Right vs Left side of heart (mmHg)

A

RA = 5, LA = 5
RV = 25/0, LV = 120/0
PA = 25/8, Aorta = 120/80

91
Q

Give Pouiseuille’s law

A

Resistance = (8 x L x viscosity)
———————-
pi x r^4

Therefore small change in radius = great change in resistance

92
Q

What is Ohms law?

A

V = IR

93
Q

How to calculate pressure across pulmonary circulation?

A

Cardiac Output x Resistance
Or
mPAP - Left Atrial pressure x pulmonary vascular resistance
So
mPAP - PAWP = CO x PVR

94
Q

Increased pulmonary artery pressure leads to:

A

Recruitment of blood vessels and distention

95
Q

Give examples of 3 pulmonary circulation diseases

A

V/Q mismatch: Pulmonary Embolism
Shunt: Pulmonary Arteriovenous Malformation
Increased PVR = Pulmonary Arterial Hypertension

96
Q

Describe hypoxic pulmonary vasoconstriction

A

A constriction (peanut) of the alveoli means blood is not ventilated and so HPV tries to redistribute blood by constricting blood vessels
= Aims to improve local and general hypoxia (e.g. altitude)

97
Q

What is pulmonary embolism?

A

Clots in lung causes peripheral infarction or central ischaemia (affects perfusion)

98
Q

What is Virchow’s Triad?

A

3 factors of developing thrombosis:
Endothelial injury
Stasis
Hypercoagulable state

99
Q

Define asthma

A

Common chronic inflammatory disease characterised by reversible obstruction and bronchospasm.
Environmental and occupational influences may include pets, fungi, pollen, hobbies, air pollution

100
Q

Define hypersensitivity pneumonitis

A

Inflammation of the alveoli caused by hypersensitivity to inhale dust
Caused by microbiological and chemical agents such as farms, musical instruments and bacteria in hot tubs

101
Q

Define COPD

A

Obstructive lung disorder worsens over time with FEV1/FVC <0.7.
Commonest cause is tobacco, but also occupational and environmental, affects e.g. coal, grain, cotton, silica, cadmium

102
Q

Does asthma run in families?

A

Yes - but not caused by single gene mutation or simple Mendelian inheritance.
Associated chromosomes = 2,6,9,15,17,22

103
Q

What genetic disorder is cystic fibrosis?

A

Autosomal recessive leads to multi-organ involvement and increasing Prevelance
= Defect in q arm of chromosome 7 coding for CFTR protein
= Abnormal CFTR protein doesn’t move Cl- so mucus builds outside of cells in Lungs and GI
(Frequent infections, malabsorption, infertility)

104
Q

What is pathophysiology - Vicious cycle?

A

Respiratory tract infection -> Bronchial inflammation -> Respiratory tract damage ->

105
Q

6 CF genotype classification

A
  1. No functional protein made
  2. CFTR protein misfolded
  3. CFTR protein doesn’t open properly
  4. Cl- doesn’t cross CFTR channels properly
  5. CFTR protein not made enough
  6. CFTR protein has decreased cell surface stability
106
Q

Which is the most common CF class?

A

2

107
Q

CF treatment

A

Phage therapy - Lytic bacteriophages to kill infectious bacteria
Ivacaftor
Maintenance
- Segregation of bacteria strains
- Airway clearance with physio
- Nutrition with high calorie + fat diet
Prevention
- Antibiotics, anti-inflammatory
- Brochodilation = salbutamol nebulisation

108
Q

Challenges treating CF

A

Adherence to treatment
High treatment burden
High cosy
Intolerance to treatment
Different infectious organisms and resistance to drugs

109
Q

Describe genotype of Alpha-1 anti trypsin deficiency (AATD)

A

Autosomal recessive mutation of SERPINEA 1 gene on chromosome 14
= Early onset emohysema and bronchiectasis

110
Q

1 Atomsphere Absolute is equivalent to m of sea water?

A

10 meters of sea water

111
Q

What is Boyle’s law?

A

At constant temperature, pressure of a fixed gas is inversely proportional to its volume
P1V1 = P2V2

112
Q

What is apnoea (diving reflex)

A

Pre-hyperventilation, then diver descends holding breath. Gas compresses as PaO2, PaN2, PaCO2 rise and N2 forced into alveoli.

113
Q

Define SCUBA

A

Self Contained Underwater Breathing Apparatus
= gas delivered on inhalation at ambient pressure

114
Q

What is Dalton’s Law?

A

Total pressure by a mixture of gases is equal to the sum exerted by each gas.

115
Q

Partial pressure at sea level vs 10msw

A

N2 = 0.78 vs 1.56 ata
O2 = 0.209 vs 0.418 ata

116
Q

What’s pulmonary oxygen toxicity?

A

When PiO2 >0.5 ata
= Cough, chest tightness and pain, shortness of breath

117
Q

What is Inert Gas Narcosis?

A

Commonest is nitrogen, worsens with increasing pressure
Influencing factors = cold, anxiety, fatigue, drugs, alcohol

118
Q

What is Arterial gas embolism?

A

Gas enters circulation via torn pulmonary veins
= Needs urgent decompression

119
Q

What is the pressure of inspired oxygen at sea level?

A

21KPa

120
Q

What is the death zone?

A

Over 8000m without additional O2

121
Q

What is PAO2 and PaO2 at sea level?

A

PAO2 = 12.5KPa
PaO2 = 12.5 - 1 = 11.5 KPa

122
Q

Normal response at altitude

A

Hypoxia leads to hyperventilation

123
Q

Describe 3 high altitude illnesses

A

A true mountain sickness - recent ascent over 2.5km results in headache, eases by descent

High altitude Pulmonary Oedema - rapid ascent over 2400m for 2-5 days results in cough + shortness of breath. Treat with decent, O2 etc

High Altitude Cerebral Oedema - serious confusion and behaviour change.- needs immediate descent

124
Q

When to avoid flying?

A

(Cabin = 81KPA compared to sea level = 21KPa)
Pneumothorax
Infectious TB
Major Haemoptysis

125
Q

Stages of lung development in weeks

A

Embryonic 0-5 weeks
Pseudoglandular 5-17 weeks
Cannalicular. 16-25 weeks
Alveolar. 25 weeks-term

126
Q

Describe the embryonic stage of lung development

A

Anterior outpouching of foregut oesophageal appendix forms the respiratory diverticulum. By 5th week, the lungs bud enlarge to form right and left main bronchi

127
Q

Describe the pseudoglandular phase

A

Exocrine, mucous glands and major structural units form. Angiogenesis allows cartilage, smooth muscle, cilia and lung fluid to form major airways

128
Q

Describe the canalicular phase

A

Vascularisation of capillary bed and respiratory bronchioles form. Terminal sacs and alveoli ducts also form

129
Q

Describe alveolarisation phase

A

Type 1 and 2 cells form alveolar sacks
(3-5yrs = thinning of alveoli increase complexity)

130
Q

Systemic vs pulmonary blood vessels

A

Systemic = deliver oxygen to tissue
So hypoxia/acidosis/CO2 are vasodilators
Oxygen is vasoconstrictor

Pulmonary = pick up oxygen
So oxygen is vasodilators
Hypoxia/acidosis is vasoconstrictor

131
Q

Describe foetal blood circulation

A

Umbilical vein from placenta
Ductus venosus shunts to IVC through liver
Foremen ovale shunts RA to LA
Ductus arteriosus shunts pulmonary trunk to aorta
To umbilical artery

132
Q

Describe the first breath

A

(Fluid actively secreted in and aids lung development)
Fluid squeezed out of lungs and airways
Adrenaline stress increases surfactant produce
Air = oxygen vasodilators pulmonary artery
Ductus arteriosus and umbilical artery constricts
Tissue resistance reduces
R sided heart pressure reduces

133
Q

What’s Laplace’s law?

A

Smaller alveoli are preferentially shut due to surface tension

134
Q

Describe surfactant in lungs

A

Contains phospholipids: choline, glycerol, inositol and surfactant proteins A, B, C, D

Produced by type 2 pneumocytes from 34 weeks and dramatic increase 2 weeks prior to birth
Accelerated by alveoli distension, steroids and adrenaline

135
Q

Functions of surfactant

A

Abolition of surface tension
Allows homogenous aeration
Allows maintenance of functional residual capacity

136
Q

Describe the different antibodies

A

Produced by B lymphocytes to neutralise or eliminate pathogens.
IgM - Made at beginning of infection
IgG - Highly specific
IgE - In response to parasites, asthma…
IgA - Expressed in mucosa, and breast tissue
IgD - induces antibodies, activates basophils + mast cells

137
Q

Type 1 hypersensitivity

A

Immediately IgE antibodies attached to mast cells or basophils are released
Degranulation of mediators lead to local effects
Histamine is the predominant mediator
So manages with antihistamine + adrenaline
E.g. Anaphylaxis, Hayfever

138
Q

Type 2 hypersensitivity

A

Within hours to days, cytotoxic antibodies IgG or IgM bound to cell antigen
Due to: transfusions, goodpastures

139
Q

Type 3 hypersensitivity

A

After 7-12 days, antigen-immunoglobulin complexes are formed and deposit in tissues. This causes local activation of complement and neutrophils
Due to: hypersensitive pneumonitis

140
Q

Type 4 hypersensitivity

A

After Days to weeks or months , T-cells are released
Secondary reaction takes 2-3 days to develop
Due to: tuberculosis

141
Q

Asthma vs COPD

A

Asthma - Usually <50yrs stable with intermittent and variable symptoms. Responds well and likely to normalise with treatment

COPD - Usually >35yrs with more than 10 pack years. Common sputum with allergies and persistant symptoms. Less responsive to therapy and but never normal spirometry and progressive

142
Q

How are airways regulated?

A
  1. Autonomic nervous system
    - Parasympathetic acts on M3 muscarinic receptors to bronchoconstrict
    - Sympathetic act on Beta-2 receptors to bronchodilate
  2. Inflammation
143
Q

The autonomic nervous system conveys all outputs from the CNS to the body except for…

A

Skeletal muscle control

144
Q

Somatic vs Autonomic nerve structure

A

Somatic = Ach synapses once
Parasympathetic = Ach synapses twice with long preganglionic
Sympathetic- Ach and NAd synapses twice with short preganglionic

145
Q

How to treat asthma and COPD?

A

Anti-muscarinic or anti-cholinergic block M3 receptors so stop bronchoconstriction
E.g. LAMAs s daily reduce attacks

Beta-2 receptor activators cause bronchodilator
E.g. short acting (salbutamol) and long acting (salmeterol)

146
Q

Adverse effects of B2-agonists

A

Tachycardia
Hyperglycaemia

147
Q

What is the CO single breath transfer factor?

A

A good measure of gas exchange in the alveolar capillary

148
Q

What are features of pulmonary oxygen toxicity? ConVENTID

A

Convulsions
Visual disturbance
Ears
Nausea
Twitching
Irritability
Dizziness

Phase 1 Notes (9 decks)

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