Respiratory Flashcards

1
Q

Regions of the pharynx?

A

Pharynx = throat
1. Nasopharynx (nostrils to soft palate)
2. Oropharynx (soft palate to hyoid bone)
3. Laryngopharynx (hyoid bone to cricoid cartilage/oesophagus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Impact of vocal cord movement on speech?

A

Cords adducted = high pitched sound
Cords abducted = lower pitch sounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Difference between conducting zone and gas exchange zone of the lungs?

A

Conducting zone - terminal bronchioles, high resistance to airflow
Gas exchange zone - respiratory bronchioles/alveoli, very low resistance to airflow, pleural pressure more negative at apex (with bigger gradient in taller people)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Levels of the bronchial tree

A

Trachea -> primary bronchi -> secondary (lobar) bronchi -> tertiary (segmental) bronchi -> bronchioles -> terminal bronchioles -> respiratory bronchioles -> alveolar ducts -> alveolar sacs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the bronchopulmonary segments?

A

Each portion of lung supplied by each tertiary bronchus is called the bronco pulmonary segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Overview of bronchioles

A

Continuations of airways that lack supportive cartilage
Each portion of lung ventilated by one bronchiole is a pulmonary lobule
Walls made of well-developed smooth muscle (ciliated cuboidal epithelium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Anatomy of terminal bronchioles

A

50-80 branch from bronchioles
No mucous glands or goblet cells, but retain cilia
Last area of the CONDUCTING zone (conducts air)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Anatomy of respiratory bronchioles

A

First part of the RESPIRATORY zone
Narrowed airways of the lungs
Alveoli bud from walls
Not much smooth muscle or cilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Anatomy oc alveolar ducts

A

2-10 from each respiratory bronchiole
Alveoli along walls
No cilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Overview of alveoli

A

150million in the lungs
70m2 surface area for gas exchange
Types of cells include type 1, type 2 and alveolar macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Type 1 alveoli

A

95% surface area
Squamous cells
Function for rapid gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Type 2 alveoli

A

5% surface area
Cuboidal and much more numerous than type 1 (although less surface area)
Function to repair alveolar epithelium and secrete surfactant
Surfactant = protein and phospholipid solution that coats alveoli and prevents collapse during exhalation due to reducing surface tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Alveolar macrophages

A

Most numerous cells in the lung
In alveoli and surrounding connective tissue
Function to remove foreign matter and bacteria via phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Respiratory membrane

A

= barrier between alveolar air and blood
Made up of squamous alveolar cells (type 1), basement membrane (shared) and squamous endothelial cell of capillary (pulmonary arterial supply)
Total thickness of 0.5micrometres
Pulmonary circulation MAP 10mmHg (allows gas exchange and keeps alveoli dry)
Oncotic pressure 25mmHg in alveolar capillaries, therefore keeps alveoli dry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Parietal pleura

A

Reflection of visceral pleura on the inner surface of the chest wall, mediastinum, diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Visceral pleura

A

Serous membrane covering the surface of lung to hilum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pleural space

A

Refers to space between parietal and visceral pleura
Contains pleural fluid, is a potential space
Functions to reduce friction, create pressure gradient for ventilation, compartmentalisation to reduce spread of infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What type of embryonal tissue does the respiratory system develop from?

A

Endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Embryonic stage of lung development

A

Week 4-5 (other resource says week 3)
Lung buds originate from the primitive foregut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Pseudoglandular stage of lung development

A

Approx week 5-16
Airway branching begins, lobar structure apparent
By the end of this phase, all the conducting airways have been fully developed, and the vascular development is complete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Canalicular stage of lung development

A

Approx week 16-25
Bronchioles are produced, increasing number of capillaries
Type 1 and II alveolar cells form
Air-blood barrier forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Saccular stage of lung development

A

Approx week 24-36 weeks
Alveolar ducts and air sacs are developed
Vascular expansion occurs
True alveoli seen by 32 weeks, recognisable by 36 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Alveolar stage of lung development

A

Occurs from late gestation (32 weeks onwards) to childhood
Marked increase in the number and size of capillaries and alveoli
Most development is postnatal (85% of alveolarization occurs postnatally)
15 million alveoli at birth (term baby) -> 300-600 million as an adult (exponential increase until 2 years old)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Overview of lung development postnatally

A

Birth to 3 years: formation of true alveoli, further complexity of gas-exchange airways
3-8 years: increase size and complexity of alveoli, pores of Kohn (collateral ventilation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Surfactant development and production

A

Type II alveolar cells present from 20-24 weeks
Surfactant secretion from 30 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Neurological regulation of respiration

A

Central control centre = 2 groups of neurons
1. Brainstem (pons and medulla) = pre Botzinger complex
2. Cortex (voluntary control)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Brainstem regulation of respiration

A

Neurons in medulla and pons control inspiration (dorsal respiratory centre) and expiration (ventral respiratory group)
Pneumotaxic centre controls rate and pattern of breathing, limits inspiration
Inputs from peripheral sensors, can be overridden by cortex
Automatic rhythmic inspiratory stimuli and sometimes expiratory
Major output is to the phrenic nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Cortex regulation of respiration

A

Cerebral motor cortex and limbic structure, voluntary control
Receives sensory input from respiratory muscles via corticobulbar and corticospinal tracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Respiration sensors

A
  1. Central chemoreceptors
  2. Peripheral chemoreceptors
  3. Lung and other receptors (pulmonary stretch, irritant receptors, J receptors, muscle receptors, arteriolar baroreceptors and pain/temperature receptors)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Overview of central chemoreceptors and regulation of respiration

A

Situated on ventral surface of medulla, surrounded by CSF
Respond to CSF [H+]
CSF [H+] is a reflection of CO2 in cerebral capillaries
Increased PaCO2 leads to increased CSF [H+], leads to increased ventilation
Does not respond to PaO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Overview of peripheral chemoreceptors and regulation of respiration

A

Situated in carotid bodies at bifurcation of common carotid arteries in neck, and aortic bodies around arch of aorta
Rapid response
Respond to decreased PaO2, decreased pH, increased PaCO2, leading to increased ventilation

32
Q

Overview of pulmonary stretch receptors

A

Located in airway smooth muscle of bronchi, bronchioles and visceral pleura
Function to respond to inflation of lungs (reduce RR in response to inhibition of inspiratory muscle activity)
Input to the dorsal respiratory group via the vagus nerve
Herring-Breuer reflex

33
Q

What is the Herring-Breuer reflex?

A

Excessive inflation of the lungs triggers this reflex, which is protective to further inflation as it inhibits inspiratory neurons

34
Q

Overview of irritant receptors

A

Found in epithelial cells of the airway
Stimulated by smoke, dust, pollen, chemicals, cold air, mucous
Inputs to the dorsal respiratory group via vagus nerve
Results in bronchiole smooth muscle effects = bronchoconstriction, shallow breathing, apnoea, cough

35
Q

What are J receptors?

A

At justacapillary location
Stimulated by interstitial and alveolar oedema
Trigger shallow breaths and tachypnoea

36
Q

Function of muscle receptors for regulation of respiration?

A

Sense stretch of diaphragmatic/intercostal muscles

37
Q

Impact of REM sleep on respiration

A

Marked suppression of postural muscle tone
Chest wall is more compliant which can affect air flow
Relaxation of upper airway muscles can cause obstruction
Predominant sleep pattern in preterm infants, full term newborn has for 50% of sleep

38
Q

How does a fetus/newborn/young infant respond to hypoxemia?

A

Will hyperventilate in response to hypoxemia (after a brief period of hyperventilation)
Improves as carotid chemoreceptors mature
Muscles are also more easily fatigueable

39
Q

What is elastance?

A

Property that opposes deformation of stretching

40
Q

Overview of compliance

A

Compliance = change in volume / change in pressure
Compliance is the distensibility of a substance
Reciprocal of elastance
Compliant lungs expand easily, a less compliant lung does not

41
Q

What is elastic recoil?

A

Property of a substance that enables it to return to original state, after it is no longer subjected to pressure

42
Q

What is resistance?

A

Amount of pressure required to generate flow of gas across the airways
Infants have smaller airways therefore prone to marked increase in resistance from inflammation/secretions

43
Q

What is the time constant?

A

Time constant = compliance x resistance
Refers to the amount of time required for alveoli to equilibrate with atmospheric pressure (airway pressure)

44
Q

Reduced compliance (pneumonia, pulmonary oedema, atelectasis) and impact on time constant/ventilation

A

Shorter time constant therefore less time for alveolar inflation and deflation
- would need to ventilate with shorter inspiratory times, smaller tidal volumes and faster rates

45
Q

Increased resistance (asthma, bronchiolitis, MAS) and impact on time constant/ventilation

A

Prolonged time constant, therefore more time for alveolar inflation and deflation
- would need to ventilate with slower rates and larger tidal volumes to enable gas exchange with equilibration of gas and avoid inadvertent PEEP due to inadequate expiratory time

46
Q

Boyle’s law

A

Pressure of given quantity of gas is inversely proportional to volume (assuming constant temperature)

47
Q

Henry’s law

A

At this air-water interface, the amount of gas that dissolves in water is determined by its solubility in water and its partial pressure in air (assuming constant temperature)

48
Q

Charles’s law

A

The volume of the given quantity of gas is directly proportional to absolute temperature (assuming constant pressure)

49
Q

Dalton’s law

A

Total pressure of a gas mixture is equal to the sum of the partial pressures of its individual gases

50
Q

Poiseuille’s equation

A

Describes relationship between diameter and resistance to flow
Resistance = L / R^4
? (8 x length) / R^4

51
Q

Laplace’s law

A

The larger the surface tension, the greater the pressure within alveoli
The smaller the radius, the greater the pressure within alveoli
P = surface tension / radius

52
Q

Most common colonising pathogen in children with CF?

A

Staph aureus (25% will be MRSA)
Haemophilus and P aeruginosa are also very common

53
Q

Overview of congenital diaphragmatic hernia

A

Can present within 24 hours of birth
Bowel in intrathroacic cavity causes pulmonary hypoplasia and displacement of mediastinum
Usually diagnosed antenatally, but should consider if mum has not had antenatal morphology scans

54
Q

How is compliance calculated using the single-breath occlusion method?

A

The total exhaled volume divided by pressure at the airway opening recorded during occlusion:
- infant’s airway briefly occluded at end inspiratory part of tidal breath
- induction of Hering-Breuer reflex leads to respiratory system relaxation during occlusion and immediately after occlusion released
Compliance = change in volume / change in pressure

55
Q

What is bronchiolitis obliterans?

A

Epithelial injury to the lower respiratory tract leading to obstruction and obliteration of distal airways
Injury can be due to infection or post-transplant
Commonly associated with adenovirus or mycoplasma

56
Q

Clinical features of bronchiolitis obliterans?

A

Tachypnoea, dyspnoea, persistent cough, wheeze unresponsive to bronchodilators

57
Q

Investigation findings in bronchiolitis obliterans?

A

LFT: airways obstruction with no significant bronchodilator response
CT: mosaic hyperinflation, bronchiectasis and vascular attenuation (pathognomonic)
Definitive diagnosis made with lung biopsy

58
Q

What is dynamic tacheomalacia?

A

The dynamic collapse of the trachea during breathing, most lesions are intrathoracic leading to airway collapse during expiration

59
Q

Overview of subglottic stenosis

A

Subglottis = narrowed portion of trachea, diameter 5-7mm at birth
Narrowing of 1mm = decrease in cross-sectional area by 75% and increase in airway resistance by 16x
Second most common cause of stridor (after laryngomalacia), with biphasic or usually inspiratory stridor
Usually present with URTI, recurrent croup common

60
Q

Extrathoracic causes of obstruction

A

Acute: croup, epiglottitis, retropharyngeal abscess, diphtheria
Chronic: laryngomalacia (most common), tracheomalacia, vocal cord paralysis, subglottic stenosis

61
Q

Intrathoracic causes of obstruction

A

Predominantly congenital - vascular rings, webs, external compression by tumours, lymph nodes

62
Q

Overview of laryngomalacia

A

Collapse of supraglottic structures during inspiration (c/w tracheomalacia which is an abnormally compliant trachea)
Clinical features = low pitched stridor, loudest 4-8 months then resolve by 12-18 months, more intense with URTI/crying/feeding

63
Q

The administration of which medication during an acute asthma exacerbation has been proven to reduce the duration of a hospital admission?

A

Oral prednisolone

64
Q

The thymus becomes less visible on CXR at what age?

A

Becomes gradually less evident between the ages of 2-8 years, after which it cannot be visualised on the frontal CXR

65
Q

What is minute volume?

A

Minute volume = tidal volume x respiratory rate
Higher minute volume will remove more CO2 and thus decrease arterial CO2 concentration, i.e. ventilation is primarily affected by minute volume

66
Q

Oxygenation is primarily affected by which factors?

A

FiO2
Mean airway pressure
Lung volume

67
Q

What type of noisy breathing will an extra thoracic narrowing of the trachea cause?

A

Inspiratory stridor

68
Q

Clinical features of hypersensitivity pneumonitis?

A

Chronic cough, known antigen exposure, FTT, pulmonary hypertension (loud P2)
Most common cause in children is exposure to birds

69
Q

Investigation findings in hypersensitivity pneumonitis?

A

CT findings of pneumonitis (centrilobular nodules, ground-glass opacities and air-trapping)
Polymorphonuclear leukocytosis with eosinophilia on bloods
Test for antigen specific serum precipitins = avian antigens are most common, also consider bacteria, fungi, mycobacteria, animal and plant proteins, chemicals and metals

70
Q

What type of virus is COVID?

A

Positive sense single stranded RNA virus

71
Q

Examples of negative sense single stranded RNA viruses?

A

Ebola, rabies

72
Q

Examples of positive sense single stranded RNA viruses?

A

Dengue, MERS, SARS, rhinovirus, COVID
- these can be directly translated into viral proteins by the host cell

73
Q

CF patient with cough, wheeze, reduced exercise tolerance, with elevated total serum IgE?

A

= allergic bronchopulmonary aspergillosis
A hypersensitivity reaction to a preceding fungal infection, clues are high IgE and wheeze
CT usually shows bronchiectasis with mucous plugging

74
Q

Significance of nasal polyps in children under 10 years?

A

Red flag for cystic fibrosis, or less commonly primary ciliary dyskinesia, immunodeficiency or vasculitis
- particular concern for CF if associated with poor weight gain, lethargy and abdominal pain

75
Q

Risk factors for benign nasal polyposis?

A

Recurrent infections, allergic rhinitis, tobacco smoke exposure, environmental pollution, reflux, foreign bodies

76
Q

Most common airway abnormality in Down syndrome?

A

OSA: 50-97%
Laryngomalacia: 50%
Tracheomalacia: 33%
Lingual tonsil: 30%
Complete tracheal ring: 17%