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PBL SEM 2 > PBL 1 > Flashcards

PBL 1 Flashcards

1
Q

name 2 roles of the gas exchange system

A
  1. conducts oxygen into the body

2. removes co2 from the body

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2
Q

what is the purpose of the pleura and pleural fluid?

A

the 2 pleura allow optimal expansion and contraction of the lungs. the pleural fluid acts as a lubricant, allowing the layers to slide smoothly over each other friction free

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3
Q

what is the order of air passages from the trachea?

A

trachea —> primary bronchus —> secondary lobar bronchi —> tertiary segmental bronchi —> conducting bronchioles —> terminal bronchioles —> respiratory bronchioles

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4
Q

how many lobes do the lungs have and what are they divided by?

A

right has 3 — superior, middle, inferior
left has 2 — superior, inferior

separated by fissures — oblique and horizontal (only on right)

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5
Q

which lung is smaller and why?

A

left lung is smaller as it shares its side of the thorax with the heart

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6
Q

what borders do the lungs have?

A

anterior, inferior and posterior borders

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7
Q

what surfaces do the lungs have?

A

costal, mediastinal, diaphragmatic

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8
Q

what kind of epithelium is present in the trachea?

A

ciliated epithelium — protective barrier with cilia to waft things out of the respiratory tract

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9
Q

what are basal cells?

A

lung stem cells which replaced damaged cells

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10
Q

what are goblet cells?

A

secrete mucus

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11
Q

what are serous cells?

A

secretory cells

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12
Q

type 1 vs type 2 alveolar cells

A

type 1 — very thin simple squamous cells, non-ciliated, main site of gas exchange — covers 90% of alveolus
type 2 — produce surfactant to keep airways open (reduce surface tension), preventing airway collapse. also renew type 1 cells

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13
Q

what happens to the cells and cilia as you move down the airways?

A

cells start to become thinner and cilia start to disappear

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14
Q

name the lining cells

A

ciliated, intermediate, brush (stunted cilia — under research), basal epithelium

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15
Q

what makes up the contractile component in airways?

A

smooth muscle — controls calibre

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16
Q

what makes up the connective tissue in airways?

A

fibroblasts (produce matrix proteins that provide support/strucutre), intersitital cells (produce elastin), collagen, proteoglycans, cartilage

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17
Q

what immune cells are present in the airways?

A

mast, dendritic, lymphocytes, neutrophils, eosinophils, macrophage

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18
Q

what are submucosal glands?

A

sit under epithelial layer, surrounded by smooth muscle (causes mucus production when it contracts)

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19
Q

role of mucus

A

traps inhaled toxins, transports them out of the lungs by ciliary beating and cough reflex

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20
Q

role of smooth muscle in airways

A
  • surrounds all airways
  • responsible for calibre
  • controls level of surfactant protein and mucus production if it contracts around the gland
  • very thinly spread out in lower airways — blood vessels fused to the epithelial cells in alveoli (decreased diffusion distance)
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21
Q

describe the effects of disease on airways

A
  • airway narrows
  • mucus accumulation
  • muscular layer thickening
  • inflammatory cell infiltration
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22
Q

what is the forced vital capacity?

A
  • exhale as forcefully as you can

- total volume of air exhaled

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23
Q

how does forced expiratory volume differ to forced vital capacity?

A

it is the same but in a specified amount of time

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24
Q

what is the effect of bronchodilators on airways and when are they used in asthma treatment?

A
  • they are RELIEVERS = usually blue or green
  • cause smooth muscle to relax
  • short acting (1-2 hours) and long acting (up to 12 hours)
  • usually used when asthma symptoms appear
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25
Q

what is the effect of corticosteroids on the airways and when are they taken in asthma treatment?

A
  • they are PREVENTERS = usually brown, orange or red
  • inhaled corticosteroids reduce inflammation in the airways
  • used daily even when there are no symtoms
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26
Q

name 3 ways lung volume (+hence calibre) can be reduced

A
  • physical impedance (obesity)
  • cellular infiltration
  • vascular leak
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27
Q

what is a pneumothorax?

A

= a collection of air between the visceral and parietal pleura causing a real (rather than potential) pleural space
= a collapsed lung

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28
Q

what causes the lung to collapse?

A
  • gas flows into the pleural space, increasing the pressure to atmospheric pressure
  • lung partially collapses due to the elastic recoil pressure
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29
Q

classification of a pneumothorax

A

1) primary = no underlying lung disease
2) secondary = no underlying lung disease

a. spontaneous = the majority of spontaneous pneumothorax are minor and self resolve
b. traumatic = in a small number of cases, a one way valve forms, causing more air to enter the pleural space

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30
Q

what is a haemothorax?

A

a collection of blood in the pleural cavity — often associated with a traumatic pneumothorax

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31
Q

what happens in a tension pneumothorax?

A

= medical emergency

  • displaces mediastinal structures
  • compromises cardiopulmonary function
  • flow of air is one way (from lung into the pleural cavity) upon inspirtation — upon inspiration the air from the atm enters the pleural cavity (from stab wound) down the pressure gradient
  • upon expiration, the air can’t escape from pleural cavity as the pleural pressure doesn’t increase above the atm pressure
  • every inspiration results in a build up of air and pressure
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32
Q

what are the clinical features of a pneumothorax?

A
  • spontaneous = chest pain and breathlessness
  • pain = sudden onset, localised to the affected side and made worse on inspiration
  • dyspnoea
  • reduction in breath sounds on the affected side
  • movement of chest wall may be reduced
  • percussion note will be resonant
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33
Q

how do you diagnose a pneumothorax?

A
  • decreased or absent breath sounds over affected lung
  • confirmed by x-ray — will illustrate the collapse of the lung as extra black space, indicating the presence of air around the lung
  • in tension pneumothorax, the lung shrivels up away from the affecte side and the mediastinum (inc. trachea) will shift towards the unaffected side = trachea displacement

= ABSENT BREATH SOUNDS AND RESONANT PERCUSSION

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34
Q

what are the 4 steps to examine the chest?

A
  1. inspection
  2. palpation
  3. percussion
  4. auscultation
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35
Q

what does a chest drain underwater seal create and why is this important?

A
  • creates a one way valve
  • stops more air entering
  • usually in the form of an underwater seal
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36
Q

why are there sucking sounds at a wound?

A

noise of air entering and leaving the wound — not in a tension pneumothorax — here air enters the chest outside the lung but does not escape

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37
Q

why would engorged neck veins be visible?

A

there is an increase in intrathoracic pressure therefore it is harder for blood to return to the heart — therefore jugular vein distension

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38
Q

why would a patient have difficulty breathing with a pneumothorax?

A

build up of air puts pressure on the lung, so it cannot expand as much

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39
Q

why would you have a 3 sided dressing for a chest wound?

A

prevents additional air from entering the pleural cavity , whilst allowing trapped air to escape from the untaped edge during exhalation

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40
Q

why would there be a crackling swelling?

A

subcutaneous emphysema — air goes into fat

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41
Q

what is the principle of the ATLS protocol?

A

treat the greatest threat to life first

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42
Q

what is nociception?

A

the detection of painful stimuli

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43
Q

what do local anaesthetics inhibit?

A

inhibit action potential generation within cells

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44
Q

what is the mechanism of local anaethetics?

A

— bind reversibly to Na+ channels in the neuron cell membrane

  • pass across lipid membrane in an non-ionised state and become ionised inside the axon (intracellular environment more acidic)
  • ionised form is able to bind to the Na+ channel intracellular surface preventing Na+ ion entry and action potential generation

— nerve fibres are blocked in predictable sequence

  • preferentially block small diameter, myelinated and high frequency nerve fibres
  • sequence of fibres blocked
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45
Q

what is lidocaine?

A

an anaesthetic with minor analgesic properties

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46
Q

where is lidocaine injected?

A

into the 2nd intercostal space in mid-clavicular line

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47
Q

what is lidocaine used for?

A
  • given by IV infusion to treat and prevent ventricular dysrhythmias in the immediate aftermath of a myocardial infarction
  • also used as a local anaesthetic (analgesic) for minor surgery
  • widely used for local anaesthesia (analgesic) for needle aspirations/chest drains
  • has a 2 hour half-life — increased by reducing hepatic blood flow (97% clearance in 10 hours)
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48
Q

what is PTSD?

A

a condition where exposure to an intense and frightening emotional experience leads to lasting changes in behaviour, mood and cognition

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49
Q

what are the major symptoms of PTSD?

A
  • feeling numb to the world with a lack of interest in former activities with a sense of estrangement from others
  • reliving the trauma repeatedly
  • sleep disturbances
  • difficulty concentrating
  • over alertness
50
Q

what is CBT and what does it aim to do?

A

= cognitive behavioural therapy

  • CBT for PTSD is a structured therapy that is designed to desensitise the person to the traumatic event
  • reprocess the feared event and improve their strategies to decrease the sense of threat
51
Q

what muscles work in inspiration (not forced)?

A

= diaphragm and external intercostals

52
Q

what is the process of inspiration?

A
  • diaphragm contracts and moves downwards
  • external IC contract, elevate ribs outwards and upwards = enlarge thoracic cavity = increases lung volume = decreases pressure = pressure in lungs is lower than atm pressure so air rushes in
53
Q

what innervates the diaphragm?

A

phrenic nerve

54
Q

what innervates the external intercostal muscles?

A

intercostal nerves

55
Q

what is the process of expiration?

A
  • passive process
  • elastic forces of lungs compress alveolar air volume = increased pressure in lungs = Palv > Patm
  • diaphragm and external intercostal muscles relax = decreases thoracic cavity volume = increases pressure in lungs = air forced out
  • elastic recoil of lungs is sufficient — all respiratory muscles are relaxed
56
Q

what are the accessory muscles of respiration and what do they do?

A
  1. sternocleidomastoid = assists with the elevation of the sternum
  2. pectoralis major/minor = assist with the expansion of the ribs laterally
  3. serratus anterior = assist with the elevation of the rib cage
  4. latissimus dorsi = assists with the elevation of the lower rib cage
  5. scalenes = assist with the elevation of the upper rib cage
57
Q

what happens in forced expiration?

A
  • at the start, elastic recoil is the major force and external IC muscles breaking expiration
  • towards the end abdominal muslces are used to push air out
58
Q

if there is a lung puncture, what happens to the forces?

A
  • puncture has connected pleural space to the atm
  • Ppl = Palv = Patm
  • collapsed lung
59
Q

if you suck air out of pleural space to fix a collapsed lung, what are the pressure changes?

A
  • Ppl < Palv —> Ppl &laquo_space;Palv

- lung expands

60
Q

what is responsible for elastic recoil of the lung?

A
  • connective tissue fibres (collagen and most importantly elastin)
  • surface tension forces at the air/liquid interface of the alveolus
61
Q

what is the functional residual capacity?

A

the lung volume when the respiratory muscles are relaxed (after a normal passive exhalation)

62
Q

how does elastic recoil cause air to be forced out (in terms of pressure)?

A
  • elastic recoil begins to squeeze the alveolus space
  • Palv is +ve with respect to Patm
  • air is forced out
63
Q

what happens to Ppl during inspiration and expiration?

A
  • Ppl is decreasing as the pleural space is stretched during inspiration
  • increases to normal volume during expiration
64
Q

chest stab — why does lung collapse?

A
  • stabbing punctured the chest wall and possibly lung
  • now pleural pressure = atmospheric pressure
  • no force to counter elastic recoil
  • lung collapses
65
Q

how can a collapsed lung result in a tension pneumothorax?

A
  • lung collapses
  • the puncture acts as a one-way valve
  • air drawn into the pleural space with chest expansion
  • Ppl increases above central venous pressure
  • cardiac filling reduced
  • cardiac output and BP fall
66
Q

what is airflow = to?

A

airflow = driving pressure / airways resistance

driving pressure = Palv - Patm

67
Q

what is airways resistance proportional to?

A

length / radius^4

68
Q

why is there an increased work of breathing when there is an increased frequency of breathing?

A
  • having to move air faster

- have to generate a greater pressure gradient to move air faster in the same amount of time

69
Q

why is there an increased work of breathing for an increased tidal volume of breathing?

A
  • lung stretched more

- more force required to stretch the lung

70
Q

what parts of the respiratory tree are involved in gas exchange?

A

respiratory bronchioles and alveolar ducts and alveoli

71
Q

how volume of air does a typical adult breathe in?

A

0.5L

72
Q

what volume of air reaches the alveolar space and is involved in gas exchange in a typical adult?

A

350ml

73
Q

equation for ‘fresh air’

A

fresh air = tidal volume - dead space

74
Q

alveolar ventilation equation

A

alveolar ventilation = fresh air (= tidal volume - dead space) x breathing frequency

75
Q

is alveolar ventilation higher for fast or slow breathing?

A

for the same amount of pulmonary ventilation, slow deep breathing gives more alveolar ventilation that fast rapid breathing

76
Q

what is residual volume?

A

the amount of air that remains in the lungs after a forced exhalation (larger than dead space)
(many lung diseases increase ‘physiological’ dead space’)

77
Q

what is the role of chemoreceptors?

A

detect changes in the levels of oxygen and carbon dioxide in the arterial aortic bodies and the carotid bodies

78
Q

what are central chemoreceptors primarily sensitive to and where are they located?

A

primarily sensitive to the changes in CO2 and they are located in the medulla oblongata near to the medulla respiratory groups of the respiratory centre

79
Q

what respiratory groups are there? what does each do?

A

there are 4 — 2 in the medulla and 2 in the pons (pontine respiratory group)

  1. dorsal respiratory group (in medulla) = controls mostly movements of inhalation and their timing
  2. ventral respiratory group (in medulla) = controls voluntary forced exhalation and acts to increase the force of inhalation
  3. pneumontaxic centre (various nuclei of the pons) = coordinates speed of inhalation and exhalation. sends inhibitory impulses to the inspiratory area. involved in fine tuning of respiration rate
  4. apneustic centre (nucleus of the pons) = coordinates speed of inhalation and exhalation. sends stimulatory impulses to the inspiratory area — activates and prolongs inhalations. overridden by pneumotaxic control from the apneustic area to end inhalation)
80
Q

what respiratory groups control what (simplified)?

A
  • ventral: expiration
  • dorsal: inspiration
  • pontine: rate and pattern of breathing

once the neurons stop firing, the inspiration muscles relax and expiration occurs

81
Q

what are 5 causes of hypoxia?

A
  1. inadequate oxygenation of the blood in the lungs due to extrinsic reasons (eg. lack of O2 in the air)
  2. pulmonary disease
  3. venous-to-arterial shunts (‘right-to-left cardiac shunts’)
  4. inadequate oxygen transport to the tissues by the blood
  5. inadequate tissue capability of using oxygen
82
Q

what are the physical responses of stress?

A
  • increased SNS activity
  • arousal
  • CNS activation
  • fight/flight respone
83
Q

what is the fight or flight response (acute stress response)?

A
  • refers to the physiological reaction when there is a perceived threat
  • sympathetic nervous system is activated = increased HR/BP/breathing
  • an adaptive response to enable management of stress
84
Q

what are the 3 stages in the general adaptation syndrome response to stress?

A
  1. ALARM — recognising a stressor = body initiates fight or flight
  2. RESISTANCE — cope with or adapt to the stressor = maintain high metabolic rate, body cannot maintain this
  3. EXHAUSTION — depletion of resources if stressor cannot be overcome = symptoms reappear, can lead to a variety of health issues
85
Q

what did Lazarus argue?

A

argued that stress involved a transaction between the individual and their external world, and that a stress response was elicited if the individual appraised a potentially stressful event as actually being stressful (Transactional Model)

86
Q

according to Lazarus, what is primary appraisal?

A

the individual appraises the event itself via 4 possible ways:

1) irrelevant
2) benign (gentle) and positive
3) harmful and a threat
4) harmful and a challenge

87
Q

according to Lazarus, what is secondary appraisal?

A

the individual evaluates the pros and cons of their different coping strategies

88
Q

simplified primary vs secondary appraisal

A 
primary = appraisal of the outside world 
secondary = appraisal of the individual themselves
89
Q

what factors affect the stress-illness link?

A
  • exercise (decreases stress)
  • coping styles
  • social support (high SS = decreased stress response = reduction in illness)
  • personality
  • arousal or perceived control
90
Q

benefits of social support?

A
  1. improved adherance
  2. improved health outcomes
  3. effects are strongest in older patients
  4. better metabolic control — diabetes
  5. improved outcomes in kidney and heart patients
  6. triggers to consult
91
Q

what is the autonomic nervous system divided into?

A
  • sympathetic = fight or flight

- parasympathetic = rest and digest

92
Q

efferent vs afferent fibres

A
  • afferent (incoming nerves) : organs/tissues (info) —> CNS monitoring via sensort receptors/nerves
  • efferent (outgoing nerves) : CNS (instructions) —> organs/tissues
93
Q

what is a ganglion?

A

a conjunction of nerve cell junctions

94
Q

what does the vagus nerve supply?

A

(cranial nerve 10)

supplies thoracic and abdominal organs

95
Q

describe the PSNS

A
  • most active under quiet conditions (rest and digest)
  • 1st neurone usually in the brain (specifically brainstem = pons + medulla)
  • limited anatomical distribution (eg. no supply to limbs, skin, blood vessles, muscles)
96
Q

describe the SNS

A
  • fight or flight
  • 1st neurone (preganglionic) in particular spinal cord segment = T and upper 2-3 L segments
  • 2nd neurone (postganglionic) usually in sympathetic ganglion = chain either side of the spinal column
  • however some synapses in outlying ganglia ie. not in chain
97
Q

what do sympathic pathways use?

A

acetylcholine then noradrenaline. nicotinic receptor then adrenergic receptor (several types!!)

98
Q

what do parasympathic pathways use?

A

acetylcholine. nicotinic receptor then muscarinic receptor

99
Q

how do you switch off signals in the nervous system?

A

inactivating/removing released transmitters

either/or:

  • enzyme destorys transmitter
  • transmitter ‘re-coupled’ by presynoptic nerve terminals for re-use or destruction
100
Q

what enzyme breaks down Ach?

A

acetylcholinesterase

101
Q

what is CBT?

A

= cognitive behavioural therapy

- uses techniques to challenge problem thinking

102
Q

what is the primary goal of CBT for PTSD?

A

to undergo some sustained emotional processing of the traumatic memories

103
Q

how must CBT for PTSD be carried out?

A

in a controlled way

ie. graded exposure, systematic desensitisation

104
Q

what is self-efficacy?

A

a sense of power to affect one’s own behaviour

105
Q

what are 4 problem-focused coping strategies (taking action)?

A
  1. gathering information about the illness
  2. consulting appropriately
  3. seeking support
  4. self-management/engagement
106
Q

what are 6 emotion focused coping strategies (managing emotions)?

A
  1. attempting to control the response
  2. humour
  3. reappraisal - “worse things happen at sea”
  4. positive self talk - “it’s bad but i’ve coped before”
  5. resigned acceptance
  6. behavioural disengagement
107
Q

describe this statement — ”I know you feel ok now, but this medication will stop it from getting worse”

A

a statement from a doctor designed to improve adherance to treatment that would address a patient’s illness beliefs

108
Q

ABCDE mnemonic for the primary survey of the ATLS protocol

A 
Airway
Breathing
Circulation
Disability
Exposure
109
Q

what is a catamenial pneumothorax?

A

pneumothorax caused by endometriosis in a woman at the time of menstruation

110
Q

what enzyme breaks down noradrenaline molecules after they have been released in a sympathetic synapse?

A

monoamine oxidase

111
Q

what relationships are shown in Hebb’s inverted U?

A

arousal and performance

112
Q

name 4 things you get as a result of PTSD

A
  • feeling of detachment from the outside world
  • re-experiencing of events
  • cannot recall important parts of the trauma
  • hyper vigilance = the elevated state of constantly assessing potential threats around you
113
Q

during normal inspiration what alveolar pressure is required to draw in 0.5L of air?

A

-1mmHg

114
Q

what is the anatomical dead space respiratory volume of a young male?

A

150ml

115
Q

how many broncho pulmonary segments does the right superior lobe contain?

A

3

116
Q

adrenaline lowers cAMP levels by acting on what adrenergic membrane receptors?

A

a2

117
Q

a pulse rate over what suggests a tension pneumothorax?

A

135bpm

118
Q

what are the borders of the safe triangle used when inserting a chest drain?

A
  • apex below axilla
  • horizontal level of nipple
  • lat dorsi
  • pec major
119
Q

what is a suitable first-line treatment for PTSD?

A

eye movement desensitisation and reprocessing

120
Q

activation of what class of neurotransmitter receptors could lead to peripheral vasoconstriction?

A

a receptor

121
Q

chest drains are best placed in which region of the thorax?

A

between 5th and 6th ribs mid axillary line

PBL SEM 2 (44 decks)

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