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Z MD1 Respiratory block > Physiology > Flashcards

Flashcards in Physiology Deck (97):
1

definition of sleep

a behavioural state characterized by decreased awareness of external environment, decreased reactivity to stimuli, but with the capability to return rapidly to wakefulness.

1

association between sleep deprivation and

- mortality and morbidity - decreased cognitive function

2

in general, an elevated PCO2 is due to

inadequate alveolar ventilation

3

infective exacerbations of COPD are caused by what

bacterial bronchitis increased bronchospasm

4

how long does oxygen require to fully saturate in the lungs

0.25 seconds

4

mechanical effects of restrictive lung diseases

- breathlessness - increased work of breathing - reduced lung volumes - altered pattern of breath - reduced maximum ventilation

4

complications of asthma

- death - atelectasis - pneumothorax - airway remodelling - irreversible obstruction - chronic hypoxia --> pulmonary hypertension --> cor pulmonale

4

brainwave change, EMG change and EOG change from NREM to REM

EMG paralysed (inhibited) EEG becomes more desynchoronized EOG - rolling eye movements

5

clinical signs of pulmonary hypertension and RVH

- right ventricular heave - loud P2 and 4th heart sound - increased JVP with v waves

6

how does emphysema cause airway obstruction

due to loss of elastic recoil

6

what is the main regulator of breathing during sleep

chemical control (central and peripheral chemoreceptors)

7

what other sensors (other than chemoreceptors) contribute to breathing

- pulmonary stretch receptors - irritant receptors - J receptors - upper airway receptors - joint and muscle receptors - pain

7

what is the compensatory mechanism elicited by the lungs when there is low ventilation

vasoconstriction - directs perfusion away

7

what does the ventrolateral preoptic nucleus do

inhibits the arousal centres - sleep until the arousal centres get the upper hand - inhibit the VLPN - prevents sleep

8

summary of gas exchange and mechanical effects of restrictive lung diseases

- increased sensation of breathing - increased elastic WOB - reduced lung volumes - altered pattern of breathing - reduced maximum ventilation - abnormal gas exchange, which worsens with exercise

8

when do we do most of our deep sleep and most of our REM sleep

deep sleep - first part of the night REM - second half of the night

9

volume of CO2 and O2 removed/ produced per minute

200 ml/min CO2 250 ml/min O2

10

what are the physiological effects of disrupting the A-C membrane?

- abnormal gas exchange - abnormal lung mechanics - pulmonary vascular complications

10

pathogenesis of chronic bronchitis

chronic irritation by inhaled substances causes increased mucus production in the larger airways (due to hypertrophy of mucus secreting glands and increased goblet cells) and airway inflammation, scarring and narrowing in the smaller airways

11

what do central chemoreceptors respond to

H+ do not respond to oxygen!

11

Ventilation and arterial CO2, O2 and pH during metabolic acidosis

Ventilation is excessive for oxygen consumption PaO2 >100 PaCO2

13

What is ficks law

the rate of diffusion is proportional to the surface area, the constant, and the difference in partial pressures, and inversely proportional to thickness

14

in general, elevated PaCO2 is due to

inadequate alveolar ventilation

15

what is the function of orrexin

stabilises the arousal system

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why does the WOB increase in restrictive diseases

because the inspiratory muscles need to generate higher pressures to overcome the reduced compliance of the lungs --> leading to recruitment of accessory muscles, increased oxygen consumption by respiratory muscles and risk of respiratory muscle fatigue if airway obstruction is severe

18

basal rates of CO2 and O2 (ml/min)

CO2 production - 200 ml/min O2 use - 250 ml/min

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surface area of alveolar capillary membrane

50-100 m2

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what drives circadian rhythms

the suprachiasmatic nucleus

20

thought during wake, NREM and REM

W - logical, progressive NREM - day dreamy REM - illogical, bizzare

21

main causes of increased capillary hydrostatic pressure

Left ventricular dysfunction mitral stenosis fluid overload pulmonary veno-occlusive disease

21

what happens to CO2 with sleep

at onset - decreased drive - decrease in minute ventilation - leads to increase in CO2 - stimulates breathing - equilibrium reached (but CO2 slightly higher than wakefulness)

23

what are the forces that inspiration has to overcome

resistive - airflow through bronchi elastic - expansion of lungs and chest wall

24

2 major arousal systems acting on the cerebral cortex and thalamus

cholinergic ascending system - affects the thalamus monoaminergic system - innervates the cortex

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what happens to ventilatory components during anxiety

VE excessive for oxygen consumption PaO2 >100 PaCO2

27

thickness of alveolar capillary membrane

0.5 microns

28

how does smoking cause emphysema

- draws in inflammatory mediators - neutrophils release proteases that break down elastin - inhibition of anti-proteases

30

what tells you (from lung function test) that a patient is gas trappin

high TLC, RV and RV/TLC

31

why doesnt the pulmonary artery pressure increase during exercise in a normal person

due to recruitment and dilatation of pulmonary vessels

31

mechanisms to increase pulmonary vascular resistance

- VASOCONSTRICTION = chronic hypoxia --> vasoconstriction (spasm of SM) --> diverts blood through just a few vessels so increases the pressure - OBLITERATION= chronic inflammation --> destruction of alveoli and BVs due to fibrosis --> volume of capillar

32

definition of bronchiectasis

irreversible, abnormal dilatation of bronchi/bronchioles

33

how many sleep cycles are typical per night

4-6

34

mean pulmonary artery pressure

15 mmHg

35

definition of chronic bronchitis

clinical definition persistent cough productive of sputum for at least 3 months in 2 consecutive years for which no other cause can be identified

35

how long is a typical sleep cycle

90-120 minutes

36

typical sleep requirement of infants

up to 18 hours

38

pneumonic for causes of disease and each meaning

I DIVINE TIME Congenital/Genetic Acquired: - Infectious - Degenerative - Inflammation/Immune reactions - Vascular - Iatrogenic (drugs, surgery, radiotherapy) - neoplastic - environmental - trauma - idiopathic - metabolic - endocrine

39

whee does laminar and turbulent flows occur

laminar - in small airways (poiseulles law applies - 8nl/pi x r4 turbulent - during high flows (large airways)

40

normal lymphatic flow from the lungs

20ml/hour

41

definition of asthma and then simplified definition

- increased responsiveness of the airways to various stimuli leading to episodic bronchoconstriction which is at least partly reversible - reversible bronchoconstriction

42

main obstructive lung diseases

COPD - chronic bronchitis, emphysema, small airway disease asthma bronchiectasis

43

normal range for HCO3

22-28

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main causes of increased capillary permeability

toxins sepsis multiple trauma aspiration of gastric acid

46

complications of chronic bronchitis

- superimposed infective exacerbations - hypoxia, pulmonary hypertension, cor pulmonale - squamous metaplasia --> squamous dysplasia - premalignant

47

reasons for breathlessness (broadly)

respiratory cardiac muscle weakness metabolic anaemia psychogenic

48

how long is the Hb in contact with the blood-gas barrier at rest

0.75 seconds

49

pathophysiology of asbestosis

progressive, diffuse inflammation and fibrosis of lung parenchyma causing disruption and destruction of the A-C membrane

50

Obstructive and restrictive lung diseases are a group of lung diseases which are:....

chronic, diffuse and non-infectious

50

what happens at anaerobic threshold

- disproportionate increase in VE for work - causes PaCO2 to decrease and pH to drop slightly due to lactic acid production

51

1 gm combines with how much O2

1.3 ml O2

53

What does ARDS cause

- type 1 respiratory failure due to low V/Q units and shunt and stiff lungs

54

diseases that can disrupt the A-C membrane

- inflammation - infection -fibrosis -emphysema -fluid -cancer

56

what do peripheral chemoreceptors respond to

reduced oxygen, reduced pH, increased CO2

57

over a long period, people with severe OSA can develop...

(chronic hypoxia, chronic hypercapnea, and compensated respiratory acidosis (HCO3- is high) Re-setting of the respiratory centre --> day time hypoventilation)

58

main 2 reasons thought for why we need sleep

brain development repair and maintenance

59

what happens to the controllers of breathing during sleep

loose higher centres, emotional drive and non-specific inputs other inputs downregulated significantly

61

definition of emphysema

abnormal, permanent enlargement of air spaces distal to the terminal bronchiole (from destruction of the alveolar wall without fibrosis)

62

what are the effects of pulmonary oedema

-mechanism changes - (decreased compliance, restrictive ventilatory defect, increased airway resistance and increased WOB) - reduced gas exchange - due to shunt, low V/Q and diffusion impairment - increased pulmonary vascular resistance

64

rate of diffusion is determined by

Ficks Law

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symptoms of OSA

- snoring - witnessed apnoeas - arousals - choking - mood change, poor memory, decreased libido - difficult to treat HT, unexplained RF

66

what do you do/feel as a result of increased airways obstruction

-increased sensation of breathing - increased respiratory muscle effort - active exhalation - prolonged inspiration and expiration - altered pattern of breathing - reduced maximum ventilation - sometimes gas trapping

67

what defines obstruction via spirometry

FEV1/FVC lower than 80% in younger and 70% in elderly

69

compliance of the lungs is effected by:

- tissue composition - surface tension in alveoli

71

5 functions of the lungs

1) protect the heart from physical trauma 2) act as a flotation device 3) oxygenate pulmonary arterial blood 4) remove carbon dioxide from blood 5) maintain acid-base balance

72

what causes restrictive lung diseases

inflammation and fibrosis of inter-alveolar septa

73

definition of breathlessness

RECOGNITION by the subject of an INAPPROPRIATE relationship between RESPIRATORY WORK and TOTAL BODY WORK

73

what does the Suprachiasmatic nucleus do

- receives input from rods, cones and meanopsin - receives input from the intergeniculate leaflet of the lateral geniculate thalamic nulceus - projects to the paraventricular nucleus which connects with the pineal gland which secretes melatonin

74

causes of hypoventilation (5)

- reduced respiratory centre activity - neuromuscular disease - chest wall deformity - gross obesity - SDB

74

main components controlling breathing

- medulla - inflation reflex - peripheral stimuli (pain, touch, temp) - Joint receptors - non-specific drive - central and peripheral chemoreceptors - emotional stimuli

76

how much oxygen in the blood

200ml / Litre

77

what is the sleep centre

ventrolateral preoptic nucleus

78

brainwave change, EMG change and EOG change from W to sleep

EEG more synchornized and lower in amplitude EMG - reduced EOG - slow rolling eye movements

79

pathogenesis of bronchiectasis

- airway gets filled with mucus - infection behind it --> severe destruction of airways and surrounding elastic tissue

81

definition of small airways disease

chronic inflammation, fibrosis and obstruction of terminal bronchioles caused by cigarette smoke

82

definition of OSA

transient obstruction of the throat during sleep preventing breathing, and disturbing sleep

83

causes of pulmonary hypertension

- increased LA pressure - increased pulmonary blood flow - increased pulmonary vascular resistance

85

MUD reasons for dyspnoea

clinical disease diseased or deconditioned psychogenic maximum effort

86

complications of emphysema

- hypoxia (caused by airways obstruction and low DLCO) - pulmonary hypertension --> cor pulmonale - pneumothorax

87

effect of inspiration on cardiovascular system

- decreased venous return to LA - decreased CO - decreased systolic BP on inspiration

89

symptoms of psychogenic breathlessness

- need to take deep inspiration - at rest, but not at exercise - anxiety - tingling in fingers, feet, face or head - oppressive/compressed chest

90

movement during W, NREM and REM

W - continuous, voluntary NREM - move alot REM - commanded but inhibited

91

sensation and perception during wake, NREM and REM

W - vivid, externally generated NREM - Dull or absent REM - vivid, internally generated

92

How do restrictive lung diseases look on xray

ground-glass/reticulo-nodular

93

What are kerley b lines and what are they caused by

dilated interlobular septa caused by dilated lymphatics

94

what is the ratio of increasing HCO3 for increase in CO2

2-3 mmol/L increase in HCO3- for every 10mmHg increase in CO2

95

how does smoking predispose to pulmonary infection

- inhibition of the muco-ciliary esculator - increased mucus - inhibition of leukocyte function - direct damage to the epithelial layer

96

respiratory causes of dyspnoea

airways disease alveolar disease pulmonary vascular disease pleural and chest wall disease respiratory muscle disease

97

effects of sleep deprivation

- cognitive impairment - impaired immune system - risk of diabetes type 2 - increased HRV - risk of heart disease - decreased reaction time and accuracy - tremors -aches - growth suppression - risk of obesity - decreased temp