3.05 - Sleeping On The Job - Sleep Apnoea, Respiratory Failure

Front 1

Which activities are influenced by the circadian system?

Back 1

Sleep-wake timing, thermoregulation, respiratory function, cardiovascular function, alertness, neurocognitive performance, immune function, endocrine function, gastrointestinal function, renal function

Front 2

Where is the central circadian pacemaker located?

Back 2

Suprachiasmatic nuclei (SCN) of the anterior hypothalamus

Front 3

What is the strongest environmental time cue synchronising the circadian system?

Back 3

exposure to light-dark cycle

Front 4

How does phototransduction from the retina to the SCN occur?

Back 4

From photoreceptor cells (they are found amongst the cones and rods in the retina) to the SCN via the retinohypothalamic tract (RHT)

Front 5

Name some zeitgebers (external cues that synchronise endogenous time-keeping system) apart from light-dark cycle.

Back 5

melatonin, exercise, social cues

Front 6

When is sleep propensity highest?

Back 6

During the falling phase of core body temperature, melatonin secretion etc at bout 4am.

Front 7

What is melatonin?

Back 7

Indoleamine produced and secreted by the pineal gland (outside of BBB), helps regulates the circadian rhythm and is secreted in darkness.

Front 8

What is melatonin synthesis inhibited by?

Back 8

Suppression of sympathetic neurons originating in the SCN, which occurs in daylight and is caused by neurons from the retinohypothalamic tract.

Front 9

bright light administration prior to the nadir/trough in core body temperature (approximately 8pm-2am) will produce...

Back 9

a phase delay, i.e. preferred wake up and bed sleep time will be shifted to a later time the next day

Front 10

bright light administration after the core body temperature nadir/trough up to about 2 hours after waking will produce...

Back 10

a phase advance i.e. prefer to wake up and sleep at an earlier time the next day.

Front 11

what is the parasympathetic effect on the pupil?

Back 11

pupil constriction

Front 12

what is the sympathetic effect on salivary glands?

Back 12

saliva reduced

Front 13

what percentage of cardiac output supplies blood to the lung tissue?

Back 13

1-2%

Front 14

what is the pulmonary artery pressure?

Back 14

25/10 mmHg

Front 15

what is the pumonary vein pressure?

Back 15

1-3 mmHg

Front 16

where are pressures lowest, the top or bottom of the lungs?

Back 16

apex of lung

Front 17

where is blood flow highest in the lung?

Back 17

base

Front 18

what type of epithelium lines the nasal cavity?

Back 18

respiratory and olfactory epithelium (pseudostratified columnar and squamous)

Front 19

name the paranasal sinuses

Back 19

frontal, ethmoidal, sphenoidal, maxillary

Front 20

what type of epithelium lines the paranasal sinuses?

Back 20

respiratory epithelium (pseudostratified columnar)

Front 21

which nerve/s is/are sensory to the external nose?

Back 21

V1, V2

Front 22

what is the motor supply to the external nose?

Back 22

VII, Facial

Front 23

what is the sensory supply to the nasal cavity?

Back 23

Vi, V2 and I(smell receptors)

Front 24

what is the parasympathetic ganglion associated with the nasal cavity?

Back 24

pterygopalatine ganglion

Front 25

which cranial nerve synapses in the pterygopalatine ganglion to give parasympathetic supply to the paranasal sinuses?

Back 25

facial

Front 26

which muscle retracts the tongue?

Back 26

styloglossus

Front 27

which muscle raises the tongue?

Back 27

palatoglossus

Front 28

which muscel raises the soft palate?

Back 28

levator veli palatini

Front 29

which muscle tenses the soft palate?

Back 29

tensor veli palatini

Front 30

which muscle protrudes the tonge?

Back 30

genioglossus

Front 31

which muscle depresses the tongue?

Back 31

hyoglossus

Front 32

what are the actions of the intrinsic tongue muscles?

Back 32

raise/depress tip, narrow, elongate, flatten

Front 33

which artery travels in the parotid gland?

Back 33

external carotid artery

Front 34

which nerve travels in the parotid gland?

Back 34

facial

Front 35

which salivary gland is located underneath the mandible, close to the symphysis?

Back 35

sublingual

Front 36

what is the sensory innervation of the mouth?

Back 36

V2, V3

Front 37

what is the parasympathetic innervation of the mouth?

Back 37

VII-Pterygopalatine ganglion

Front 38

what is the sensory innervation of the tongue?

Back 38

V3

Front 39

what is the sensory innervation of the palate?

Back 39

V2

Front 40

which cranial nerves contain taste fibres?

Back 40

VII and IX

Front 41

what is the parasympathetic innervation of the tongue?

Back 41

VII (submandibular ganglion)

Front 42

what is the parasympathetic innervation to the palate?

Back 42

VII-ptergopalatine ganglion

Front 43

what innervates levator veli palatini?

Back 43

X-XIc

Front 44

what innervates palatoglossus?

Back 44

X-XIc

Front 45

what innervates tensor veli palatini?

Back 45

V3

Front 46

which muscle of the soft palate is innervated by X-XIc?

Back 46

levator veli palatini

Front 47

which muscle of the soft palate is innervated by V3?

Back 47

tensor veli palatini

Front 48

which tongue muscle is innervated by X-XIc?

Back 48

palatoglossus

Front 49

what innervates most of the tongue muscles?

Back 49

XII

Front 50

what is the parasympathetic innervation of the parotid gland?

Back 50

IX (otic ganglion)

Front 51

which salivary glands receive parasympathetic supply via VII (submandibular ganglion)?

Back 51

submandibular and sublingual

Front 52

which muscles form the faucial arches and what is their innervation?

Back 52

palatopharyngeus, palatoglossus (both innervated by X)

Front 53

What percentage of Australians suffer from chronic sleep disorders?

Back 53

20%

Front 54

where is the lesion in the somnolent type of encephalitis lethargica?

Back 54

posterior hypothalamus

Front 55

which type of encephalitis lethargica is associated with lesions of the preoptic area and basal forebrain?

Back 55

insomnia type

Front 56

where are the neurons that promote wakefulness?

Back 56

poasterior hypothalamus (tuberomamillary nucleus)

Front 57

where are the neurons that promote sleep?

Back 57

preoptic area (ventrolateral preoptic nucleus)

Front 58

what in the brain controls circadian rhythms?

Back 58

suprachiasmatic nucleus

Front 59

what secretes melatonin?

Back 59

pineal gland

Front 60

what percent of the night is spent in REM sleep?

Back 60

20-25%

Front 61

which stage of sleep accounts for the greatest percentage of the night?

Back 61

NREM 2

Front 62

t/f... NREM thought is logical and not remembered

Back 62

true

Front 63

what are the criteria for REM sleep?

Back 63

EEG activation, muscle atonia, episodic bursts of rapid eye movements

Front 64

what is the prevalence of insomnia?

Back 64

30-40%

Front 65

t/f... insomnia is more likely in men

Back 65

false, insomnia is 1.5 times more likely in women

Front 66

what percentage of men have obstructive sleep apnoea syndrome?

Back 66

4%

Front 67

what percentage of men have obstructive sleep apnoea?

Back 67

24%

Front 68

what percentage of women have OSA?

Back 68

9%

Front 69

what percentage of women have OSA syndrome?

Back 69

2%

Front 70

what is the prevalence of narcolepsy?

Back 70

0.02 - 0.18%

Front 71

t/f... sleep episodes in narcolepsy are not refreshing

Back 71

false

Front 72

which muscles are affected by cataplexy?

Back 72

all striated muscles

Front 73

what happens to CSF orexin levels in narcolepsy?

Back 73

low or absent

Front 74

what is bruxism?

Back 74

grinding or clenching of teeth during sleep

Front 75

for OSA syndrome to be diagnosed, what is the RDI?

Back 75

> 5 events/hour of sleep

Front 76

when will collapse of the upper airway occur?

Back 76

when the force produced by the muscles is exceeded by the negative airway pressure

Front 77

where does airways obstruction occur in OSA?

Back 77

between choanae and epiglottis, behind uvula and soft palate and behind the tongue

Front 78

how do upper airway muscles repond to negative airway pressure?

Back 78

reflex activation

Front 79

which chemoreceptors detect CO2?

Back 79

central chemoreceptors in the medulla

Front 80

what do the peripheral chemoreceptrs detect?

Back 80

O2

Front 81

where are the peripheral chemoreceptors located?

Back 81

carotid body

Front 82

where do pathological changes in emphysema occur?

Back 82

distal to terminal bronchiole

Front 83

t/f... emphysema involves overinflation of alveoli

Back 83

false

Front 84

which deficiency is associated with emphysema?

Back 84

alpha1 anti-trypsin

Front 85

what does alpha1 anti-trypsin do?

Back 85

inhibits proteases (elastase, collagenase)

Front 86

how does cigarette smoking lead to a deficiency in alpha1 anti-trypsin?

Back 86

oxidants from cigarettes inhibit alpha1-AT

Front 87

which cells secrete proteases which contribute to emphysema in smokers?

Back 87

neutrophils and macrophages

Front 88

what are the three features of chronic bronchitis?

Back 88

1) productive cough >3 months/year for 2 consecutive years
2)excessive mucous
3) infection

Front 89

what are some pathological changes in chronic bronchitis?

Back 89

vascular congestion, mononuclear inflitrate, thickened basement membrane, abundant mucous-secreting cells

Front 90

which cells have a clock face appearance?

Back 90

plasma cells

Front 91

what is a normal reid index?

Back 91

<0.4

Front 92

what is the reid index in chronic bronchitis?

Back 92

>0.4

Front 93

what is the critical feature of emphysema?

Back 93

loss of elastin

Front 94

What is the circadian system?

Back 94

homeostatic system that coordinates behaviours, regulates timing of sleep wake duration, cognition, performance awareness. rhythm is for about 24 hours

Front 95

What happens in the circadian system in depression?

Back 95

Mood is worse upon waking, gets better through day (opposite to normal functioning)

Front 96

What are clock neurons?

Back 96

throughout body, regulated by SCN,

Front 97

What is night eating syndrome?

Back 97

separation of SCN from clock neurons in body, therefore oscillate at different frequency to SCN, and hunger doesn't match up with time of days

Front 98

When is the strongest signal to be awake?

Back 98

just before going to bed, 8 or 9 pm

Front 99

When is the strongest signal to be asleep?

Back 99

just before waking

Front 100

What is sleep debt or pressure?

Back 100

The concept that our sleep debt/pressure is zero upon waking, sleep debt/sleepiness rises throughout the day, and is paid off by sleeping at the end of the day. It may be due partly to adeonsime accumulating in awake times acting on A1 receptors in the brain.

Front 101

How is slow wave sleep stage amount regulated?

Back 101

Slow wave sleep is driven by sleep debt therefore more of it early in the night. Driven by homoeostatic sleep system.

Front 102

How is REM sleep stage amount regulated?

Back 102

REM is circadian driven, shorter in the earlier of the night, more in the later period of morning, especially if you attempt to sleep in (you will find yourself having more vivid dreams and remembereing them better). Circadian driven

Front 103

What is wrong with being asleep during the day such as found in shift work were you must sleep during the day?

Back 103

Sleep when core body temperature is high, therefore lighter sleep, more REM in start abd less later on (reversed), less slow wave sleep therefore sleep debt not paid back, less refreshing, poorer quality, wake up tired

Front 104

How many people are shift workers?

Back 104

~25%

Front 105

What are the effects of shift work on health?

Back 105

Increased mortality, increased CVS events, higher incidence for diabetes, higher cortisol, reduced immune function, changes in metabolism, changes in appetite and hunger

Front 106

What are the effects to work ability in shift workers?

Back 106

decreased concentration, reduced memory, decreased ability to judge impairment, increased sleepiness, increased accidents, slower reaction times, performance gets worse

Front 107

t/f... sleep deprivation can be adapted to over time

Back 107

false, studies show that you get worse and worse until the sleep debt is paid off i.e. going 2 weeks with only 4 hours sleep can be equivalent to going 48 hours without sleep in terms of performance

Front 108

What time of the day is associated with the highest asleep crashes and why?

Back 108

7am - 8am (but it is slowly rising from about 11pm the night before) There is also a secondary post-prandial dip in the afternoon at approximately 2pm.

Front 109

How many fatalities are fatigue related?

Back 109

estimated ~20%

Front 110

How much does an increase from working 65 to 85 hours a week increase error risk in interns?

Back 110

20% higher overall (some of them very serious mistakes...)

Front 111

t/f... being awake for 18 hours impairs hand-eye coordination a similar amount to a blood alcohol of 0.05

Back 111

true

Front 112

t/f... the more sleep that you can have in a day, the better the effects on your health

Back 112

false, there is a happy-medium at around 8 hours, >9 hours is associated with increased mortality even more so than sleeping < 5 hours.

Front 113

What stage of sleep is slow wave sleep, and how much of the sleep cycle does it take up?

Back 113

Stage 3 and 4 or also known as N3, 20%

Front 114

Describe the electrical, eye and muscle movements in stage 1 sleep?

Back 114

N1
slower AP than awake, rolling eye movements, slightly reduced muscle tone to awake.

Front 115

Describe the electrical, eye and muscle movements in stage 2 sleep?

Back 115

N2
spindle/k complexs on EEG, no eye movement, slightly reduced muscle tone

Front 116

Describe the electrical, eye and muscle movements in stage 3 sleep?

Back 116

Slow wave sleep, N3
20-50% waves are 75uV in amplitude, frequency less than 4/sec, no eye movement, slightly reduced muscle tone

Front 117

Describe the electrical, eye and muscle movements in stage 4 sleep?

Back 117

Slow wave sleep, N3
>50% waves at 75uV, frequency less than 4/sec, no eye movement, muscle tone slightly reduced

Front 118

Describe the electrical, eye and muscle movements in REM sleep?

Back 118

small amplitude mixed frequency with possible sawtooth waves which resembles awake with eyes open, rapid eye movements in opposing directions, lowest muscle tone

Front 119

At what stage in life does SWS dominate the sleep cycle?

Back 119

young children, decreases with age, associated with sleepwalking and night terrors becoming less frequent?

Front 120

What 2 things will cause a phase delay in the circardian rhythm?

Back 120

Bright light in the evening, melatonin in the morning

Front 121

What 2 things will cause a phase advance in the circadian rythm?

Back 121

Melatonin in the evening, bright light in the morning.

Front 122

What neurotransmitter is used in the anterior hypothalamus to promote sleep system?

Back 122

GABA

Front 123

What hormones/transmitters are used in posterior hypothalamus nuclei to promote wakefulness?

Back 123

Ach and monoamines, orexin/hypocretin maintains stability of wake state too

Front 124

What is the definition of respiratory failure?

Back 124

PAO2 <60mmHg (at rest)

Front 125

What are the 2 patterns of respiratory failure?

Back 125

Type A /I= Pink puffer, low O2, normal CO2

Type B/II - Blue Bloater, low O2, low CO2

Front 126

Blood gases normal results for:
-PaO2
-PaCO2
-Ph
-Base Excess
-Bicarbonate

Back 126

>95-100
40
7.4
0
26

Front 127

What happens to PACO2 and PAO2 in hypoventiliation ?

Back 127

If decreased ventilation, CO2 goes up, O2 goes down.

Front 128

What are causes of low PAO2?

Back 128

Hypoventilation
VQ mismatch
shunt (blood doesn't go to lungs)
diffusion defect (fibrosis etc)
ow inspired oxygen % pressure (altitude)

Front 129

How is breathing controlled centrally?

Back 129

Medullary, CO2 detectors (want PH to stay constant), linear response

Front 130

How is breathing controlled peripherally?

Back 130

At bifurcation - Carotid body, O2 detectors (influenced by CO2), linear response (saturation of O2)

Front 131

What happens when CO2 rises in the body?

Back 131

Ventilation increases.

Front 132

What colour is oxygenated haemoglobin and deoxygenated haemoglobin?

Back 132

deoxygenated Hb - blue
oxygenated - bright red

Front 133

What happens to Hb when pAO2 is <60mmHg?

Back 133

as Hb is saturated with O2 at >60, when below, it pushes O2 off to go to muscles

Front 134

What are some sinks for CO2?

Back 134

bicarbonate, amino acids, ammonia

Front 135

What is the alveolar gas equation?

Back 135

Tells you if low O2 is due to hypoventilation or VQ mismatch by comparing PACO2/O2 levels.

A-a gradient =150- pO2 – (1.25 x pCO2)

>20 = impaired diffusion, VQ mismatch

Front 136

What is an apnoea?

Back 136

cessation of airflow at nose and mouth >10 sec, during sleep

Front 137

What is hypopnoea?

Back 137

reduced airflow or >50% reduction in thoracoabdominal movement, >10 sec, associated with an arousal or O2 decrease >3%

Front 138

What is a central apnoea?

Back 138

Effort to breath is lost due to central fault.

Front 139

What is obstructive apnoea?

Back 139

Effort to breath is made (though lesser), but obstruction prevents breathing.

Front 140

OSA definition?

Back 140

REcurrent upper airway obsturction in sleep, spectrum, sleep study showing >5 events/hr, fnl impairment = daytime sleepiness + chocking/unrefreshing sleep/waking nocturnally/impaired concentration,

Front 141

Consequences of OSA

Back 141

hypersomnolence, decreased gognition, memory,.emontional disturbances
Decreased oxyhaemoglobin sat, hypertention, arrhythima, atrial fibrillation, infarction, stroke, hypercapnic ventilatory response

Front 142

Cause of OSA?

Back 142

Low muscle tone of upper airway
anatomical narrowing
defective reflex (damage to sensing - pressure)
increase loop gain
frequent arousals

Front 143

Site of OSA?

Back 143

soft palate and tongue closure

Front 144

Risk factors for OSA?

Back 144

Males, hormonal?, aged, obesity****, genetics, EtOH, small jaw, enlarged tonsils, infiltration of muscles and soft tissues (large tongue), nasal obstruction

Front 145

What is bad about a smaller airway?

Back 145

Resistance increases greatly with decrease to radius (to power of 4), - pressure increases within narrowed airway, contributing to collapse of airway

Front 146

What are the muscles involved in OSA?

Back 146

tensor veli palatini = tense, pull, sit on tongue, promotes nasal breathing******
levator veli palatini = elevates in swallowing, block nasopharynx
palatoglossus and palato pharyngeus - lower and close palate to promot nasal breathing

Front 147

What occurs to the negative pressure reflex in the airways in sleep?

Back 147

It is turned off/reduced, so that the reflex which kept their airway patent in wake is no longer present

Front 148

What are the two types of central sleep apnoea?

Back 148

Low respiratory drive and High respiratory drive.

Front 149

What is the symptom of cardiac failure central apnoea?

Back 149

waxing and waning breathing, delayed circulation and fluctuation of PACO2 sensed in cerebel cortex (Cheyne Stokes breathing)