Sleep Flashcards

1
Q

what is sleep?

A

Normal, recurring reversible state

Loss of ability to respond to external environment

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2
Q

are you conscious or unconscious during sleep?

A

not conscious - as not fully aware of self and environment

but not unconscious as can respond when stimulated

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3
Q

what happens in non-REM sleep?

A

Synchronised rhythmic EEG activity, partial muscle relaxation of muscles, reduced cerebral blood flow
Reduced heart rate, blood pressure and tidal volumes
Some non-narrative images
Often causes you to wake up suddenly, not quite remembering what happened, with a strong emotion

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4
Q

when does non-REM sleep usually occur and how much of sleep does it make up?

A

more at start of night

3/4 of sleep in young adults

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5
Q

features of REM sleep?

A

EEG shows fast activity, fMRI shows increased brain activity (similar to wakefulness)
Atonic muscles (except diaphragm and extraocular muscles)
Cerebral blood flow increases, impaired thermal regulation
Narrative dreaming

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6
Q

when does REM sleep occur and what is its function?

A

mostly at end of night
mainly for early brain development
dispensable sleep

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7
Q

what type of sleep is most important?

A

Non-REM sleep
REM sleep only really important in childhood
Deep sleep is essential sleep
Only part of lost sleep regained after sleep loss
allows cortex to recover after long day

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8
Q

how do sleep patterns differ in young and elderly?

A
neonates
- sleep 16 hrs per day (50% REM)
children (1st decade)
- reduced REM
- increased REM latency
- sleep earlier and wake later
adolescents
- delayed sleep pattern (sleep and wake later)
elderly
- sleep and wake earlier
- increased awakenings
- reduced REM latency and total sleep time
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9
Q

what 3 things contribute to causing onset of sleep?

A
homeostatic response (longer time awake = more sleepy)
emotional response (brain has to be prepared for bed, feeling unrefreshed after long sleep as brain doesn't really switch off, remains in semi-vigilant state)
circadian rhythm
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10
Q

what is circadian rhythm?

A

2 peaks of sleepiness in a day (4-6AM and 2-4PM)
important for sleep-wake, appetite and hormone secretion
normal rhythm lasts 24-25 hrs

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11
Q

what influences circadian rhythm and body clock?

A

bright light
retinal ganglion cells projecting to suprachiasmic nucleus
non-rod and non-cone cells involved

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12
Q

how does psychology control sleep?

A

it doesn’t

biology and psychological factors control sleep

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13
Q

how does sleep influence exercise?

A

sleep deprivation causes reduced endurance (due to psychological factors)
GH release and cell division peaks in sleep

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14
Q

how does sleep influence muscle recovery and tissue repair?

A

doesn’t affect muscle recovery

helps tissue repair

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15
Q

how does sleep affect brain?

A

cortex cannot fully reset when awake

more complicated cortices require more sleep to reset

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16
Q

how can lack of sleep effect the prefrontal cortex?

A

no psychoses but often become irritable and suspicious
visual illusions
microsleeps and concentration lapses

17
Q

does lack of sleep affect prefrontal functioning?

A

no

deals with old and well rehearsed tasks and routine behaviour

18
Q

how is sleep deprivation most likely to kill you?

A

human error

- e.g road accidents

19
Q

how much sleep is adequate?

A

7-7.5 hrs hrs is acceptable (minimum)
A mid afternoon nap of 15 mins is equivalent to 90 mins overnight (best to be around 2pm)
Long lie at the weekend will not make up for chronic sleep deprivation during the week

20
Q

features of REM parasomnia?

A

Body not relaxed as it should be in REM, so body acts out dreams
Much simpler behaviour
Usually latter 1/3 of night
Often have preceding parkinsons

21
Q

features of non-REM parasomnia?

A

non-dreaming

causes confusional arousal, sleep walking, sleep terrors and paralysis

22
Q

give an example of non-REM parasomnia and why this occurs?

A

waking up suddenly to a loud noise and body reacts/jumps up but you don’t really remember doing it
due to fact that primitive part of brain wakes up first

23
Q

what is narcolepsy?

A

REM behavioural disorder

24
Q

features of narcolepsy?

A

severe daytime sleepiness (involuntary and during eating/talking etc)
cataplexy
hypnagogic hallucinations (hallucinations at sleep onset)
sleep paralysis
RBD

25
Q

how is narcolepsy diagnosed?

A
polysomnography
multiple sleep latency test
- fall asleep in 10 mins
- very fast onset of REM sleep)
lumbar puncture (low CSF hypocretin levels)