Sleep Flashcards
Define: sleep
A regularly occurring ASC that typically occurs naturally and is primarily characterised by a loss of conscious awareness.
In what ways can sleep be deliberately induced?
By drugs (eg. medication) and alcohol
Define: sleep cycle
A period of NREM sleep followed by a period of REM sleep.
How long is a typical sleep cycle?
80-120mins
How many sleep cycles are usually experienced during an 8 hour night?
4-5
Describe the patterns of NREM and REM sleep across the night.
NREM sleep gets shorter, and less time is spent in stage 3 and 4 (especially after the first 2 cycles)
REM sleep gets longer.
What proportion of sleep is NREM/REM?
80%/20%
How light/deep is stage one NREM sleep?
Very light
Can a person be woken easily in stage one NREM sleep?
Yes; the might not believe they had fallen asleep
How long does a person spend in stage one NREM sleep?
5-10mins
Describe the EEG, EOG and EMG patterns in stage one NREM sleep.
EEG: alpha waves are being replaced by theta waves
EOG: slow, gentle rolling eye movements
EMG: moderate to low activity; may experience hypnic jerks
The hypnagogic state is experienced in stage one NREM sleep. Define: hynpagogic state
the transition between being awake and asleep, characterised by vivid images including falling and slipping
Hypnic jerks are experienced in stage one NREM sleep. Define: hypnic jerks
Involuntary muscle spasms as a result of the muscles relaxing.
How light/deep is stage two NREM sleep?
Light; we are truly asleep.
Can a person be woken easily in stage two NREM sleep?
Somehwat, not as easily as stage one.
The brain may respond to external stimuli (represented by K-complexes) but may not wake up.
Define: K complex
Bursts of low frequency and high amplitude waves in response to arousing (internal or external) stimuli.