chronobiology (27) Flashcards
list the percent of time spent in each of the stages of sleep stage 1 stage 2 stage 3&4 REM sleep
stage 1: 6%
stage 2: 49%
stage 3&4: 23%
REM sleep: 22%
how many minutes is each cycle? what is the cycle order?
90 minutes
1-2-3-4-3-2-REM
through out the night, describe what happens to the duration of REM and stage 4 sleep?
REM amount increases throughout the night
stage 4 sleep decreases throughout the night
what type of waves are present in the alert stage?
beta waves
what type of waves are present in the awake stage?
alpha waves
describe the awake stage (compared to the alert stage
“awake stage” is you are awake but drowsy/relaxed
what type of waves are present in stage 1?
theta waves
what stage is considered your lightest sleep?
stage 1
what type of waves are present in stage 2?
sleep spindles & K complexes
what type of waves are present in stage 3?
delta waves
what stage does this describe?
“ deep slow wave sleep”
stage 3
what type of waves are present in stage 4?
delta waves
explain what is occurring in stage 4 sleep
parasymp control, lowered viral signs, restorative sleep
what type of wave is characteristic of REM?
low voltage fast activity (similar to stage 1) or sawtooth pattern
what stages of sleep decrease with age?
stages 3 and 4
what stages increase with age?
1 and 2
where is the melatonin produced?
pineal gland at night
what is melatonin produced in response to?
in response to light induced neuronal firing in the retinohypothalamic tract
what receptor is involved in the lowering of brain activation & arousal?
M1
what receptor facilitates the 24 hour circadian clock?
M2 receptors
what does melatonin do to the sympathetic drive?
suppresses it
when does cortisol peak?
in the morning
where is ACh secreted from?
basal forebrain
what does the GABA secreted from the basal forebrain do?
it inhibits inhibitory neurons in sleep promoting centers to decrease the sleep drive
where is norepi secreted from?
the locus coeruleus
is norepi fired during NREM & REM sleep?
yes but not nearly as much as during wakefulness
what can excessive firing of noepi cause?
it can cause insomnia & anxiety at night
what structure secretes histamine?
tuberomammilary nucleus in the posterior hypothalamus
is histamine secreted during sleep?
yes just not as much as when awake
what happens when you stimulate H1 receptors?
wakefulness
what happens when you stimulate H3 autoreceptors?
histiamine is inhibited
so you have to block H3 if you want wakefulness
what structure secretes serotonin?
the dorsal raphe
what is the action of serotonin?
generally promotes wakefulness & inhibits REM
where is dopamine produced?
in the substantia nigra and ventral tegmental area
what neurotransmitter does this describe:
“may provide motivational arousal as opposed to task oriented alertness”
dopamine
what is special about the orexin/hypocretin system?
it is NOT part of the RAS system
it is part of its own system important in keeping the other systems going
does orexin/hypocretin system fire when you are asleep?
NO, only fire when awake
