L3- Sleep Flashcards
what is sleep
Not just the absence of consciousness
sleep is recognised as
essential- absence results in death e.g. fatal familial insomnia
Lack of sleep can cause
low mood but conversely in some people hypomanic or manic like symptoms
sleep is a balance between
circadian rhythm and sleep pressure
circadian rhythm
- Natural fluctuation in body functions
- Levels of hormones, body temp etc.
- Lower in the night, lowest between 4-5am (most mistakes made)
sleep pressure
the pressure to go to sleep
what creates sleep pressure
Build up while awake of adenosine, higher levels greater sleep pressure
Breakdown when asleep
Caffeine temporarily blocks the receptors
sleep occurs in
90 min cycles with periods of waking
rapid eye movement (REM sleep)
- Associated with dreaming
- Rapid erratic neural patterns-similar to awake without sensory input
- Strengthens connections in the brain
- Alcohol suppresses REM sleep
stages of sleep
Non-REM (NREM) sleep (Stages 1, 2 & 3) and REM sleep.
stage 1 (1-10 mins)
is the lightest stage of NREM sleep. Often defined by the presence of slow eye movements, this drowsy sleep stage can be easily disrupted causing awakenings or arousals. Muscle tone throughout the body relaxes and brain wave activity begins to slow from that of wake. Occasionally people may experience myoclonic jerks or abrupt muscle spasms and may even experience sensation of falling while drifting in and out of Stage 1.
stage 2 (2-20 mins)
decreased heart rate, decrease temp (45%sleep)
stage 3
s known as deep NREM sleep. The most restorative stage of sleep, stage 3 consists of delta waves or slow waves. Awakenings or arousals are rare and often it is difficult to awaken someone in Stage 3 sleep.
REm stage
REM sleep, also known as rapid eye movement, is most commonly known as the dreaming stage. Eye movements are rapid, moving from side to side and brain waves are more active than in Stages 2 & 3 of sleep. Awakenings and arousals can occur more easily in REM; being woken during a REM period can leave one feeling groggy or overly sleepy.
more ….. earlier, more …. later
NREM
REM
melatonin (vampire hormone)
Regulates sleep/wake cycle also an antioxidant/possibly anti-inflammatory
where is melatonin produced
pineal gland
melatonin is regulated by
activation of B1 adrenergic receptors
daylight stops
noradrenergic stimulation affecting enzyme production
blue light
suppresses melatonin production
bananas
increase blood melatonin
sleep cycles vary with age
teenagers have later onset of melatonin
larks
40% early morning wakefulness
owls
30% wake more in evening and later
