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Circadian Rhythms (7)
- body has more than 100
- each unique 24 hour cycle influences an apect of body's function inc:
- temperature
- hormone levels
- heart rate
- blood pressue
- pain threshold
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Suprachiasmatic (2)
- regulates the firing of nerve cells that seem to set your circadian rhythms
- called internal pace-maker
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Zeitgebers
outside influences that influence 24 hour schedule
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Temperature cycle (3)
- lowest temp when inactive
- temp flows at circadian rhythm
- afternoon temp can be 3 degrees higher than morning temp
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Sleep-wake cycle (3)
- sleep patterns follow circadian rhythm
- sleep better when temp is lowest (early am) most likely wake when temp rises (6-8am)
- when elderly suprachiasmatic (internal pace-maker) losses cells, which changed circadian rhythms (noticeable in eldery's sleeping patterns)
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The sleep cycle (3)
- has 5 stages
- each cycle lasts 90 mins, good sleep 4-6 cycles
- first time through cycle spend 10 mins in REM sleep, increases to 30-60 mins by last cycle
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Stage 1 sleep (4)
- brain waves go from beta to alha to theta
- hypnotic jerks
- lasts 10 mins
- transition from relaxed wakefulness too sleep
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Stage 2 sleep (4)
- Sleep spindles - bursts of rapid rhythmic brain wave activity
- body temperature starts to reduce, heart rate begins to slow
- lasts 20 mins
- compared to stages 3 and 4, stage 2 is still light sleep
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Stage 3 and 4 sleep (6)
- Deep sleep (stage 4 more intense)
- Delta waves - deep, slow brain waves
- body repairs and regenerates tissues, builds bone and muscle and appears to strengthen immune system
- when woken from deep sleep feel disorientated and drowsy
- Stage 4 is Deepest stage of sleep
- less time in stages 3 and 4 as night progresses
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Stage 5 sleep (7)
- Rapid Eye Movement
- after reverting back through stages 3 and 2, the brain enters REM sleep
- paradoxial sleep - brain activity increases, but muscles become more relaxed
- Marked by more vivid, detailed and story-like dreams (dream in all stages but these more vivd
- called PARADOXICAL SLEEP
- REM periods lengthen and occur closer together as night progresses
- later period may last an hour - early only few mins
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The pineal gland (2)
- controls circadian sleep-waking cycle
- located near the hypothalamus at the centre of the brain
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Melatonin (3)
- amount present in bloodstream influences how sleepy a person becomes
- higher levels = more sleepy
- secreted amounts varies according to amount of light
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Nrem sleep (3)
- 80% of all sleep is nrem sleep
- brain is active, but not as active as in rem sleep
- contains stages 1 to 4
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Determining Sleep Stages (3)
- Each stage is dominated by a particular identifiable brain wave of rhythm
- frequency = number of brain waves
- amplitude = intensity of brain waves
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Physical side of Stage 1 (8)
- lose awareness of self and surroundings
- lower level of bodily arousal
- decrease in:
- HR
- respiration
- body temp
- muscle tension
- hypnotic jerking
- alpha brain waves turn to theta waves (mixture of high and low amplitude)
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Physical side of Stage 2 (8)
- body movements lessen
- breathing regulates
- blood pressure keeps falling
- temperature keeps falling
- HR is slower
- brain waves are theta waves (slightly lower in frequency and higher in amplitude than those of Stage 1)
- brief bursts of higher frequency brain wave activity called sleep spindles - indicate really asleep
- brain still responds to external stimuli
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Physical side of Stage 3 (9)
- Keep dropping:
- HR
- blood pressure
- body temperature
- breathing keeps slowing and steadying
- person becomes less responsive
- people difficult to wake
- reduction in brains electrical activity
- delta brain waves (slow, large, regular) - lower in frequency and higher in amplitude
- delta waves signify Slow Wave Sleep (SWS)
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Physical side of Stage 4 (4)
- physiological signs similar to stage 3
- muscles are completely relaxed
- person very difficult to wake
- Sleepwalking, talking, night terrors and bedwetting happen in these stages
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Physical side of REM sleep (6)
- Beta brain waves - irregular, low amplitude and high frequency
- body's internal functioning is more active
- HR = regular and faster
- breathing = quicker
- blood pressure rises
- muscles limp - occasional twitches
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