Key concepts

• functions of sleep?

  * healthy brain - synapses get larger and important to get rid of toxins

  * physical repair - damaged cells repaired and hormones are rebalanced and immune system is more active

  * emotional stability
• each CYCLE of sleep lasts for about?

  90 minutes
• stages of sleep?

  * stage 1 - drowsy sleep; brainwaves and muscle activity slow down; eyes move slowly

  * stage 2 - loss of conscious awareness; slow brains waves with occasional bursts of activity; no eye movement

  * stage 3 - very slow brain waves alternate with shorter, faster brain waves; no eye or muscle movement

  * stage 4 - very slow brain waves; no eye or muscle movement; very difficult to wake people

  * REM sleep - most dreaming happens; rapid eye but no muscle movement; brain waves fast like when awake
• pineal gland and melatonin?

  * pineal gland is an endocrine gland in centre of brain producing hormone called melatonin

  * melatonin sends us to sleep

  * pineal gland isn't active during day but 'turned on' as night falls

  * this is when melatonin is released to blood stream

  * levels of melatonin remain high for 12 hours after first being released
• sleep onset insomnia causes?

  * anxiety problems

  * too much caffeine or nicotine

  * heavy meal before bed

  * looking at screens before bed
• sleep maintenance insomnia causes?

  * feelings of depression

  * too much alcohol

  * being with someone who snores
• endogenous pacemakers?

  internal clock that regulates our body's our sleep and wake cycle

  * called SCN (suprachiasmatic nucleus)

  * sends messages to parts of body controlling body temperature and hormone production
• exogenous zeitgeber?

  cues external to body to help regulate sleep and waking

  * the sun

  * social factors like eating times