Sleep Stages 5.0 / 5 based on 1 rating ? PsychologySleepA2/A-levelAQA Created by: Ella GreenCreated on: 02-06-14 13:24 Stages of Sleep Daily cycles of wakefulness and sleep follow a circadian rhythm Within the sleep portion = ultradian rhythm First four stages = NREM sleep Fifth stage = REM sleep Accompanying movements of the eye beneath of closed lids One sleep cycle goes through all five stages and lasts about 90 minutes 1 of 3 Stages 1 and 2 Light sleep Change in the electrical activity of the brain Awake brain = beta waves More relaxed = alpha waves Brain waves become slower and more regular, and have a greater amplitude Going to sleep = theta waves Accompanied by bursts of activity Incrased wave frequency = sleep spindles Increase wave amplitude = K complexes 2 of 3 Stages 3, 4 and 5 Stages 3 and 4 Characterised by even slower delta waves Slow Wave Sleep (SWS) Very hard to wake someone up Person is not unconscious and will be aroused by, for example, a baby crying 'Repair work' is undertakn Important biochemical processes take place such as production of growth hormones Stage 5: REM sleep Fast, desynchronised EEG activity resembling the awake brain These cycles continue hroughout the night SWS period gets shorter REM gets slightly longer as the night continues Each sleep cycle = 90 minutes 3 of 3
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