stages of sleep cycle

Question 1

sleep cycle

Answer 1

consistens of a period of NREM sleep with transitions between its 3 stages and a periof of REM
- young adults the cycle is repeated 5-6 times each night
- avergae length of the first NREM-REM slep cycle is about 70-100 mins
- the second adn later sleep cyces are generally around 90-120 minutes

Question 2

REM vs NREM amount percentage

Answer 2

REM - 20-25%
NREM - 75-80%

Question 3

stage 1

Answer 3

• involuntary muscle twitches
• slow, rolling eye movement may be observed
• slowdown in brain wave pattern (theta waves beings to replace alpha waves)
• decrease in heart rate, respiration and body temp
• low arousal threshold (easily woken up by a nudge or noise))
• for 5 mins for adults, can be 1min or up to 7/8 mins

Question 4

stage 2

Answer 4

• less body movements
• eye movements stop
  -brain waves patterns is slower (theta waves)
• body temp, heart rate decreases
• higher arousal than S1 (can be easily woken up with loud stimuli)
• lasts 10-25 mins and lengthens with each cycle

Question 5

stage 3

Answer 5

• muscle is very relaxed
• lack of eye movement
• brain waves slow down more, delta waves become more prominent
• heart rate, body temp and breathing rate slows
• higher arousal threshold (less responsive to external stimuli)
• if waken up they are groggy and disoriented
• last a few minutes or up to 10 mins

Question 6

stage 4

Answer 6

• muscles are completely relaxed and rarely move
• no eye movement
• delta waves dominant the brain waves
• heart rate, body temp are at their lowest and regular
• highest arousal threshold
• spend 20-40 minutes, as night progressives, less time is spent in stage 4 and may even disappear

Question 7

REM

Answer 7

• looks completely relaxed
• spontaneous burst of rapid eye movement
• rapid, irregular mixed frequency activity
• heart rate fastens, and breathing is slow
• highest arousal threshold
• REM sleep increases as the night progresses