Question

1. define circadian rhythm. give an example.
2. how many stages of sleep are there?
3. on average, how long does it take to go through one full cycle of sleep?
4. understand the sleep - cycle chart

stages of a normal sleep cycle
awake
rem sleep
nrem stage 1
nrem stage 2
nrem stage 3
1 2 3 4 5 6 7 8
hours of sleep
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Explanation:

1. A circadian rhythm is a roughly 24 - hour cycle in the physiological processes of living beings. An example is the sleep - wake cycle in humans, where we are typically awake during the day and sleep at night.
2. There are 5 stages of sleep: nREM Stage 1, nREM Stage 2, nREM Stage 3, REM sleep, and the awake state which is part of the cycle when transitioning in and out of sleep.
3. On average, it takes about 90 - 110 minutes to go through one full cycle of sleep.
4. The sleep cycle chart shows the different stages of sleep (nREM Stages 1 - 3, REM sleep) occurring in cycles over the course of several hours of sleep. Each cycle has a pattern of transitioning from lighter sleep (nREM 1 - 2) to deeper sleep (nREM 3) and then to REM sleep.

Answer:

1. A circadian rhythm is a roughly 24 - hour cycle in the physiological processes of living beings. Example: human sleep - wake cycle.
2. 5 stages.
3. 90 - 110 minutes.
4. The chart shows the pattern of nREM Stages 1 - 3, REM sleep occurring in cycles over hours of sleep with transitions between lighter, deeper sleep and REM.