The sleep cycle Flashcards
Define sleep stages
- Distinct periods of sleep which make up a cycle
How many stages do we usually go through?
- 5 stages
1, 2 , 3, 4 and rapid eye movement (REM) sleep
A complete sleep cycle takes an average of
90 minutes
Stage 1 of sleep cycle
involves light , drowsy sleep , people drift in and out of sleep and can be stirred quite easily, the eye moves slowly and the muscle activity slows down.
Many people experience a sudden muscle spasm followed by sensation of falling, brainwaves are more synchronised and slower than when we are awake = alpha waves which slow down and are called = theta waves. If a persons woken up during this period = feel they have not slept at all
Stage 2 of sleep cycle
eye movements stop and theta waves become slower with occasional bursts of rapid brain movement. We lose conscious awareness of the outside world at this point
Stage 3 of sleep cycle
- extremely slow brain waves = delta waves
Stage 3 - 4 of sleep cycle
- stages of deep sleep = difficult to wake someone. In deep sleep , there is no eye movement or muscle activity and more growth hormones are released into the body = helps with physical repair
REM stage (5)
- breathing is quicker and less regular .
Our eye moves rapidly and our limb muscles are temporarily paralysed . Brain waves similar to an awake person and so are fast. Heart rate increases, blood pressure rises , body temp can go up or down= time when most dreams occur.
Woken up during this period = normally remember sleep
How many interval of REM sleep do most people experience.
3-5
The first sleep cycles each night have relatively —– REM sleep and long periods of deep sleep, but, later in night , —— periods get longer
shorter, REM
APX how long do adults spend in stage — in sleep cycle and — and — —.
2, REM, other 3
50%, 20%, 30% divided
