Sleep And Dreaming Flashcards
How does sleep keep us safe?
When it’s dark, predators are more likely to hunt for us if they are nocturnal. When we are asleep we are still and so less easy to spot by predators.
How is sleep good for a healthy brain?
The gaps between brain cells get larger when we are asleep allowing us to remove toxins that would otherwise damage our brain.
It also consolidates new memories from that day.
How is sleep important for physical repair?
a ) damaged cells can be repaired
b ) hormones are rebalanced
c ) deep sleep can trigger growth hormones.
d ) immune system activity increases.
How is sleep important for emotional stability?
Once we wake up, we wake up re-energized and alert.
There is also a decrease in the stress hormone called ‘cortisol’ meaning we also feel calm and relaxed.
How much time do we spend sleeping (usually) in one cycle?
90 minutes
How long is stage one of sleep usually?
10% - so 9 minutes
How long is stage two of sleep usually?
50% - so 45 minutes
How long is stage three of sleep usually?
10% - so 9 minutes
How long is stage four of sleep usually?
10% - so 9 minutes
How long is REM sleep?
20% - so 18 minutes
What is the brain activity in stage one of sleep?
alpha waves change to theta waves and brain activity is slower than when awake.
What is the brain activity in stage two of sleep?
Theta waves.
What is the brain activity in stage three of sleep?
Delta waves with shorter faster waves.
What is the brain activity in stage four of sleep?
Delta waves only.
What is the brain activity in stage five (REM) sleep?
Fast waves; faster than when asleep.
