08 - Sleep and Dreams Flashcards
What are Circadian rhythms
the biological clock that synchronizes with the 24 hour cycle of day and night
How does the Circadian rhythm work?
Activating light-sensitive retinal proteins, which then trigger signals in the brain’s suprachiasmatic nucleus (SCN). The SCN causes the brain’s pineal gland to decrease its production of the sleep-inducing hormone Melatonin in the morning or increase it in the evening.
How long are the 5 cycles of our sleep stages?
90 min (total)
What is REM sleep?
Rapid Eye Movement sleep, A recurring sleep stage during which vivid dreams commonly occur. Also known as “paradoxical sleep”, because the muscles are relaxed but other body systems are active.
What are alpha waves?
The relatively slow brain waves of a relaxed, awake state.
Why do we yawn?
In response to reduced brain metabolism.
How can we record Alpha waves?
using an EEG
What are sleep spindle?
A burst of rapid, rhythmic brain activity in an EEG reading. Occurs in stage 2 sleep
What is sleep?
Periodic, natural, reversible loss of consciousness - As distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation.
Define hallucinations
False sensory experiences, such as seeing something in the absence of an external visual stimulus.
What are delta waves?
The large, slow brain waves associated with deep sleep
Describe stage 1 of sleep
May experience fantastic images (like hallucinations, falling, etc)
Describe stage 2 sleep
Relax more deeply, lasts about 20 min.
Characterized by periodic appearance of sleep spindles.
Still easily awakened.
Sleep talking can occur in this stage, but is not limited to this stage.
Describe stage 3&4 sleep
Transitional stage 3 into deep sleep in stage 4.
Starts large slow Delta waves in 3.
Both last for about 30 minutes
Hard to a weekend.
And of stage 4: Children wet the bed or sleepwalk.
Describe REM sleep
Ochers about an hour after you fall asleep.
Ascend from your initial sleep dive, Up through stages 3,2, Brain waves become rapid (As if in stage 1) - Heart rate rises, breathing becomes rapid regular.
Eyes darting (Announcing the beginning of a dream)
Genitals usually become aroused.
In what two stages do we spend half our night in?
3 and 2
Describe brain/neural activity during REM sleep
Although brains motor cortex is active during REM sleep, brainstem blocks it’s messages; Leaving muscles relaxed - Essentially paralyzed.
What happens in our sleep cycles as the night wears on?
Stage 4 sleep gets progressively briefer and then disappears.
The ram and stage to sleep. Get longer.
What percentage of our nights sleep is in REM?
20 to 25%
What is sleep debt?
Accounts of the loss of sleep but our brain maintains
What are some benefits of sleep?
Neurogenesis, Increases concentration, boosts mood, moderates appetite, fortifies immune system.
What are effects of sleep deprevation?
Overall unhappiness, Concentration and memory impairment, Increases the hunger arousing hormone ghrelin, Decreases hunger suppressant leptin, Increases stress hormone cortisol, Suppresses immune system
What are 5 theories of sleeps function?
- Sleep protects (sleep patterns have kept us safe and inside at night - away from predators)
- Recuperate (Restore and repair brain tissue
- Making memories (restoring and rebuilding)
- Feeds creative thinking
- Growth (During sleep pituitary gland releases Hormone - lessening as we age)
What are free radicals?
Molecules that are toxic to Neurons
