topic 11 - sleep physiology Flashcards
what is sleep
naturally recurring and reversible biobehavioral state characterised by relative immobility, perceptual disengagement, and subdued consciousness
what is sleep need
biological requirement for sleep / minimal amount of rest the body requires to prepare for the next day
- defined by individual genetics, and physiology
- does not change after losing a night of sleep or oversleeping
motivates the creation of sleep opportunity
what is sleep ability
amount of sleep an individual can achieve
- approx by total calculated sleep time
- can change from one night to the next depending on life circumstances
what is sleep opportunity
amount of time the person makes available for sleep
- time spent in bed
- under conscious control
- can be greatly affected by environmental factors
provides a context for sleep ability to produce sleep and reinforces the methods used to create sleep opportunity in the first place
what is stage I non REM sleep
more theta activity, loss of alpha, and vertex sharp waves
what is stage II non REM sleep
theta and delta waves, vertex sharp waves, K complexes (vertex sharp wave with a superimposed slow and fast component), and sleep spindles
what is stage III non REM sleep
higher voltage delta waves that are 20-50% of the background over time
what is stage IV non REM sleep
more than 50% delta slow waves
what is REM sleep
- return of beta activity
- rapid eye mvmt
- loss of muscle tone (except diaphragm)
- dreaming
lasts about 10 min per epoch on average
what is the total REM time over the lifespan
diminishes over time
- 8 hours at birth
- 2 hours at age 20
- 45 min at 70
what happens during REM sleep
memory consolidation and storing previous day to prepare for the next
less time spent here = more of a fog
how does sleep load change throughout the day
low in morning (was just sleeping)
building throughout the day (unloads through sleep)
what are sleep promoting hormones
GABA
melatonin
adenosine
what is the natural circadian rhythm
24.2-25 hours
natural cycle = a bit longer than 1 day