chapter 9 Flashcards
sleep
a regularly occurring ASC and is characterised by a loss of conscious awareness
sleep disorder
is a disruption to the normal Non Rapid Eye Movement (NREM) – Rapid Eye Movement (REM) sleep cycle
eg. insomnia, sleep apnea, narcolepsy
sleep is considered ASC because…
– A distorted sense of time,
– less self control,
– perceptual and cognitive distortions,
– fewer content limitations,
biological rhythms
cyclic changes in bodily functions or activities that repeat themselves through time in the same order
eg.
body temp, blood pressure,
two categories of biological rhythms
circadian and ultradian rhythms.
circadian rhythm
involves changes in bodily functions or activities that occur as part of a cycle with a duration of about 24 hours.
suprachiasmatic nucleus
an internal biological body clock that regulates activity of the sleep–wake cycle
It is located in the hypothalamus in the brain.
governs release of melatonin from the pineal gland
melatonin
a sleep hormone, causes sleepiness and is released when it is dark.
adrenalines influence
nfluencing such properties as blood pressure and heart rate.
sleep wake cycle
slightly longer than 24 hours
endogenous - based on internal biological factors.
zeitgeners
“light” appears to readjust this small mismatch between day and night and our natural sleep–wake cycle.
ultradian rhythm
a biological rhythm that is shorter than 24 hours.
eg. NREM/REM cycle
NREM Sleep
(non -rapid eye movement sleep)
REM sleep
(rapid-eye movement)
REM ans NREM similarities
These occur in continuous cycles, with one following the other
NREM
consists of 4 distinct stages,
each of which can be identified by a different brain wave pattern.
80% of our sleep time is spent is NREM sleep.
first half of sleep more than second
NREM 1
in the NREM sleep cycle occurs as we drift into and out of a true sleep state.
hyping jerk
• decrease in heart rate, respiration, body temp, muscle tension
alpha waves are replaced by theta waves which have a
mixture of high and low amplitude.
5-10 mins
NREM 2
is a light stage of sleep (truely asleep)
lasts 10-20mins
sleep spindles
• -body movements lessen
• -breathing becomes more regular
Brain waves are mainly theta waves, but are slightly lower in frequency and higher in amplitude than the theta waves in stage 1
NREM 3
is the start of the deepest stage of sleep
AKA moderately Depp sleep
10 mins
heart rate, blood pressure & body temp continue to drop
Delta waves make up about 20-50% of the brain waves recorded during stage 3, being slow, large, regular brain waves
Delta waves are lower in frequency & higher in amplitude
in Slow wave sleep for 30 mins
NREM 4
is the deepest stage of sleep.
muscles completely relax and we barely move
Delta waves dominate & are even slower and larger than in stage 3
In the first cycle of sleep, a person may spend up to 20 min in stage 4.
• However, as the night progresses, less and less time is spent in stages 3&4.
REM sleep
is a period of rapid-eye movement sleep during which the eyeballs rapidly move beneath the closed eyelids, REM sleep is beta waves like those produced during alert wakefulness
heart rate is faster & more irregular, blood pressure rises.
most dreaming occurs.
paradoxical sleep
internally the brain and body are active, while, externally, the body appears calm and inactive.
restoration theory
proposes that sleep provides ‘time out’ to help us recover from depleting activities during waking time that use up the body’s physical and mental resources
purpose of sleep
sleep provides an opportunity for the body to replenish the stores of energy used throughout the day
It also allows any damaged cells to be repaired and various muscles to be detoxified or to rid themselves of waste products
sleep is a period of physiological rest.
restorative theories NREM
sleep is thought to be important for restoring & repairing the body and REM sleep is thought to restore the brain and may have a role in higher mental functions such as learning and memory. body
restorative theories REM
REM sleep has a restorative role throughout the lifespan by exercising groups of neurons in the brain that form circuits. REM sleep may assist in consolidating the memory of newly learned info. mind
REM rebound
involves catching up on REM sleep immediately following a period of lost REM sleep by spending more time than usual in REM sleep when next asleep.
evolutionary (circadian therapy
proposes that sleep evolved to enhance survival by protecting an organism through making it inactive during the part of the day when it is most risky or dangerous to move about
restorative theory supportive theory
– Marathon runners spend more time in NREM sleep
sleep activates growth and increases immunity
– Cognitive decline occurs with sleep deprivation
restorative theory limitations
– people who are bed-ridden still experience the same proportions of NREM sleep, the brain is active when replenishing
evolutionary supportive evidence
- there is a sequential pattern that demonstrates that the energy requirements of animals and number of predators correlates with sleep requirements
– sleep conserves energy, so hibernation is important when food is scarce in the Winter months.
evolutionary limitations
While sleeping animals are vulnerable to predators, it doesn’t explain why we must have so much sleep.
newborns and infants
sleep for 16 hours a day, and include 8 hours of REM sleep per night on average. By 3 months, sleep cycles become more regular. By 12 months, the infant sleeps 14-15 hrs per day.
young children
total sleep time continues to decrease (13 to 11 hrs b/w 2-5yrs). Time spent in REM sleep continues to decrease and NREM increases.
teenagers
spend 8-9 hours asleep per night and experience 2-2 1⁄2 hours of REM sleep per night on average. Experience a sleep-wake cycle shift (ch 10) with the want to go to sleep later and wake later. Irregular sleep patterns are commonly experienced.
adults
sleep for about 8 hours, and experience 2 hours of REM sleep per night on average.
elderly
spend about 6-7 hours of sleep, with no stage 4 sleep, and experience 2 hours of REM sleep per night on average. Tend to need to sleep earlier in the evening and wake early in the morning.
