Chapter 11: Sleep Flashcards
exam 3 material
what is circadian rhythm?
Circadian timing refers to the daily fluctuations that
occur in hormone levels, body temperature, sleep-
wake cycle
how does the bodies internal clock work?
superchiasmatic nucleus (SCN)/retino-hypothalamic pathway, decrease in light -> less SCN activity -> less input from sympathetic neurons -> melatonin release from the pineal gland
SCN also manages body temperature, hormone secretion, production of urine, and blood pressure changes
what proteins influence the bodies internal clock?
per, tim, and clock proteins are light-sensitive genes that work in a three way system to either inhibit or increase each other, causes body to release either melatonin or cortisol
what does EEG look like during waking?
alternates between beta (desynchronus) wave and alpha (synchronus) wave patterns of brain activity, sleep spindles are believed to be integral to synaptic plasticity and memory consolidation, K-complexes have been shown to function in sleep and memory consolidation
what kind of waves are associated with each of the 5 stages of sleep as well as being awake?
awake: alpha and beta rhythms
REM: beta rhythms
stage 1 NREM: theta rhythms
stage 2 NREM: sleep spindles and K-complex
stage 3 NREM: delta rhythms
stage 4 NREM: delta rhythms
what are the brain pathways that control waking?
activity of the reticular formation of the medulla
and locus coeruleus keep us awake (ACh and NE)
serotonergic nuclei from the raphe communicate with the POA and SCN and the cortex
raphe nuclei are active during wakefulness, less active during NREM, and silent during REM
what kind of brain activity is associated with NREM?
POA stimulation -> NREM
the POA forms an inhibitory feedback loop with the raphe to promote NREM sleep, activity in the locus coeruleus and the raphe nuclei gradually declines
what kind of brain activity is associated with REM?
locus coeruleus and raphe nuclei become silent
REM-ON areas located in pons, reactivation of locus coeruleus and raphe nuclei leads to either wakefulness or another segment of NREM sleep
what happens during REM sleep?
characterized by dreaming, irregular muscle movements, and rapid movements of the eyes, loss of motor tone, increased brain O2 use, increased and variable pulse and blood
pressure (REM-ON and REM-OFF neurons in pons and
brainstem)
what role do orexins play in sleep?
orexins promote wakefulness, produced in the LH, suppress NREM and REM sleep, appear to help you stay awake
what are the two different chronotypes?
chronotype is the natural inclination of your body to sleep
early birds: more persistent, more resistant to fatigue, lower levels of anxiety and depression
night owls: less physical activity, risk takers, more creative
why do we sleep?
benefits of sleep include healthy immune system
function, improved cognitive abilities, better memory
NREM and REM sleep seems to be a time of enhanced synaptic plasticity and memory consolidation, REM sleep probably plays a role in brain development, when deprived of REM sleep, humans show REM rebound – more REM than usual in subsequent days
what causes seasonal affective disorder (SAD)?
the precursor to melatonin is serotonin, serotonin is activated by light
winter -> disruptions of melatonin release by uneven patterns of daily light
what are the two types of insomnia?
most common sleep-wake disorder, onset insomia is trouble falling asleep and maintenance insomia is trouble staying asleep
what is narcolepsy?
extreme levels of daytime sleepiness
cataplexy: the muscle paralysis that is normally associated with REM sleep occurs when the person is completely awake
orexins (hypocretin) underactive in narcolepsy
