Sleep Flashcards
(28 cards)
Circadian Rhythm
cyclical bodily rhythms Hormone (melatonin) body temperature alertness (Supercharasmatic Nucleus (SCN)
Circadian Rhythm
generated by endogenous clock
A free-running animal is maintaining its own cycle
The cue to synchronize with the environment is called a zeitgeber—German for “time-giver.”
Jet Lag
disruption of the circadian rhythms mismatch of the internal circadian clock and external time Traveling west = “phase-delays” Traveling east = “phase-advances”
Shift Work
Sleep duration depends on when one goes to sleep Working at night does not reliably change the circadian rhythm People can adjust to night work
recent report on sleepwork
Recent Report 22 people shift to night worker Genetic fine-tuning is lost at night Rhythmic genes become out of sync
Supercharasmatic Nucleus
Control center of the circadian rhythms of sleep and temperature Located above the optic chiasm part of the hypothalamus
The Retinohypothalamic
Pathway in Mammals
Retina, optic chiasm, SCN, lateral geniculate nucleus
Two types of genes are responsible for generating the
circadian rhythm
Period: proteins called PER Timeless: proteins called TIM In mammals, retinal ganglion cells detect light and release glutamate in the SCN. Glutamate promotes production of the Per protein
Melatonin
Pineal Gland Produces Melatonin Release changes the circadian and circannual rhythm Sea creatures use melatonin, too
Sleep
state that the brain actively produces Characterized by a moderate decrease in brain activity and decreased response to stimuli
EEG
Electroencephalography (EEG) records electrical activityin the brain.
Electro-oculography (EOG) records eye movements.
Electromyography (EMG) records muscle activity.
Sleep stages
Stage 1 Sleep brief stage; sensation of falling Stage 2 Sleep 20 minutes; spindles (bursts of brain activity) Stage 3 Sleep brief; transitioning to deeper sleep Stage 4 Sleep 30 min.; delta (large, slow) brain waves; deep sleep REM Sleep 10 minutes; vivid dreams
NREM (non-REM) sleep
includes Stages 1 through 4 involves lower-frequency brain waves, decreased pulse and breathing,and occasional, simple dreams serves a biological need (NREM needs met before REM needs)
REM
recurring becomes longer as night goes on vivid dreams Role in learning and memory paradoxical sleep externally calm (muscles) internally aroused (heart rate)
During REM sleep
Activity increases in the pons and the limbic system
Activity decreases in the primary visual cortex, the
motor cortex, and the dorsolateral prefrontal cortex
PGO waves
Regulated by 5-Ht and ACh
Sleep is mediated by
A forebrain system - SWS
- A brainstem - wakefulness
- A pontine - REM
- A hypothalamic system
Neurochemical
Basal Forebrain GABA ACh Pontomesencephalon ACh and glutamate Locus Coeruleus Norepinephrine Hypothalamus Histamine Basal Forebrain SWS Reticular formation Wakefulness Pons Cortical arousal Inhibits movement in REM Locus Coeruleus Usually dormant during sleep Hypothalamus Promotes wakefulness Immunology
Why we need sleep
Evolutionary Function safety energy conservation/ efficiency Restorative Function body rejuvenation Restore and repair brain tissue Brain Plasticity enhances synaptic connections Increases neuronal growth memory consolidation
effects of sleep loss
fatigue impaired concentration immune suppression irritability slowed performance increased accidents
Natural remedies for insomnia
Exercise Avoid caffeine (including chocolate) Dimmer lights Avoid naps Wake at same time each day Turn clock away
Narcolepsy
uncontrollable sleep attacks
may lapse directly into REM sleep, often
at inopportune times
Ritalin – increase DA and NE
Hypocretin
Prevents transition from
wakefulness to REM
sleep
Lose of Hypocretin Neurons
Hyper somnia
12-14 hours per day plus nap
Fatigue, stressed –out feeling
Rule out medical
Sleep apnea
intermittently stop breathing during sleep
frequent momentary awakenings
usually unaware of these episodes
