We sleep for nearly 13 of our lives Concentration Memory and Coordination Sleep Loss Alcohol Lack of sleep can increase risk of diabetes cardiovascular disease and heart attacks stroke depression high blood pressure obesity and infections ID: 774891
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Slide1
Sleep
Swetha Rao
Slide2Why is sleep important?
We sleep for nearly 1/3 of our livesConcentration, Memory, and CoordinationSleep Loss = AlcoholLack of sleep can increase risk of diabetes, cardiovascular disease and heart attacks, stroke, depression, high blood pressure, obesity, and infectionsSleep Disorders affect up to 70 million people
Slide3Slow Wave Sleep
First hour or so brain waves slow down
relaxation of the muscles and the eyes
Heart rate, blood pressure, and body temperature all fall
If awakened, most people recall only fragmented thoughts, not an active dream
Slide4REM Sleep
Rapid Eye MovementNext half hour or so, neocortical EEG waves become similar to wakingAtonia: paralysis of the body’s muscles (only the muscles that allow breathing and control eye movements remain active) Active dreamingHeart rate, blood pressure, and body temperature become much more variableMen often have erections First REM period usually lasts 10 to 15 minutes.
Slide5Stages of Sleep
Slide6Insomnia
Initially or partway awakeningShort-acting sedatives and sedating antidepressant drugs suppress deeper stages of slow wave sleep
Slide7Obstructive Sleep Apnea
Deeper sleep = Airway muscles collapse and close airway
Can’t enter deeper stages of slow wave sleep
High blood pressure, increased risk of heart attack, increased risk of automobile accidents,
Treatments to reduce airway collapse: lose weight, avoid alcohol and sedating drugs, avoid sleeping on back
Devices that induce continuous positive airway pressure
Slide8Muscles fail to become paralyzed
Periodic Limb Movements
Intermittent jerks of legs and arms as entering slow wave sleep
REM Behavioral Disorder
Muscles fail to become paralyzed
Act out dreams
Common in Parkinson’s patients
Treated with: benzodiazepine (
clonazepam
)
Slide9Narcolepsy
Switching mechanisms don’t work properly
Loss of nerve cells in the lateral hypothalamus which contains the neurotransmitter
orexin
Narcoleptic Dog:
http://www.youtube.com/watch?v=X0h2nleWTwI
Slide10Sudden Sleep Attacks during the day
Hypnagogic
Hallucination:
Enter REM sleep and dreaming state while still partially awake
Cataplexy
: Attacks of paralysis triggered by emotional experience
Slide11Sleep Regulation: AWAKE
Acetylcholine and Monoamines (norepinephrine, serotonin, dopamine, and histamine)
Slide12REM sleep:Cholinergic nerve cells send signals to activate the thalamusEEG similar to wakefulnessMonoamine pathway is quietPerceived as a dream
Slide13Waking Up
Two groups of nerve cells in hypothalamus
Ventrolateral
preoptic
nucleus:
GABA and
galanin
When they fire, they turn off arousal system and cause sleep
Damage = irreversible insomnia
Neurotransmitter
orexin
:
Excitatory signal to monoamine neurons
Orexin
levels in patients with narcolepsy are abnormally low
Slide14Need for Sleep: Homeostasis
Body’s need to seek a natural equilibriumAdenosine (chemical) increases in the brain during prolonged wakefulness levels modulate homeostasisCaffeine acts as an adenosine blocker
Slide15Circadian Timing System
Suprachiasmatic nucleus: group of nerve cells in hypothalamus that acts as a master clockCells express clock proteins which go through biochemical cycle of 24 hrsReceives input from retina so can be reset by light
Slide16Suprachiasmatic
nucleus
Subparaventricular
nucleus
Dorsomedial
nucleus of
hypothalamas
Ventrolateral
proptic
nucleus (
orexin
)
Regulate sleep and arousal