Sleep Flashcards
Def: Sleep Debt
the cumulative loss of sleep and the consequent pressure for sleep that results from an inadequate amount of physiological normal sleep
-increased sleep debt causes an increase in sleep pressure
What happens to sleep debt is a night of sleep is skipped
sleep debt will continue to accumulate until it is paid off
Approximately how many hours without sleep will decrease driving performance the same as 0.5 blood alcohol level
more than 16 hours
what percentage of drivers in Canada have admitted to driving drowsy
60%
-15% have fallen asleep while driving
Airplane shift length affect on accident frequency
-increased accident frequency as shift length increases
-dramatic increase at 13+ hours
Medical resident shift length affect of serious medical errors
-Comparison of traditional 29 hour shifts and two shifts of 14 and 15 hours with a rest period in between
-significantly more errors seen in traditional compared to intervention
Microsleeping
when the brain transitions to deep sleep for mere seconds
-1 to 15 seconds long
-occurs to protect brain
-No memory of few seconds
-forced repayment of sleep debt
How to calculate how sleep deprived you are
amount of sleep we need subtract the amount of sleep we get
How much sleep do children 6-13 years old need
9-11 hours
How much sleep do teens ages 14-17 require
8-10
how much sleep do adults 18-64 require
7-9 hours
how much sleep do seniors ages 65+ require
7-8 hours
Average length of sleep for canadians
6.9 hours
What factors are disparities in sleep often related to
Age
Race
income
BMI
sex
how does income affect sleep
higher income households are seen to get more sleep than lower income households
how is sleep affected by race
white individuals get the highest amount of sleep and black individuals get the least amount of sleep
Sleep latency
the time between when you go to bed and when you fall asleep
Mid-sleep disturbance/ sleep fragmentation
when you wake up in the middle of the night
Sleep efficiency
sleep time divided by time in bed
Sleep Apnea
breathing repeatedly stops and starts
-wake up to catch breath without realizing it
Sleep insomnia
trouble falling asleep and staying asleep
-more prevalent in women, older adults, pregnant women
Effects of sleep loss on academic performance
-study conducted on 414 university students
-used Pittsburg sleep quality index to categorize into low vs high sleep quality
-low group got a B+ average and high group got a B+ average
Health costs of sleep loss
-Obesity
-heart disease
-weakens the immune system
-mental illness
- premature death
Physiological differences between sleeping and being awake
-body temperature regulated at a lower set point
-heart rate and blood pressure decrease
-respiratory rate decreases and becomes more regular
-brain activity changes
What does EEGs measure
Measures the EPSPs and IPSPS in a population of neurons in the cortex of the brain
What does EEG stand for
Electroencephalogram
Steps of neurotransmitters being released
- action potential reaches axon terminal and depolarized membrane
- Voltage-gated Ca2+ channels open and Ca2+ flows in
- Ca2+ influx triggers synaptic vesicles to release neurotransmitter
- Neurotransmitter binds to receptors on target cell
What does an EEG require of the neuros in order for the signal to be detected
HIGH STRENGTH SIGNAL AT SCALP
-population fires simultaneously
-neurons in population must point in same direction
What does EMG stand for
Electromyogram
What does EOG stand for and what does it measure?
Electrooculogram
-movement of eyes
Differences in EEGs while awake compared to asleep
WAKE
-Fast, low amplitude waves that are desynchronized
SLEEP
-slow, high amplitude waves that are synchronized
-optimal for restoring energy
What does AAS stand for
ascending activating system
Location of the AAS
extends the length of the brainstem
What activates the AAS
Visual impulses
auditory impulses
exercise
cold water on skin
How does the AAS work
stimulus activates the AAS in the brainstem and it transmits the signal to the thalamus which in turn relays the signal to the cortex to wake it up
Arousal-promoting areas
LC - locus coeruleus
Raphe - dorsal & median raphe nuclei
TMN - tuberomamillary nucleus
Which neurotransmitter does the LC release
Norpinephrine
Which neurotransmitter does the Raphe release
serotonin
Which neurotransmitter does the TMN release
histamine
What is the sleep-promoting area and what neurotransmitter does it release
VLPO - ventrolateral preoptic area
GABA
What area releases orexin and what is the function
LHA - Lateral hypothalamic area
-back up system to inhibit VLPO
What is the function of arousal-promoting and sleep-promoting regions
-Arousal-promoting areas inhibit the VLPO during arousal
-sleep-promoting areas inhibit connections to arousal promoting nuclei when trying to sleep
Thalamus Burst Mode
Occurs when AAS is off (sleep)
-thalamus produces bursts of APs to synchronize activity in the cortex
Thalamus Spike Mode
Occurs when AAS is on (wake)
-thalamus produces single APs to desynchronize activity in the cortex
What factors cause sleepiness
-biological clock
-homeostatic factor (sleep pressure)
Suprachiasmatic nucleus
SCN
-holds bio sleep clock
-has clock genes
-located in the hypothalamus
Clock genes
-set brain time to 24.2 hours (creates proteins on this timeline
-without time cues we stay up later and later each night
Zeitgebers
Environmental clues about time that reset brain time to 24 hours
-Sunlight (melatonin is released when the sunsets to make us sleepy)
-exercise
What biological process causes sleep pressure
-increase in adenosine concentration will cause increase in sleep pressure when the molecule binds to its receptors
-adenosine is the by-produce to ATP breakdown
-Increases throughout the day until triggering sleep
How does caffeine act to inhibit sleep pressure
acts as antagonist by binding to adenosine receptors and blocking adenosine
Stage 1 of sleep
-drowsy state
-rhythms syncing
Stage 2 of Sleep
-consciousness fades
-brain slows more and continues to sync
-sleep spindles and K complex help brain transition
-thalamus switches from spikes to bursts
-takes 10-25 minutes
Slow Wave sleep/ Deep sleep
- lasts 20 - 40 minutes
-completely unconscious
-CSF cleans brain debris
-pay back most sleep debt
-consists of delta waves
REM Sleep
-paradoxical sleep
-awake desynchronized brain
-paralyzed body
-rapid eye movement
Characteristics of sleep stages cycle
-90 minutes in length
-SWS longer at the beginning and shortens
-REM lengths later in the night
-uses stage 2 as bridge stage between the two
Good nights sleep stage percentage in young adults
REM 25%
SWS 20%
stage 2 50%
stage 1 5%
Percent of SWS in older adults
5%
SWS changes after sleep deprivation
-time spent in SWS increases
-power of the Delta waves increases
Impact of Naps on sleep
-increases sleep latency
-reduces SWS
-Reduces delta wave magnitude
Main evidence that the brain favors SWS
In a regular nights sleep 19% is spent in SWS
A restricted nights sleep spends 44% in SWS
Function of REM sleep
-alters memories so they are less emotionally destressing
Features of REM sleep
-EEG is fast and low amplitude
-vivid and emotional dreams
-body is paralyzed so you don’t act out your dreams
-Things that disrupt REM increase amygdala activity and emotional distress
