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112 Cards in this Set

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  • Back
What causes REM sleep debt?
sleep deprivation
what happens if you are in REM sleep debt and you go to sleep?
you'll have more REM sleep
What is REM?
rapid eye movement
What is unihemispheric sleep?
Sleeping but on only one half of the brain.
Function of unihemispheric sleep:
Protection - to remain alert against predators, or stay swimming if you're a fish.
What is the normal length of the REM cycle in humans?
In birds?
Humans - 90-110 min

Birds - 2.5 min
How many people in the US suffer moderate to severe sleepiness?
63 million - 1/5 of americans
What percent report interference w/ daily activities?
What percent report nodding off while driving?
What is the normal sleep requirement for:
Adults = 8.5 hrs
Infants = 14-16 hrs
Children = 10 hrs
Teens = 10 hrs
What is the average amt sleep that adults in US get?
6.8 hrs
2 Functions of sleep:
What 4 things are decreased by inadequete sleep?
1. Alertness
2. physical performance
3. Neuropsycho performance
4. Overall health
Specific functions of NREM sleep: (3)
-Growth/tissue repair
-Immune system enhancement
-Restoration of cerebral energy stores
Specific functions of REM sleep (4):
1. Processing of information
2. Unlearning irrelevent info
3. Memory consolidation
4. Facilitation of learning and memory
Normal healthy young adult:
-Sleep times
-Total sleep time (TST)
-Sleep efficiency
-WASO (wake after sleep onset)
Times: 11pm - 7am
TST = 7-8 hrs
Sleep effic = >95%
WASO = <5%
What is pathological sleepiness?
Falling asleep in less than 5 minutes after you go to bed
What is significant sleepiness?
Falling asleep in 6-15 min after going to bed
How long should it take to fall asleep when you go to bed?
15 min
Stages of Sleep:
Stages of NREM sleep; what percentage is each?
1 - 2-8%
2 - 45-55%
3/4 - 13-23%
What do we call the mixed Stage of 3/4?
-Delta stage
-SWS - slow wave sleep
When does NREM predominate?
During the first half of the night
When does REM predominate?
During the last half of the night
What are the 2 types of REM sleep?
-phasic - rapid eye movement
-Tonic - no eye movement
What is the ratio of time spent in REM vs NREM sleep at night?
How much total time is spent in REM sleep?
90-110 min
How many REM cycles per nite?
What type of sleep do you wake up out of normally?
When do you dream?
What is the deep restful type of sleep?
What type of sleep do children have lots of? How many REM cycles typically?
Stage 4
-typ 4 cycles of REM
How do elderly sleep patterns differ from young adults and children?
Most time is spent in stage 2; little to no time in stage 3/4
-Wakenings much more freq
How is the normal sleep:wake cycle different from the normal day?
It is a little longer; so we're always fighting against the calender...?
4 Regulators of the human sleep-wake behavior:
-Circadian rythms
-Homeostatic processes
-Ultradian regulation
-Environmental cues
Ultradian means:
less than 24 hrs
How does the 2process model describe sleep regulation?
Process S = homeostatic process
Process C = circadian component
How does the homeostatic process regulate sleep?
The longer the organism is awake, the greater propensity they have to sleep.
How does the circadian component regulate sleep?
By its oscillations that affect the propensity for sleep/wake
What is the theory represented by the Reciprocal Interation model?
The ultradian cycle of NREM and REM sleep is due to reciprocal interactions of REM facilitory and inhibitory neurons
4 important locations in the brain for regulating NREM sleep:
What does VLPO do?
-VLPO (thalamus) - TELLS YOU TO GO TO SLEEP - NREM; releases ACh which turns off all REM signals.
-Locus ceruleus (breathing)
-Suprach. nucleus
Where are REM ON CELLS located?
Pedunculopontine nucleus
Where are REM OFF CELLS located?
What protein factor promotes both wake and sleep?
What is an important sleep promoting factor? What inhibits it, how?
-Caffeine inhibits it by competing for its receptors.
What happens to heartrate during sleep?
In what phases of sleep does HR decrease?
Both NREM and REM
What happens to reduce HR in NREM sleep?
Tonic increase in PNS causes bradycardia
What happens to reduce HR in REM sleep?
STill the tonic increase in PNS
Also decrease in SNS
How much does HR tend to decrease during sleep?
10-15 bpm
In which sleep phase does HR vary more?
What do we call the cardiac oscillations during REM?
Tachybrady phenomona
What happens to cardiac output during sleep?
Falls progressively - most during the last sleep cycle, especially during REM.
What accompanies the falling CO during the last sleep cycle?
Oxygen saturation - reaches its lowest low.
consequence of lower CO / O2 sat in cardiopulm patients:
most likely to die during early morning hours.
How does Bloodflow change during NREM sleep?
-Skin, muscle, splanchnic bloodflow changes little
-Cerebral flow decr by 5-25%
How does Bloodflow change during REM sleep?
-Splanchnic/Renal bloodflow increases (rest/repose)DILATE
-Muscle/Skin bflow decreases via Vasoconstriction
What happens to cerebral bloodflow during REM sleep?
Increases by up to 40% of the normal waking levels
What does Bloodflow show about NREM vs. REM sleep?
NREM shows resting brain activity, reduced ativity; where REM shows active brain, increased activity.
How does systemic blood pressure change during sleep?
NREM - falls 5-15%
REM - fluctuates
How does Pulmonary bp change during sleep?
It increases form 18/8 to 23/12
When during sleep is
-PNS predominant?
-SNS changed?
-PNS predomint in both NREM/REM
-SNS is inhibited during REM
Why do BP and HR fluctuate during REM?
Because of phasic vagal inhibition and sympathetic activation
What happens to TPR during NREM vs REM?
NREM: decreases slightly
REM: decreases more
What controls respiration during wakefullness?
a)metabolic/ANS system
b)behavioral/voluntary system
What controls respiration during NREM sleep?
Metabolic ANS system (blood gas levels)
What controls respiration during REM sleep?
Behavioral - not blood gases; become less sensitive to them.
How do respirations change during NREM sleep?
Minute ventilations become decreased due to a decrease in tidal volume.
What is the respiratory pattern like in NREM sleep?
Stable and rythmic.
How do respirations change during REM sleep?
Same as in NREM; become decreased.
What is the respiratory pattern like in REM sleep?
Unstable and irregular - especially in the phasic component.
How do bloodgas levels change during sleep?
-CO2 -O2 (arterial)
-O2sat -Alveolar O2
CO2 increases 2-7 mmHg
All O2 levels decrease
What is a normal partial press of CO2 and what would it be during sleep?
Norm: 40
Sleep: 42-47
What is a normal partial press of arterial O2 and what would it be during sleep?
Norm: 90
Sleep: 80-87
How much do O2 sat levels drop during sleep?
1-2%; a drop in 4% would be pathological!
What does hypercapnia do normally, when not sleeping?
Stimulates an arousal
What happens to the hypercapnic arousal stimulus during sleep?
It becomes stronger than the hypoxemia arousal stimulus.
How much does CO2 have to increase to stimulate an arousal?
8-15 mm Hg.
How much does O2 sat have to decrease to stimulate an arousal?
How many times do CO2 levels increase enough to cause an arousal during the normal sleeping?
<5X per hour
What do we call the pattern of increasing CO2 levels until they stimulate an arousal?
Cheyne-Stokes breathing
Summary; how is the hypoxic ventilatory response changed in NREM sleep? in REM?
NREM: decreased
REM: further decreased
2 factors that contribute to the decreased hypoxic ventilatory response during sleep:
-Increased upper airway resistance
-Decreased chemosensitivity
What happens to the Hypercapnic Ventilatory response in NREM and REM sleep?
NREM: decreased
REM: further decreased
2 factors that contribute to the decreased hypercapnic ventilatory response during sleep:
-Increase in upper airway resistance
-Decreased # of functional medullary respiratory neurons
Why do CO2 AND O2 ventilations decrease during sleep?
-Metabolism slows at sleep onset
-Ventilation is proportional to metabolism
When does metabolism speed back up?
at 5am
Why is the Partial press of CO2 increased during sleep?
Because of the alveolar hypoventilation caused by decreased minute ventilations (decreased tidal volume).
How do the pupils change during
-NREM and REM sleep
-REM sleep
NREM/REM: PNS increases to cause constriction
PHASIC REM: central inhibition of PNS outflow causes dilation
What happens to body temp at onset of sleep?
It falls 1-2 degrees C
When is the lowest body temp seen?
in 3rd nrem/rem cycle
What happens to thermoregulation during REM sleep?
It is inoperative
So what is the difference of body regulation between NREM and REM sleep?
NREM: see sweating/panting (shivering)
REM: no sweat/panting
What happens to the limb muscles during sleep?
NREM: slightly decreased tone
REM: mrkldy relaxed - atonia
What changes in the upper airway muscles occur during sleep?
Upper airway: resistance increases
Lower airway: dilator muscles reduce to reduce resistance.
What happens to Gastric Acid secretions during sleep?
They peak between 10pm and 2am
What happens to gastric motility during sleep?
Mostly inhibition of motor functions.
What 2 changes in esophageal function take place during sleep?
-Swallowing suppressed
-Saliva output decreased
How is intestinal motility affected by sleep?
-Migrating motor complex recurs every 90 min in stomach and small intestine, but at its lowest velocity relative to other times of the day.
What does the periodicity of the MMC correlate with?
The NREM/REM cycle
What important hormones are released during sleep?
Growth hormone
Gonadotropic hormone
When do plasma concentrations of GH peak? How long does it stay?
-90 min after sleep onset
-circulates 1-3 hrs during SWS
What does ACTH induce?
Cortisol release
When does Cortesol peak and at its lowest?
Lowest: in early part of sleep
Peak: between 4-8 AM
When is prolactin highest and when does it begin to rise?
Begins to incr 60-90 min after sleep onset
-Highest during sleep from 5AM-7
When do Gonadotropic hormones increase?
During prepuberty and puberty - during sleep
3 hormones with no relationship to sleep:
What is the relationship of TSH with sleep?
Highest just before bedtime, lowest during day
When does aldosterone peak?
Just before bedtime
When does melatonin begin to rise and peak?
-Begins to rise in evening
-Peaks betwen 3-5AM.
What suppresses melatonin levels?
Bright light
What might be the function of sleep?
Energy conseration