PDF - Sleep Flashcards
Progression into REM?
Progression “down” through stages 1, 2, 3, and 4 of NREM, then reverse “up” before first REM occurs
What goes on in Stage 1?
- Drowsiness
2. Early EEG slowing
What goes on in stage 2?
- Asleep but easily aroused
2. Unique sleep spindles on EEG
What goes on in stages 3 and 4?
- Sleep deeps, hard to arouse
2. Slowest (delta wave) EEG activity
Progression of REM sleep?
- First REM period occurs 90 minutes after sleep begins
- Reoccurs every 90 minutes thereafter
- Lasts only a few minutes at first
- Subsequently lengthens in duration to an hour
When is limb hypotonia maximal?
REM sleep
What is seem in REM?
- Limb hypotonia
- Subtle twitches of face and limbs
- irregular pulse and breathing
- Horizontal, rapid, conjugate eye movements
EEG in REM?
Similar to wake state
Recall in REM?
- Recallable dreams occur in REM
- This stage is important for reinforcing memory traces
What does lack of REM cause?
- Anxiety
- Hostility
- Hallucinations
- Amnesia
Impact barbiturates on sleep?
Suppress REM
Sleep changes with age?
- Newborns sleep 15 hours daily
- Frequent yet shorter periods - Elderly Sleep about 6 hours
- More frequent drowsy periods - Percentage of REM falls from 50% in infants to 20% in adults
- Slow wave sleep (stages 3 / 4) decreases with age
- Stage 1 and 2 sleep increases with age
Function of ARAS?
Important in arousal and wakefullness
What does lesion in ARAS cause?
Persistent somnolence or coma
Function Pontine REM center?
- Activates brain stem gaze centers responsible for rapid, conjugate eye movements during REM
- Induces hypotonia and increased autonomic activity
What controls REM and NREM sleep?
- REM and NREM sleep are promoted by preoptic area of
ventrolateral hypothalamus
What is hypothalamic suprachiasmatic nucleus?
“Biological clock”
- Controls circadian sleep-wake cycle
- Receives direct retinal input via optic chiasm, allowing environmental light stimuli to influence the “clock”
Cardiopulmonary sequelae sleep apnea?
- Frequent sleep apneas create nocturnal hypoxemia which in turn cause spulmonary hypertension or cardiac
arrhythmias
Pathology OSA?
Upper airway obstruction despite contraction of diaphragm and chest wall muscles
Pathology Narcolepsy?
- REM sleep occurring at inappropriate times
- Related to a deficiency of neurons in hypothalamus which release excitatory peptide hypocretin
Features narcolepsy?
- Narcoleptic attacks
- Cataplexy
- Sleep paralysis
- Visual hallucinations when falling asleep or waking up.
What is cataplexy?
Loss of muscle tone, for seconds - minutes in duration
- Often provoked by emotional triggers, such as an angry outburst, laughing at a joke or being “surprised”
- Slumps to ground because of REM hypotonia and may not speak well, yet breathes, stays awake, and recalls event
What is sleep paralysis?
REM hypotonia transiently preventing getting out of bed on wakening
Diagnosis narcolepsy?
Abnormally early onset REM as patient allowed to fall asleep several times (not in state of sleep deprivation)
