Sleep Physiology Flashcards
Describe non-REM sleep
3/4 adults sleep, at start of the night. Synchronised rhythmic EEG activity with partial relaxation of muscles - reduced cerebral blood flow, heart rate, BP and tidal volumes. Non- narrative dreams.
Describe REM sleep
Mostly at the end of the night, EEG shows fast activity with increased brain activity. Atonic muscles - except diaphragm and extraocular muscles. Increased blood flow and impaired thermal regulation - narrative dreaming
What is the most important type of sleep?
Non-REM, if sleep deprived non-REM will be predominant in recovery
What type of drug suppresses REM sleep?
Tricyclics
Name three processes involved in sleep
- homeostatic response
- emotional response
- circadian rhythm
What is homeostatic response involved in sleep onset?
Longer you are awake for the more sleepy you feel
What is emotional response in sleep onset?
Need to be relaxed and comfortable enough to sleep
What is circadian rhythm?
Body clock - 2 peak pattern, important in appetite and hormone secretion, 25 hours, impacted by light
How does light affect our body clocks?
Non-rod, non-cone ganglion cells project to the suprachiasmatic nucleus sensitive to a specific frequency of blue light - re-sets your body clock each day
What important processes occur in non-REM sleep?
Protein synthesis
Cell division and growth
What important processes are involved in REM sleep?
Consolidated memory, deletion of unnecessary memory files, immunocompetence maintenance, thermoregulation and conservation theory
State the prefrontal effects of lack of sleep
- irritable
- suspicious
- visual illusions
- concentration lapses
- microsleeps
- impaired alertness
What is an acceptable amount of sleep?
7-7.5 hours
Name three sleep disorders
- parasomnias
- narcolepsy
- insomnia
What are parasomnias?
Wakening with no memory
- sleep walking, talking, restless legs - non-REM
- no loss of muscle tone, simple behaviours in latter third of night -REM
What causes parasomnias?
Usually idiopathic but REM parasomnias can be a sign of parkinsons or dementias
What is narcolepsy?
‘Seized by somnolence’
What are the symptoms of narcolepsy?
- Daytime sleepiness
- Cataplexy - loss of muscle tone in emotion
- Hypnagogic hallucinations (as you fall asleep)
- Sleep paralysis
- REM behaviour disorder
State the investigations used in narcolepsy
Overnight polysomnography
Multiple sleep latency test - multiple naps with EEG muscle recording, very quickly enter REM sleep
In the first three months of insomnia what can be used as treatment?
Benzodiazapines
What is it called after 3 months of insomnia? How can it be treated?
Psychophysiological, brain becomes more active when they try to sleep - remove bad habits and use sleep deprivation methods
