Sleep Flashcards
Ways to define sleep?
Duration
Timing
Quality
Having a sleep disorder increases mortality by how much?
1.5 x
What is the body’s master circadian clock?
ie control center for sleep and arousal
Where is it located?
Suprachiasmatic nucleus (SCN)
in the hypothalamus
oscillator and pacemaker
What are ‘zeitgebers’?
internal and external stimuli
- that entrain the master clock
Most potent –>Light
Melatonin is produced by what?
What does it do?
Pineal gland
- night hormone
Promotes night time things and sleep
Melatonin peaks when?
30 mins before anticipated bedtime
Plateaus for rest of night
Rapidly decreases close to subjective day
Melatonin ceases at first light exposure, approx 30 min after wake
What does melatonin inhibit?
SERT
- sodium dependent serotonin transporter
Physiologic changes induced by healthy sleep?
Lower cortisol
Lower glucose
Greater insulin sensitivity
Higher daytime leptin
- reduced food seeking behav
Healthy sleep impact on CV disorders
Lower sympathetic tone
Low BP
Greater night peripheral perfusion
Core body temp cooling (night)
Increased stamina
Faster CV recovery time
Appropriate duration and timing of REM is associated with…?
- enhanced learning and memory
- faster cognitive processing
- greater extinguishment of anxiety and fear
When should you order a PSG study?
ie for which disorders?
Breathing-related sleep disorder
Narcolepsy
Nocturnal seizures
Periodic limb movement disorder
REM sleep behaviour disorder
For what conditions is a PSG not required?
Circiadian rhythm disorder
Insomnia disorder
NREM partial arousal parasomnia
Nightmare disorder
Restless legs syndrome
NREM stages
Stage 1.
- slow brain waves
- 2% of night
- enter sleep
Stage 2.
- 50% of night
- logical dreams
Stage 3.
- 20-25% of night
- deep sleep (good for memory)
- delta waves
- first half of the night
- restorative
Features of NREM sleep?
- sensation/perception
- thoughts
- movement
sensation and perception
- dulled/absent
thoughts
- logical and perseverative
movement
- episodic and involuntary
Features of REM sleep?
- sensation/perception
- thoughts
- movement
sensation and perception
- vivid
- internally generated
thoughts
- illogical and bizarre
movement
- inhibited