Sleep Flashcards
Define circadian rhythm
Natural internal process that regulates the sleep–wake cycle within a 24-hour period.
Define sleep-wake homeostasis
Assists the body to remember to sleep after a given time.
Why is sleep needed?
- Provides new neural pathways for learning and memorization
Define sleep deprivation
When the body does not meet its biologically needed sleep requirement, either chronically or acutely
Function of cerebral cortex
Receives sensory input from the thalamus
Transmits info from short-term to long-term memory
Function of brainstem
Control rapid eye movement (REM) sleep
GABA produced here (reduces arousal center activity)
Function of hypothalamus
SCN regulates circadian rhythm through light exposure
GABA produced here (reduces arousal center activity)
Function of thalamus
- Transmits sensory info to cerebral cortex
- Blocks out distractions during sleep
- In REM, transmits images, sounds, and sensations which influences dream content
Function of pineal gland
Makes melatonin
How many stages of REM do we have per night?
4-6
What happens during REM?
- low muscle tone (causes eye movements)
- Dreaming
How many cycles of NREM per night?
4-6
What are the sleep stages?
Wake stage
Stage 1
Stage 2
Stage 3
Stage 4
Wake Stage
First stage of sleep
More alpha than beta waves
Alpha (8-12 Hz) waves: awake but relaxed, eyes closed
Beta (12-30 Hz) waves: alertness and engagement
Stage 1
Lightest sleep
1–5 minutes; 5% of total sleep
Regular breathing
Diminished eye and muscle movement
Electrical activity slows; >50% of alpha waves are exchanged for low-amplitude mizxed-frequency waves
Stage 2
Deeper sleep
50% total sleep
No eye movements, heart and breathing rate decrease, muscles relax
Sleep spindles = sudden burst of oscillatory activity 0.5-1.5 seconds
K-complex=electrical waveform
Stage 3
Deepest sleep
15% total sleep; lasts up to 40 min.
Muscles, bones, and tissues repair, immune system strengthens
Delta waves
Stage 4
REM; dreaming stage
20–25% total sleep
Heart rate and breathing increase
Muscles continue to relax (reduced muscle tone prevents the person from acting out dreams)
Can last up to 1 hr
Sleep cycle of newborns and infants
NREM and REM every 45–60 min
Mostly stage 3
Until 3 months, half of sleep is REM sleep
Sleep cycle of adults
Sleep cycles repeated 4 to 5 times
45-55% in stage 2
10-20% stage 3
20-25% REM
Sleep cycle of older adults
Decrease in stage 3 and increase in stage 2
Wake more and take longer to fall asleep
number of hours of sleep for newborns
14-17
number of hours of sleep for infants
12-15
number of hours of sleep for toddlers
11-14
number of hours of sleep for preschoolers
10-13
number of hours of sleep for school age kids
9-11
number of hours of sleep for adolescents
8-10
number of hours of sleep for adults
7-9
number of hours of sleep for older adults
7-8
define total sleep deprivation
losing entire nights sleep or staying awake for 24+ hours
partial sleep deprivation
lessened sleep hours
insomnia
ongoing inability to sleep despite having the opportunity
Central sleep apnea
Reduction in the brain’s signals to respiratory muscles
Often caused by opioid overdose and heart failure
Obstructive sleep apnea
Upper airway collapse and waking
Daytime sleepiness and fatigue
Narcolepsy
- Chronic sleep condition characterized by sudden sleepiness and sudden periods of sleep.
- May have sleep paralysis and vivid dreams
- May have cataplexy (a brief loss of voluntary muscle tone triggered by an emotional stimulus)
NT1 vs Nt2 narcolepsy
- NT1 (with cataplexy; caused by lack of hypocretin which is produced by the hypothalamus and causes alertness)
- NT2 (without cataplexy)
Hypersomnia
A disorder of excessive daytime fatigue without improvement after more sleep
Most common med for sleep
Non-benzodiazepine hypnotics
GABA agonists/benzodiazepines
Clonazepam, lorazepam
Cause drowsiness
Non-benzodiazepine hypnotics
Z-drugs
Can cause hallucinations, memory loss, GI upset
