Module 23: Sleep Flashcards
Sleep
A periodic, natural loss of consciousness
different from unconsciousness from general anesthesia, hibernation, & comas
Circadian Rhythm
Our bodies roughly synchronize w/ the 24 hour cycle of day & night
- “Internal Biological Clock”
What does our circadian rhythm impact?
It impacts our sleep-wake cycles, temperature, hormonal and digestive cycles
When do our body temperature peak?
- as dawn nears (early morning)
- during the day/noon
- dips in the afternoon & evening
(temps rise and fall with the sun)
When do our thinking and memory improve?
Our thinking and memory improve as we approach our daily peak in circadian arousal
What may alter someone’s circadian rhythm?
Age and experiences
How do psychologists research biological rhythms that occur during sleep?
EEG records brain activity while sleeping
- varying wave patterns occur during sleep
What are alpha waves?
The waves records when you are awake but in a relaxed state.
- entering sleep
NREM
Non-rapid eye movement sleep
- all stage minus REM Sleep (1-3)
REM
Rapid eye movement sleep
- vivid dreams
- deepest stage of sleep (recurring sleep)
What is NREM-1 stage sleep?
- hallucinations (seeing or hearing things that aren’t there
- falling sensation or floating weightlessly
- some leg or arm jerks
- hypnagogic sensations (the hallucinations and sensations while falling asleep) may be incorporated into memories
What is NREM-2 stage sleep?
- 20 minutes of sleep
- sleep spindles : burst of rapid rhythmic brain-wave activity, and K-complexes (distinct wave)
- could be waken up but are now asleep
What is NREM-3 stage sleep?
- large slow wave sleep (delta waves)
- 30 minutes
- hard to awaken
How do we cycle through stages of sleep?
- start stage 1, stage 2, stage 3, stage 2, REM, repeat starting from stage 2
- some people go to stage 1 but that means they woke up in the middle of the night
- rollercoaster
What is REM sleep?
- Rapid eye movement sleep
- recurring sleep stage
- vivid dreams
- Paradoxical sleep: muscles are relaxed but other systems are active - can’t move
What physiological events occur during REM?
- heart rate rises, breathing rapid & irregular
- muscle paralysis occurs (some random twitches)
How does sleep change as we age?
As people age, sleep becomes more fragile with awakening common among older adults.
How do biology and environment interact in our sleep patterns?
Sleep patterns are genetically and culturally influenced
think school, work, etc.
Why do American students get less sleep than sleepers in other countries?
- earlier school start times
- increased extracurricular activities
- lack of parent-set bedtime
What three environmental factors play a role in our biological ability to sleep?
- modern electric lighting
- work shift
- social-media diversions
Suprachiasmatic nucleus (SCN)
- pair of cell clusters in the hypothalamus that control circadian rhythm
- responds to light - the SCN causes the brain’s pineal gland to decrease its production of melatonin in the morning and to increase it in the evening
How does the SCN react during the day?
The suprachiasmatic nucleus suppresses the pineal gland’s production of melatonin
How does the SCN react during the night?
The suprachiasmatic nucleus quiets down and allows the pineal gland to release melatonin into the bloodstream
What are the functions of sleep?
- protection: ancestors were better asleep in caves away from predators; don’t wander off cliffs (natural selection)
- recuperation: helps restore immune system and brain tissue; gives time for neurons to repair and pruning unused connections
- restoration and rebuilding: consolidates our memories by replaying recent learnings to strengthen neural activity
- feeds creative thinking: can inspire artistic or scientific achievements; boost thinking & learning
- supports growth: the pituitary gland releases human growth hormones necessary for muscle development (during slow wave sleep)
How long does the 1 sleep cycle last for?
90 minutes
What occurs during a normal night’s sleep?
NREM-3 sleep shortens & REM and NREm-2 sleep lengthens
What disrupts our circadian rhythm?
- too much light or not enough light (nigh-shift) caused desynchronization
