Exam 3: Sleep and The Circadian Rhythm Flashcards
REM Sleep
A sleep stage characterized by rapid eye movements, vivid dreaming, and brain activity similar to wakefulness.
Non-REM Sleep
Sleep stages without rapid eye movements, including stages 1-3; typically associated with physical restoration.
EEG
A technique that records electrical activity of the brain and is used to monitor sleep stages.
Stage 1 non-REM
The lightest sleep stage, marked by a transition from wakefulness to sleep with theta wave activity.
Stage 2 non-REM
A sleep stage characterized by sleep spindles and K-complexes; it is deeper than stage 1 but not the deepest.
Stage 3 non-REM
The deepest stage of non-REM sleep, also known as slow-wave sleep, with delta wave activity.
flip flop switch
A neural mechanism that helps regulate transitions between sleep and wake states, maintaining stability.
Ventrolateral preoptic nucleus
A cluster of neurons in the hypothalamus that promotes sleep by inhibiting wakefulness-promoting regions.
Recuperation Theory of Sleep
Proposes that sleep is necessary for the body to repair and restore itself.
Evolutionary Adaptation Theory of Sleep
Suggests sleep evolved to protect animals by keeping them inactive during dangerous periods.
Brain Plasticity Theory of Sleep
Proposes sleep is crucial for brain development and memory consolidation.
non-24 hour sleep-wake disorder
A circadian rhythm disorder where the internal clock is not aligned with the 24-hour day, leading to insomnia or daytime sleepiness.
narcolepsy
A sleep disorder characterized by uncontrollable episodes of falling asleep during the day.
Cataplexy
A symptom of narcolepsy involving sudden loss of muscle tone while awake, often triggered by emotions.
sleep paralysis
Temporary inability to move or speak while falling asleep or waking up.
Orexin
A neuropeptide that promotes wakefulness and stabilizes sleep-wake transitions; lacking in narcolepsy.
delayed sleep wake phase disorder
A circadian rhythm disorder where sleep is delayed by two or more hours, making it hard to wake at desired times.
Zeitgebers
External cues (like light and temperature) that help synchronize biological rhythms to the environment.
circadian rhythms
Biological processes that cycle roughly every 24 hours, such as the sleep-wake cycle.
circatidal rhythms
Biological rhythms tied to tidal cycles, typically around 12.4 hours.
infradian rhythms
Rhythms that occur less frequently than once per day, such as menstrual cycles.
Circannual rhythms
Biological rhythms that occur yearly, like seasonal breeding or migration.
Circalunar rhythms
Rhythms that follow the lunar cycle, about 29.5 days.
entrainment
The process of synchronizing a biological rhythm to an external cue.
chronotype
An individual’s natural preference for sleeping at a particular time of day (e.g., morning vs evening person).
Jet Lag
Disruption of the internal clock due to rapid travel across time zones.
suprachiasmatic nucleus (SCN)
A brain structure in the hypothalamus that serves as the master circadian clock.
intrinsically photosensitive retinal ganglion cells
Specialized retinal cells that detect light and send signals to the SCN to regulate circadian rhythms.
retinohypothalamic tract
A pathway connecting the retina to the hypothalamus, important for entraining the circadian clock.
clock genes
Genes that control the molecular mechanisms of the circadian rhythm.
melatonin
A hormone secreted by the pineal gland at night that promotes sleepiness.
blue wavelenghts of light
Light in the blue wavelength range (around 480 nm) that suppresses melatonin and promotes alertness.
Adenosine
A neurotransmitter that builds up during wakefulness and promotes sleep pressure.
Effects of Caffeine on Sleep
Caffeine blocks adenosine receptors, reducing sleep pressure and promoting alertness.
Effects of Alcohol on Sleep
Alcohol may initially promote sleep but disrupts sleep architecture and REM later in the night.
Effects of Cannabis on Sleep
Cannabis can reduce sleep latency but may alter sleep architecture and reduce REM sleep.
Social Jetlag
The mismatch between biological and social clocks, often due to late-night social schedules conflicting with early obligations.
