Topic 10: Sleep II: The Sleep-Wake Cycle

Sleep-Wake Cycle

The regular pattern of alternating periods of sleep and wakefulness.

Sleep

A naturally occurring state of reduced awareness and responsiveness that supports restoration and health.

Wakefulness

A state of alertness and conscious awareness of the environment.

Sleep Architecture

The overall structure and organization of sleep stages throughout the night.

Sleep Cycle

A complete progression through the stages of sleep that typically lasts about 90 minutes.

Non-Rapid Eye Movement Sleep (NREM)

The stages of sleep characterized by reduced brain activity and minimal eye movement.

Rapid Eye Movement Sleep (REM)

A stage of sleep associated with vivid dreaming and rapid eye movements.

NREM Stage 1 (N1)

The lightest stage of sleep that occurs as a person falls asleep.

NREM Stage 2 (N2)

A stage of sleep characterized by sleep spindles and K-complexes.

NREM Stage 3 (N3)

The deepest stage of sleep dominated by slow delta waves.

Deep Sleep

A stage of sleep important for physical restoration and recovery.

REM Sleep

A sleep stage associated with dreaming memory processing and heightened brain activity.

Sleep Onset

The transition from wakefulness to sleep.

Sleep Spindle

A brief burst of brain activity that occurs during NREM Stage 2 sleep.

K-Complex

A large brain wave that occurs during NREM Stage 2 sleep and may help protect sleep.

Electroencephalogram (EEG)

A recording of the brain's electrical activity.

Brain Waves

Patterns of electrical activity produced by groups of neurons.

Alpha Waves

Brain waves associated with relaxed wakefulness.

Beta Waves

Brain waves associated with active thinking and alertness.

Theta Waves

Brain waves associated with drowsiness and light sleep.

Delta Waves

Slow brain waves associated with deep sleep.

REM Atonia

A temporary paralysis of most skeletal muscles during REM sleep.

Dreaming

A series of thoughts images and sensations experienced during sleep.

Vivid Dreams

Detailed and emotionally rich dreams that commonly occur during REM sleep.

Sleep Regulation

The processes that control when and how long sleep occurs.

Homeostatic Sleep Drive

The increasing pressure to sleep that builds during wakefulness.

Circadian Rhythm

A biological clock process that helps regulate the timing of sleep and wakefulness.

Sleep Deprivation

A condition resulting from insufficient sleep.

Chronic Sleep Deprivation

Long-term lack of adequate sleep that can impair health and performance.

Microsleep

A brief involuntary episode of sleep occurring during wakefulness.

Sleep Debt

The accumulated effect of repeatedly getting insufficient sleep.

Sleep Quality

A measure of how restorative and uninterrupted sleep is.

Sleep Efficiency

The percentage of time spent asleep while in bed.

Arousal

Systems in the brain that promote wakefulness and alertness.

Reticular Formation

A brainstem network involved in regulating wakefulness and attention.

Hindbrain

A region of the brain involved in sleep regulation and basic life functions.

Memory Consolidation

The strengthening and stabilization of memories during sleep.

Learning and Sleep

Sleep enhances learning by supporting memory consolidation and neural plasticity.

Growth Hormone

A hormone released during deep sleep that supports growth and repair.

Physical Restoration

The repair and recovery processes that occur during sleep.

Cognitive Restoration

The recovery of mental functions that occurs during sleep.

Sleep Disorder

A condition that disrupts normal sleep patterns.

Insomnia

A sleep disorder characterized by difficulty falling asleep or staying asleep.

Sleep Apnea

A disorder involving repeated interruptions in breathing during sleep.

Narcolepsy

A disorder characterized by excessive daytime sleepiness and sudden sleep attacks.

REM Rebound

An increase in REM sleep following REM sleep deprivation.

Healthy Sleep

A pattern of sleep that supports physical mental and emotional wellbeing.