Consciousness & Sleep – Revision Flashcards

Flashcards covering key vocabulary for consciousness, sleep stages, brainwaves, lifespan changes, circadian disorders, effects of sleep loss, zeitgebers and important exam command terms.

Consciousness

Awareness of one’s thoughts, feelings and environment at any given moment.

Normal Waking Consciousness (NWC)

State of clear, organised alertness with high awareness of internal and external environments.

Altered State of Consciousness (ASC)

Any condition of consciousness that differs noticeably from NWC in awareness and experience.

Psychological Construct

A concept that exists and can be inferred from behaviour and physiological changes but cannot be directly observed.

Sleep

A naturally recurring ASC characterised by reduced awareness, muscle activity and responsiveness to external stimuli.

REM Sleep

Stage of sleep with rapid eye movements, brainwave activity like wakefulness, vivid dreaming and muscle paralysis.

NREM Sleep

Non-rapid eye movement sleep comprising three stages and making up about 75–80 % of a night’s sleep.

Circadian Rhythm

A 24-hour physiological cycle regulating sleep-wake patterns and other bodily functions.

Ultradian Rhythm

A biological rhythm shorter than 24 h, e.g. the 90-minute sleep cycle.

Sleep Cycle

A 90-minute sequence of NREM and REM stages; about five cycles occur in an eight-hour sleep.

NREM Stage 1 (N1)

Light transitional sleep where physiological responses begin to slow; easy to wake.

NREM Stage 2 (N2)

Light sleep with further slowing of body functions; contains sleep spindles and K-complexes; most frequent stage.

NREM Stage 3 (N3)

Deep or slow-wave sleep with delta waves, lowest physiological activity and highest arousal threshold.

Average Sleep Episode

Typical night sleep of ~8 h containing five 90-minute cycles of NREM and REM sleep.

Hypnogram

A line graph plotting stages of sleep (depth) against time across a sleep episode.

Beta Waves

High-frequency, low-amplitude brainwaves linked to alert, focused wakefulness.

Alpha Waves

Relatively high-frequency, low-amplitude waves associated with relaxed wakefulness or light meditation.

Theta Waves

Medium-frequency, high-amplitude waves evident in N1, dreaming and deep meditation.

Delta Waves

Lowest-frequency, highest-amplitude waves dominant in N3 deep sleep.

Sleep Spindle

Short burst of high-frequency brain activity in N2 indicating memory consolidation.

K-Complex

Single large, high-amplitude wave in N2, thought to suppress arousal and aid memory.

Muscle Atonia

Complete loss of voluntary muscle tone experienced during REM sleep.

REM Proportion

REM comprises roughly 20–25 % of total nightly sleep.

NREM Proportion

NREM comprises roughly 75–80 % of total nightly sleep.

Newborn Sleep Pattern

14–17 h daily; ~50 % REM, 50 % NREM; essential for rapid brain growth.

Child Sleep Pattern

10–12 h daily; ~25 % REM, 75 % NREM; circadian rhythm shifts earlier as naps disappear.

Adolescent Sleep Pattern

8–10 h needed; ~20 % REM; circadian phase delay causes later sleep onset.

Adult Sleep Pattern

7–9 h; ~20 % REM; lifestyle factors (work, parenting) can fragment sleep; N3 begins to decline.

Elderly Sleep Pattern

6–7 h; minimal or absent N3, increased awakenings; circadian phase advance and lower melatonin.

Delayed Sleep Phase Syndrome (DSPS)

Circadian disorder where sleep onset and wake times are delayed by ≥2 h compared with conventional times.

Advanced Sleep Phase Disorder (ASPD)

Circadian disorder where sleep onset and wake occur ≥2 h earlier than typical.

Shift Work Sleep Disorder (SWSD)

Sleep difficulties and excessive sleepiness resulting from working rotating or overnight shifts.

Affective Functioning

Emotional regulation; impaired by sleep deprivation leading to heightened irritability and mood swings.

Behavioural Functioning

Observable actions; sleep deprivation causes slower task completion, risk-taking and reduced productivity.

Cognitive Functioning

Mental processes; sleep loss impairs attention, memory, decision-making and problem-solving.

Zeitgeber

External cue, such as light, that synchronises circadian rhythms.

Suprachiasmatic Nucleus (SCN)

Hypothalamic ‘biological clock’ that regulates timing of the sleep-wake cycle using light information.

Melatonin

Hormone released by pineal gland; secretion increases in darkness, promoting sleepiness.

Light as a Zeitgeber

Strongest environmental cue; inhibits melatonin in bright light and stimulates its release in darkness.

Caffeine and Sleep

CNS stimulant that suppresses melatonin, raises heart rate and can delay sleep onset for 4–6 h.

Alcohol and Sleep

Induces drowsiness but fragments second-half sleep, reducing overall quality and increasing awakenings.

Core Body Temperature

Drops prior to sleep; falling temperature signals SCN to facilitate melatonin release and sleep onset.

Circadian Phase Delay

Shift of sleep-wake cycle to later times, typical in adolescence and DSPS.

Circadian Phase Advance

Shift of sleep-wake cycle to earlier times, common in older adults and ASPD.

Command Term: Define

Provide a clear, precise and accurate meaning of a term.

Command Term: Evaluate

Judge, assess and weigh the merits of a concept or procedure using evidence.

Command Term: Compare

Point out or measure the similarities between two concepts.

Command Term: Outline

Give the main points or facts, leaving out minor details.

Command Term: Justify

Provide reasons or examples, often using scenario data, to support a point.

Command Term: Identify / Name / Classify

Recognise and label a required item, concept or category.