6 the demand for sleep Flashcards

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1
Q

consciousness

A

awareness of smt either internal or external to ourself, incl. objects and events in the external world, our sensations, mental experiences & our existence at any given moment

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2
Q

normal waking consciousness (NWC)

A
  • associated w being awake
  • aware of objects & events in the external world
  • aware of sensations & mental experiences
  • aware of feelings
  • aware of normal passage of time
  • constantly changes throughout time awake
  • not a single state – varies throughout the day in relation to how alert we are
  • can incl. lvls of heightened or lowered alertness
  • approx. 2/3 of each 24-hour day/night cycle

e.g. Awake at school, driving a car, reading a book

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3
Q

altered state of consciousness (ASC)

A
  • associated w being in states that are diff to NWC
  • changes in awareness of objects & events in the external world
  • mental processing of internal & external stimuli shows distinguishable, measurable changes
  • possible less inhibition or self control
  • exaggeration of emotional response
  • distortion in perception of passage of time
  • altered awareness of sensation & perception
  • approx. 1/3 of each 24-hour day/night cycle

e.g. Sleep (naturally occuring), anaesthesia (induced)

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4
Q

states on consciousness (total awareness → total lack of awareness)

A
  • focused attention
  • normal wakefulness
  • daydreaming
  • meditative state
  • hypnotised
  • asleep
  • anaesthetised
  • coma
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5
Q

focused attention

A

highly focused & acutely aware of some aspect of one’s internal or external environment

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6
Q

normal wakefulness

A

naturally occurring SC associated w being awake + aware of objects in the external world, sensations, mental experiences & own existence

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7
Q

daydreaming

A

naturally occurring ASC in which attention shifts from external stimuli to internal thoughts, feelings & imagined scenarios

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8
Q

meditative state

A

intentionally induced ASC characterised by deep state of relaxation achieved thru use of meditation technique

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9
Q

hypnotised

A

intentionally induced ASC characterised by responsiveness to suggestions made by the hypnotist & the subjective experience of consciousness

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10
Q

asleep

A

naturally occurring ASC characterised by perceptual disengagement from & unresponsiveness to the environment

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11
Q

coma

A

unintentionally induced ASC where there is a complete or almost complete loss of all basic functions of consciousness, incl. loss of awareness

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12
Q

anaesthetised

A

intentionally induced ASC characterised by unconsciousness when general anaesthesia is used

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13
Q

psychological construct

A

a concept that is ‘constructed’ to describe a specific ‘psychological’ activity that is believed to occur but cannot be directly observed – measured indirectly using:

  • info provided by individuals & groups (e.g. self-reports)
  • behaviour (e.g. responses by participants observed during sleep)
  • physiological changes that can be measured (e.g. recordings of brain wave activity)
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14
Q

measurement of psychological responses associated with sleep

A
  • EEG (brain waves)
  • EMG (muscle tension)
  • EOG (eye movements)
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15
Q

Electroencephalography (EEG)

A

a method of studying brain waves produced during sleep

  • an electroencephalograph is used to detect, amplify & record the electrical activity thru electrodes manually placed at various points on the scalp
  • electrodes are attached to the surface of the scalp to detect summative electrical activity produced by neurons in the cerebral cortex
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16
Q

frequency and amplitude

A

frequency: number of brain waves per second
amplitude: intensity of brain waves

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17
Q

Beta pattern

A

Associated w alertness & intensive mental activity during normal waking consciousness. Beta waves are also present when dreaming during a period of REM sleep

  • high frequency (fast), low (small) amplitude
18
Q

Alpha pattern

A

When we are awake and alert but mentally and physically relaxed and internally focused, the EEG shows a predominantly alpha brain wave pattern

  • high frequency (slower than beta waves), low amplitude (slightly larger than beta waves)
19
Q

Theta pattern

A

Most commonly produced when we are very drowsy, such as when falling asleep or just before waking. They may also be produced when awake and engaged in creative activities.

  • medium frequency (slower than alpha & beta waves), mixture of high & low amplitude waves
20
Q

Delta pattern

A

Most commonly associated with deep, dreamless sleep or unconsciousness.

  • lowest frequency, highest amplitude
21
Q

Electromyography (EMG)

A

a method of studying the electrical activity of muscles produced during sleep

  • detect, amplify & record the electrical activity of muscles
  • recordings show the strength of electrical activity occurring in muscles which indicates changes in movement & tension
  • when falling asleep, we become less alert as we drift into deeper stages of sleep
  • sleep studies using EMG recordings show that
    while this is occurring, our muscles progressively
    relax & there is less movement
  • the higher the level of muscular activity & tone, the more alert we tend to be and vice versa
22
Q

Electro-oculargraphy (EOG)

A

a method of measuring eye movements or eye positions during sleep

  • detect, amplify & record the electrical activity in eye muscles that control eye movements
  • records of the EOG are displayed as line graphs, similar to those produced by the EEG and EMG
  • most commonly used to measure changes in eye movements over time during different types + stages of sleep & while dreaming
  • sleep research studies using an EOG have clarified the distinction b/w the 2 different types of sleep; REM & NREM sleep
23
Q

Sleep diary

A

a ‘log’ used to self-record + self-report sleep & waking time activities over some time, usually 1 week or more

  • often used in conjunction with physiological measures to support the assessment of sleep disturbances or disorders, particularly their nature, severity and possible causes

e.g. records may be kept of:
- time when trying to fall asleep
- time when it is believed sleep onset occurred
- number, time & length of awakenings during sleep

24
Q

self-report sleep diaries

A

subjective measure b/c they are based on or influenced by personal feelings or interpretations

  • subjective data is often biased, varies from person to person, day to day from the same person & isn’t always entirely accurate
  • in contrast, an objective measure such as an electronic recording device is impartial & not subject to personal opinion or interpretation
25
Q

video monitoring

A

monitor + record externally observable physiological responses throughout a sleep episode, inclu. behaviours when falling asleep & when waking

responses that may be targeted include:
- changes in posture or body position
- amount of ‘tossing and turning’
- sleep-related breathing problems
- what happens when awakening from a nightmare
- behaviours associated w sleepwalking

These types of responses can be examined together with those of other types of recordings, then linked to different sleep stages, sleep types or the specific aspect of sleep under investigation

26
Q

4 internal biological mechanisms that influence the regulation of our sleep-wake patterns

A
  • circadian rhythm
  • ultradian rhythm
  • suprachiasmatic nucleus (SCN)
  • melatonin
27
Q

circadian rhythm

A

biological rhythm that occur as part of a cycle for approx 24 hrs

  • sleep-wake cycle originates w/in each individual ∴ referred as endogenous
  • influenced by exogenous cues to be in-sync w 24-hr day-night cycle
  • our preference to sleep at night & be up during the day is tied to a circadian rhythm – regulated by SCN
28
Q

body temperature during a circadian rhythm

A
  • lowest when asleep
  • highest when awake

drowsiness increases as body temperature decreases (& vice versa)

29
Q

ultradian rhythm

A

biological rhythm that occur as part of a cycle shorter than 24 hrs

diff ultradian rhythms: heart rate, respiration rate, hunger, hormone secretion, sleep stages

  • generally, a complete sleep cycle lasts for abt 90 mins.
  • h/w duration + no. of cycles are influenced by many variables e.g. age, health & environmental cues
30
Q

suprachiasmatic nucleus (SCN)

A

master biological clock located in the hypothalamus that regulates the timing & activity of sleep-wake cycle

  • when SCN receives info abt amount of incoming light from eyes, it adjusts sleep-wake cycle by sending neuronal msgs to nearby pineal gland to secrete more or less melatonin into the blood
31
Q

melatonin

A

hormone that is involved in initiation of sleep & regulation of the sleep-wake cycle

  • produced by the pineal gland in the brain & released into the blood stream to reach every organ in the body
  • higher melatonin lvl is associated w greater drowsiness and vice versa
32
Q

NREM and REM sleep

A
  • NREM (75–80%)
  • REM (20–25%)
33
Q

similarities & differences b/w NREM and REM sleep

A

similarities:

  • occur in mammals and birds

differences:

  • NREM sleep has stages, whereas REM sleep does not
  • NREM sleep is described as sleep w a relatively inactive brain in a body that can move, whereas REM sleep is sleep w an active brain in a paralysed body
34
Q

hypnogram (sleep graph)

A

shows that NREM and REM sleep periods alternate throughout a typical episode in a cyclical way

35
Q

complete sleep cycle

A
  • a period of NREM sleep w transitions b/w its 3 stages (not necessarily all its stages) & a period of REM sleep
  • REM sleep in every cycle, even if only for a short time
  • we also have very brief arousals many times during a nightly sleep episode
  • generally, for a healthy young adult who sleeps well, each cycle is repeated 5/6 times each night
36
Q

what happens as the sleep episode progresses

A
  • stage 3 deep sleep may not be experienced
  • REM sleep periods tend to get longer & be closer tgt
  • stage 1 may be skipped at diff times during the episode, most commonly js before the first REM period
  • there may be brief awakenings during the episode
37
Q

variations of NREM and REM sleep in younger adults

A
  • stage 3 deep sleep tends to predominate in NREM period during the first half of the sleep episode
  • as night progresses, stage 2 begins to account for the majority of NREM sleep & stage 3 may disappear
38
Q

NREM sleep

A
  • reduction in physiological activity
  • each successive stage indicates deeper sleep
  • as sleep gets deeper – brain waves = slower + bigger, breathing & heart rate = slows , bp = drops
39
Q

sleep onset

A

transition period from being awake to being asleep

40
Q

sleep latency

A

amount of time it takes to fall asleep

41
Q

NREM stage 1 (N1)

A
  • relatively light sleep
  • physiological changes: decrease in breathing + heart rate, body temp & muscle activity (may experience hypnic jerks)
  • lasts abt 5 mins
  • easily awakened bc low arousal, sometimes feel as if we haven’t slept at all
42
Q

NREM stage 2 (N2)

A
  • moderate sleep
  • physiological changes: continued decrease in breathing + heart rate, body temp, muscle activity & eye movement stops
  • brain produces sleep spindles (brief bursts of electrical activity)
  • lasts abt 25 mins
  • we spend more of our repeated sleep cycles in N2