CHP9: Importance of sleep AOS1

Question 1

Circadian rhythm

Answer 1

Changes to our physiological function or activity that occur as part of a cycle that lasts approximately 24 hours.

Question 2

Sleep

Answer 2

A cyclical progression that is regular and naturally occurring, through which different states are associated with different levels of alertness and psychological responses.

Question 3

Sleep-wake-cycle

Answer 3

The cycle of going from sleep to being awake within a 24-hour period.

Question 4

Reversibility

Answer 4

A person can be brought back to a waking state quickly (awoken) with a strong enough stimulus.

Question 5

Perceptual disengagement

Answer 5

How the sleeper has no awareness of the sensory stimuli in their external environment.

Question 6

Biological rhythms

Answer 6

Cyclic changes in bodily functions or activities that repeat themselves through time in the same order (e.g. circadian and ultradian rhythms).

Question 7

REM (rapid eye movement) sleep

Answer 7

A type of sleep where the sleeper experiences rapid eye movement beneath closed eyelids. The sleeper is virtually paralysed therefore most muscle movement is not possible, dreams are frequently recalled if woken during REM sleep, REM is a light stage of sleep as the brain is active and the sleeper can be woken easily.

Question 8

NREM (non-rapid eye movement) sleep

Answer 8

A type of sleep that is subdivided into four different stages, where the sleeper does not experience any rapid eye movement. Muscle movement is possible for the sleeper, dreams are not frequently recalled when woken during NREM sleep.

NREM1-2 are light sleep and the sleeper may not realise that they have been sleeping if woken during these stages. NREM3-4 are deep sleep and the sleeper is likely to feel drowsy and disorientated if woken during these stages.

Question 9

Sleep cycle

Answer 9

A proportion of a sleep episode in which the sleeper progresses through stages of REM and NREM sleep, lasting on average 90 minutes for humans.

Question 10

Sleep episode

Answer 10

The fullest duration of time spent in sleep.

Question 11

Infradian rhythms

Answer 11

Occur in cycles that last longer than 24 hours (e.g. menstrual cycle).

Question 12

Describe the function of the suprachiasmatic nucleus (SCN)

Answer 12

Receives information about the amount of incoming light from the eyes and adjusts our sleep-wake-cycle accordingly. It sends neural information to the pineal gland which secretes melatonin into the blood.

Question 13

Where is the suprachiasmatic nucleus (SCN) found?

Answer 13

Hypothalamus

Question 14

REM rebound

Answer 14

Catching up on REM sleep immediately following a period of lost REM sleep by spending more time than usual in REM sleep when next asleep.

Question 15

Evolutionary theory of sleep

Answer 15

A theory that proposes that sleep is adaptive and has evolved to meet specific survival needs.

Question 16

Restoration theory of sleep

Answer 16

A theory that proposes that sleep replenishes psychological and physiological functioning.

Question 17

What does the restoration theory of sleep suggest happens during REM sleep?

Answer 17

Replenishes psychological functioning;
Restores adequate neurotransmitter levels;
Maintaining neural pathways through stimulation;

Question 18

What does the restoration theory of sleep suggest happens during NREM sleep?

Answer 18

Replenishes physiological functioning;
Repairs damaged cells and tissues;
Detoxifies muscles;

Question 19

Sleep spindles

Answer 19

Brief bursts of higher frequency waves, 2-5 times a minute during stages 1-4 of sleep.

Question 20

K complex

Answer 20

Sudden sharp waveforms are usually only found during stage 2 of sleep. Triggered by noise and could be also involved in keeping a person asleep.

Question 21

NREM1 (Hypnogogic state)

Answer 21

Decrease in alpha waves, theta waves prominent. Psychological responses include breathing, heart rate, muscle tension and body temperature declining. NREM1 only lasts 5-10 minutes, sleep is light, and a person can easily be awakened.

This transition period from being awake to being asleep is called the hypnogogic state/ jerk.

Question 22

NREM2

Answer 22

Mostly theta waves with sleep spindles and K complex appear. Psychological responses include breathing regular, but heart rate, muscle tension and body temperature lowered. NREM2 is a deeper sleep than stage 1 but still easily woken up (e.g. from a loud noise).

Question 23

NREM3

Answer 23

Long slow delta waves begin to appear. Psychological responses include heart rate, muscle tension and body temperature continuing to be lowered. The sleeper becomes unresponsive to external stimuli, and difficult to wake.

Question 24

NREM4

Answer 24

Low slow delta waves dominate. Psychological responses include heart rate, muscle tension and body temperature lowered. Muscles are completely relaxed, it is difficult to wake and if woken it takes a long time to orient themselves, and the sleeper may be confused and groggy.

Sleepwalking, sleep terrors, and bed wetting often happens in this stage. Mental activity can occur in this stage in the form of a dream.

Question 25

Why is REM sleep important?

Answer 25

It replenishes psychological functioning, restores adequate neurotransmitter levels, and helps in maintaining neural pathways through stimulation.

Question 26

Why is NREM sleep important?

Answer 26

It replenishes physiological functioning, repairs damaged cells and tissues, and detoxifies muscles.

Question 27

Neonatal (1-15 days)

Answer 27

Require approximately 16 hours of sleep, with 50% REM and 50% NREM sleep proportions. They have irregular sleep-wake cycle, frequent waking during the night and have shorter sleep cycles.

Question 28

Infant (3-24 months)

Answer 28

Require approximately 13.5 hours of sleep with 35% REM and 65% NREM proportions. They have an irregular sleep-wake cycle (napping), and have lots of facial movement during REM.

Question 29

During childhood (2-14 years)

Answer 29

Require approximately 11 hours of sleep, with 20% REM and 80% NREM proportions. Additionally they spend more time in NREM 3, and 4.

Question 30

Adolescence (14-18 years)

Answer 30

Require approximately 8.5 hours of sleep, with 20% REM and 80% NREM proportions. They have delayed sleep onset (1-2hours), are more tired (sleep deprived), and spend less time in NREM 3+4 in later stages.

Question 31

Adulthood (18-75 years)

Answer 31

Require approximetley 6-8 hours of sleep with 20% REM and 80% NREM proportions. They have an earlier sleep onset, decrease in the number of sleep episodes, and have a gradual loss of NREM stages 3, and 4.

Question 32

Old age (75+ years)

Answer 32

Require approximately 5-6 hours of sleep with 20% REM and 80% NREM proportions. They experience frequent awakenings and are not getting NREM stages 3, and 4.