CHAPTER 6 Sleep pages

Question 1

Circadian rhythms

Answer 1

daily biological cycles

Question 2

Most circadian rhythms are regulated by the brain’s

Answer 2

superchiasmatic nucleus (SCN)

SCN neurons have genetically programmed cycle of activity and inactivity, functioning like a biological clock

They link to the tiny pineal gland which secretes melatonin

Question 3

what secretes melatonin?

Answer 3

pineal gland

Question 4

melatonin

Answer 4

a hormone that has a relaxing effect on the body

Question 5

SCN neurons become active …..and are inactive when …

Answer 5

during the day SCN neurons become active during the daytime and reduce the pineal gland’s secretion of melatonin, raising body temperature and heightening alertness. At night, SCN neurons are inactive, allowing melatonin levels to increase and promoting relaxation and sleepiness

Question 6

The eyes have a neural connection to the

Answer 6

SCN and after a nights sleep, the light of day increases SCN activity and helps reset your 24 hour body clock

Question 7

In experiments where people could not tell whether it was day or night outside drifted into a

Answer 7

free running circadian rhythm which is longer than 24 hours

Question 8

Environmental changes can disrupt our ….

Answer 8

circadian rhythms

Question 9

Fly east vs flying west

Answer 9

Flying east, you lose hours from your day and flying west, extends your day to more than 24 hours

the body naturally adjusts about one hour or less per day to time-zone changes

typically people adjust faster when they are flying west, presumably because lengthening the travel day is more compatible with out natural free-running circadian cycle

Question 10

Night shift work

Answer 10

Daytime becomes bed time and you may sleep less than you did before

Night shift body clock is promoting sleepiness

Over time you may become fatigued, stressed and more accident prone

On days off, reverting to a typical day-night schedule will disrupt any hard-earned circadian rhythm adjustments you have made

Question 11

Seasonal affective disorder

Answer 11

a cyclic tendency to become psychologically depressed during certain seasons of the year

in cooler climates, SAD tends to begin in autumn or winter, when there is less daylight, and then shifts to spring

Sensitive light, so use light therapy

Question 12

Beta waves

Answer 12

when you are awake and alert

Question 13

Alpha waves

Answer 13

feeling relaxed and drowsy, your brain wave slow down

Question 14

What happens roughly every 90 minutes whilst asleep?

Answer 14

we cycle through different stages in which brain activity and other physiological responses change in a generally predictable way

Question 15

As sleep begins…

Answer 15

brain wave pattern becomes more irregular and slower theta waves increase and you are now in stage 1, a form of light sleepf rom which you can easily be awakened. Probably spend just a few minutes in stage 1 during which some people experience dreams, vivid images and sudden body jerks

Question 16

As sleep becomes deeper

Answer 16

sleep spindles which are periodic 1- to 2- second bursts of rapid brain wave activity begin to appear. Sleep spindles indivate that you are now in stage 2. Your muscles are more relaxed, breathing and heart rate are slower and you are harder to awaken

Question 17

As sleep becomes even deeper…

Answer 17

Sleep deepens as you move to stage 3, marked by the regular appearance of very slow and large delta waves. As time passes, they occur more often and when delta waves dominate EEg pattern you have now reached stage 4 sleep. Collectively termed slow wave sleep. You body is relaced, activity in various parts of the brain has decreased, you are hard to awaken and you may have various dreams

Question 18

together stage 3 and 4 sleep are often referred to as

Answer 18

slow wave sleep

Question 19

After 20-30 minutes of stage 4 sleep…

Answer 19

your eeg pattern changes as you go back through stages 3 and 2, spending a little time in each. Overall, within 60-90 minutes of going to sleep you have completed a cycle of stages : 1-2-3-4-3-2. At this stage a remarkably different sleep stage ensues …REM sleep

Question 20

REM Sleep

Answer 20

Characterised by rapid eye movements (REM), high arousal and frequent dreaming

ALthough each cycle through sleep takes an average of 90 minutes, as the hours pass, stage 4 and then 3 drop out and REM periods become longer

Question 21

REM sleep decreases dramatcally during

Answer 21

infancy and early childhood but remains relatively stable thereafter

Question 22

Randy Gardener

Answer 22

Stayed awake for 11 days

first few days - became irritable, forgetful and nauseated

by the fifth day - periods of disorientation and mild hallucinations

last 4 days - finger tremours and sleered speech

when randy finally went to be he slept for almost 15 hours the first night and returned to his normal amount of sleep within a week

in general, it takes several nights to recover from extended sleep deprivation and we do not make up for all the sleep time that we have lost

Question 23

Many researchers believe that the sleep stages help us

Answer 23

remember important information by enhancing memory consolidation, a gradual process by which the brain transfers information into long term memory

Question 24

Insomnia

Answer 24

Refers to chronic difficulty in falling asleep, staying asleep or experiencing restful sleep

Question 25

Narcolepsy

Answer 25

involves extreme daytime sleepiness and sudden, uncontrollable sleep attacks that may last from less than a minute to an hour

Question 26

Antidepressent drugs suppress

Answer 26

REM sleep