Sleep-Wake disorders- exam 3

Question 1

What is the etymology of the word circadian

Answer 1

Latin: ‘crica’ and ‘diem’ means ‘about a day’

Question 2

why do organisms have intrinsic time-keeping systems

Answer 2

• Synchronize our body functions
• many mammalian cells, organs, & tissues have rhythmic activity
• synchronize across tissues, organs, and the body for optimal functioning
• in mammals, 5-10% of the genome is rhymically transcribewd (many at night)

Question 3

why do we match behaviors to the light/dark cycle of the planet

Answer 3

Active under optimal conditions (light)
Inactive: when moving about would be dangerous (dark):
- conserving energy
- restoring brain glycogen stores
- producing protiens and building up tissues
- secreting growth hormones and gonadotropins
- memory consolidation

Question 4

why must we adjust the intrinsic time-keeping system (why is not set for a standard 24 hour cycle)

Answer 4

in humans the free running clock is 24.5 hours. The light must shift the animal’s clock each day by an amount equal to the difference between their intrinsic free-running period and the 24-hour period of the lighting cycle

Question 5

what signal adjusts our time keeping system

Answer 5

retinal detection of light via melanoplasin in speical retinal ganglion cells (M1 ganglion cells)

Question 6

what is the intrinsic period of the ‘free-running’ circadian oscillator for humans

Answer 6

24.5 hours

Question 7

what is the specific brain structure of the mammalian circadian timing system and in what larger brain system is it located

Answer 7

The suprachiasmatic Nucleus: a pair of small brain structures in the anterior hypothalamus just above the point where the optic nerves cross

Question 8

what type of cell in the retinal is responsible for adjusting our 24 hour circadian rhythym. What type of light does it respond to and where does it project?

Answer 8

M1 ganglion cell- responds to blue light

Question 9

what substance does the pineal gland secreate at night

Answer 9

melatonin

Question 10

what are the two main neurochemicals involved in the sleep/wake cycle

Answer 10

Orexin and GABA

Question 11

what are the 2 systems that regulate sleep

Answer 11

Circadian time and Homeostatic pressure

Question 12

when does our circadian rhthym cause us to sleep

Answer 12

it is a sleep independent process- it is tied to time of day.
provides:
- day time awake signal
- nighttime decrease activity and sleep signal
- post-prandial sleepiness- after meals

Question 13

what causes the homeostatic system to make us sleep

Answer 13

sleep propensity or sleep need
- becomes higher as a person remains awake for longer
- while we are awake adenosine levels rise.
- increasing sleep deprivation results in higher brain concentrations of adenosine
- a person who sleep deprived requires extra sleeping time for sleep prpensity to dissipate

Question 14

what chemical builds up in the brain during sleep

Question 15

what is the ‘Opponent Process Theory’ of sleep

Answer 15

alertness affected by opposing two biological factors circadian time and homeostatic pressure
circadian time:
- provides an arousal signal
- reaches a peak in late afternoon/early evening opposes the sleep prpensity signal
Homeostatic pressure:
- time spent awake
- increasing time spent awake produces greater drive to sleep

Question 16

what happens in individuals who do shift work

Answer 16

their biorhythms remain entrained to 24 hour day - results in performance deficits and health stressors
increased time and intensity of 2nd night sleep

Question 17

what does caffeine do

Answer 17

acts as an adenosine receptor antagonist and makes our brain less susceptible to the drowse-inducing effects of adenosine

Question 18

what is the “flip-flop” switch theory

Question 19

what neurotransmitters go on the sleep side and which ones go on the awake side

Answer 19

Sleep:
- VLPO
- GABA
Awake:
- orexin
- brain stem LC and Raphe
- norepinephrine and 5-HT

Question 20

what are developmental differences seen in infants & children, and in the elderly

Answer 20

Newborns: sleep 17-18 hours a day (sleeping 3-4 hour sessions)
Toddlers: sleep in a diurnal (twice daily) pattern- single daytime nap and nighttime sleep
6 year olds: consolidate into a single sleep period- 10-12 hours nocturnal sleep
adolescents: prone to later “phase dealy” stay up late and sleep late (night owl)
young adult: 6-8 hours
Elderly: have early ‘phase advance’ go to bed early and get up early. Diminished quality and duration of sleep: awaken more easily

Question 21

what are nightmares vs. night terrors and in what sleep stages do they occur

Answer 21

nightmares occur in stage 5 of sleep (same stage as REM), night terrors occur in sleep stage 4 (during delta wave sleep). You usually remember nightmares (like regular dreams). You may have physical signs of fear and stress during a night terror but you do not remember it when you wake up.

Question 22

when does sleep walking occur

Answer 22

sleep walking occurs during the 4th stage of sleep (delta waves)

Question 23

are sleep problems a major issue in the US (what % of individuals have sleep disorders)

Answer 23

35-40% of the adult population experiences sleep problems

Question 24

what is insomnia and stress insomnia

Answer 24

Insomnia: Trouble going to sleep or staying asleep.
Stress insomnia: Can increase brain aminergic activity (NE, DA, 5-HT) adn shift brain to hyperarousal. stress, disease or genetic predisposition

Question 25

table 2. pg. 493: DSM-5 criteria for insomnia disorder

Answer 25

A. a predominant complaint of dissatisfaction with sleep quantity or quality associated with one + of the following symptoms:
1. difficulty initiating sleep
2. difficulty maintaining sleep
3. early mornign awakening with inability to return to sleep
B. the sleep disturbance causes clinically insignificant distress or impairment in social, occupational, educational, academic, or other important areas of behavioral functioning
C. difficulty occurs at least 3 nights per week
D. difficulty is present at least 3 months
E. difficulty occurs despite adequate opportunities to sleep
F. not better explained by and does not occur exclusively during the course of another sleep-wake disorder
G. not attributable to physiological effects of a substance
H. coexisting disorders/medical conditions do not adequatley explain the predominant complaint of insomnia

Question 26

how is insomnia treated

Answer 26

• sleep restriction therapy
• CBT
• medications including: antidepressants, antihistamines, tryptophan, delta-sleep-inducing-peptide (DSIP), melatonin, and benzodiazepines (GABA agonist), orexin receptor blocker

Question 27

what is narcolepsy and what sleep stage is it linked to

Answer 27

Narcolepsy is triggered by excitement and positive emotions; it is an abrupt drop into REM sleep

Question 28

what animal was used for research in the discovery of the gene linked to narcolepsy

Answer 28

dogs

Question 29

what type of receptor does the narcolepsy gene code for

Answer 29

Orexin

Question 30

the treatment for narcolepsy involves ____ drugs targeted at improving sleep and ____ drugs targeted at staying awake

Answer 30

GABA agonist, stimulants

Question 31

what is sleep apnea and how is it treated

Answer 31

sleep apnea is cessation of breathing for > 20 seconds or cessation for 10 seconds with low resp. rate and a drop in O2 and heart rate.
Central sleep apnea is normla decline in drive from respiratory brain center during sleep. An exaggeration of this can produce sleep apnea.
Obstructive sleep apnea is mechanical collapse and compression of airway.

Question 32

Define circadian sleep disorders

Answer 32

abnormalities in length, timing, and/or rigidity of the sleep-wake cycle relative to the day-night cycle.
- delayed sleep phase disorder
- advanced sleep phase disorder
- non-24 sleep-wake disorder
- shift-work disorder

Question 33

what is advanced sleep phase disorder

Answer 33

• ealy morning awakening and inability to maintain wakefulness into the evening. Typically awake from 4am to 8pm

Question 34

which is associated with a ‘morning lark’; a ‘night owl’

Answer 34

morning lark: advanced sleep phase syndrome
night owl: delayed sleep phase syndrome

Question 35

what is ‘non-24’ sleep wake syndrome

Answer 35

individuals fail to entrain to the 24 hour day. It is frequent in blind individuals. May occasionally coincide to real day night, but becuase free-running clock is 24.5 hours they drift out of phase. They tend to have night time insomnia and day time sleepiness. Taking melatonin in 24 hour intervals tends to help

Question 36

what is the rate of adjustment to local time, or a ‘phase-shifted’ environment’ in those who fly across several time zones

Answer 36

one hour per day