Module 34 - Sleep Flashcards Preview

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Flashcards in Module 34 - Sleep Deck (55)
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1
Q

What is the behavioral definition of sleep?

A

Defined behaviourally: normal suspension of consciousness.

2
Q

What is the electro-physiological definition of sleep?

A
  • Defined electro-physiologically: Specific brain wave criteria (a series of precisely controlled physiological states)
    • Governed by brainstem nuclei
3
Q

How much does sleep consume our lives?

A

Sleep consumes ⅓ of our lives

4
Q

Is sleep well understood?

A

Most of the details about sleep are poorly understood but its clinical importance is obvious
I.e. acute/chronic lack of sleep can interfere with daily activities

5
Q

Why do we sleep? Animals are particularly vulnerable while sleeping… must have a considerable advantage.

A
  • Replace glycogen levels
  • Colder at night (efficient energy expenditure)
  • Humans and other animals are dependants on vision/light
  • Memory consolidation
6
Q

True or false: the adverse effects of lack of sleep are well documented.

A

TRUE

7
Q

What happens when you don’t sleep?

A

Sleep deprivation can lead to reduced cognitive function (problem solving and memory) and concentration.

8
Q

What are some of the specific brain regions that are known to be particularly vulnerable to sleep deprivation?

A

…“specific brain regions involved with certain neurocognitive domains, including executive attention, working memory, and higher cognitive functions, are known to be particularly vulnerable to sleep deprivation.”

9
Q

Explain the example of medical residents and how it is proof to what happens when you don’t sleep.

A
  • Residents are more likely to have a motor vehicle crash or “near miss” after a night of on-call duty, or after a shift lasting 24 hours or longer.
  • Sleep-deprived residents also have more attention lapses, experience more adverse events, and make more diagnostic errors while on duty overnight.
10
Q

What is sleep debt?

A

Sleep debt or sleep deficit is the cumulative effect of not getting enough sleep. A large sleep debt may lead to mental or physical fatigue. There are two kinds of sleep debt: the results of partial sleep deprivation and total sleep deprivation.

11
Q

Does sleep debt need to be repaid very quickly?

A

YES, right away

12
Q

Is fatigue a cause more vehicle accidents?

A

Yes

13
Q

How is sleep across the lifespan?

A
  • Most adults sleep for ~8 hours
  • Infants and teenagers sleep more
  • Older adults sleepless
14
Q

Why do OT’s and PT’s care about sleep?

A
  • OT = “Restful and adequate sleep provides the foundation for optimal occupational performance, participation, and engagement in daily life, a concept that is historically consistent with the development of occupational therapy.”
  • PT = “Participation in an exercise training program has moderately positive effects on sleep quality in middle-aged and older adults. Physical exercise could be an alternative or complementary approach to existing therapies for sleep problems.”
15
Q

What are circadian (once per day) rhythms?

A
  • Most people sleep for ~ 8 hours a day, which is regulated by our circadian rhythm = to sleep once a day.
  • Circadian rhythms are physical, mental, and behavioral changes that follow a daily cycle. They respond primarily to light and darkness in an organism’s environment. Sleeping at night and being awake during the day is an example of a light-related circadian rhythm.
16
Q

True or false: Most people sleep for ~ 7 hours a day.

A

False: Most people sleep for ~ 8 hours a day.

17
Q

You could potentially start sleeping at any point in the 24-hour cycle… So, how do we know when to sleep?

A
  • Photoentrain: (synchronize) physiological processes with the day-night cycle
  • “Biological clock” must be able to detect decreases in light levels as night approaches
    • Both of these aspects = maintain daily rhythms in spite of the variable amount of daylight & darkness in different seasons + different locations on the planet.
18
Q

What is the suprachiasmatic nucleus (SCN)

A
  • “Master Clock”
  • Specialized cells in ganglion layer of the retina contain melanopsin
  • These cells convey information about environmental light levels information to the suprachiasmatic nucleus - located in the hypothalamus
  • The SCN ultimately activates the pineal gland, modulating the production of melatonin.
  • Melatonin in the bloodstream modulates SCN activity re: sleep/wake cycles
  • Less light = more melatonin
19
Q

What type of cells conveys information about environmental light levels information to the suprachiasmatic nucleus?

A

Specialized cells in ganglion layer of the retina contain melanopsin

20
Q

Where is the suprachiasmatic nucleus located?

A

In the hypothalamus

21
Q

The SCN ultimately activates the _______________, modulating the production of ______________.

A

The SCN ultimately activates the pineal gland, modulating the production of melatonin.

22
Q

What modulates SCN activity re: sleep/wake cycles?

A

Melatonin in the bloodstream

23
Q

True or false: More light = more melatonin

A

False → Less light = more melatonin

24
Q

What is the history of the stages of sleep?

A
  • For many years, “we” though sleep was uniform (i.e. the same from start to finish)
  • Passive physiology for physical and mental restoration
  • In the mid-1950’s we learned that sleep has stages
  • EEG recordings showed at least four stages of sleep
25
Q

What are the stages of (non-REM) sleep? (don’t need to know more detail than what is on the image)

A

IMAGE

26
Q

What are some characteristics of stage I of sleep?

A

Reaction to stimuli from the outside world diminish
“Had just fallen asleep or had been in the process of doing so.”
Stray thoughts and short dreams

27
Q

What are some characteristics of stage II of sleep?

A

Unlikely to react to light or a noise, unless it is extremely bright or loud.
Nearly 50 % of the total sleep time spent in this stage.

28
Q

What are some characteristics of stage III of sleep?

A
  • Truly deep sleep.
  • Little response to external stimuli unless very strong or have personal meaning (e.g. fire alarm, your name, your baby crying)
29
Q

What are some characteristics of stage IV of sleep?

A
  • The deepest stage of non-REM sleep.
  • Lowest neuronal activity.
  • Sleepwalking and night terrors.
  • Most of the body’s repair work
  • Muscle tone, heart rate, breathing, metabolic rate, body temperature and blood pressure are all decreasing through the stages and are at the lowest in stage IV.
30
Q

Nearly 50 % of the total sleep time is spent in this stage. Which sleep stage is it?

A

Stage II

31
Q

Which stage is the deepest stage of non-REM sleep and has the lowest neuronal activity?

A

Stage IV

32
Q

Which stage is the “truly deep sleep”?

A

Stage III

33
Q

Muscle tone, heart rate, breathing, metabolic rate, body temperature, and blood pressure are all decreasing through the stages and are at the lowest in stage _______?????

A

Muscle tone, heart rate, breathing, metabolic rate, body temperature, and blood pressure are all decreasing through the stages and are at the lowest in stage IV.

34
Q

What are the stages of cyclical sleep?

A
  • ~60 minutes of non-REM sleep = stage I - IV
  • Followed by ~10 minutes of REM sleep
  • Then the cycle repeats
  • Over the course of a night, roughly four additional periods of REM sleep occur - each longer than the last.
35
Q

Over the course of a night, roughly ______ additional periods of REM sleep occur - each longer than the last.

A

Over the course of a night, roughly four additional periods of REM sleep occur - each longer than the last.

36
Q

How much time are you in a non-REM sleep during the sleep cycle?

A

~60 minutes

37
Q

How much time are you in REM sleep during the sleep cycle?

A

~10 minutes
BUT as the cycle repeats, we get longer REM sleep periods, each longer than the last.

38
Q

What are some of the characteristics of REM sleep?

A
  • Relatively high neuronal activity
    • Almost as much as during wakefulness
      • The physiological state is in sharp contrast with sleep stages 1-4
  • Positive effects on immune function
    • Lower proportion of REM sleep in older adults(?) → decrease in immune function
  • Memory consolidation
  • High prevalence of dreaming
39
Q

True or false: REM sleep neuronal activity is almost as much as during wakefulness.

A

True! Relatively high neuronal activity = Almost as much as during wakefulness
The physiological state is in sharp contrast with sleep stages 1-4

40
Q

In which sleep stage is there a high prevalence of dreaming?

A

REM sleep

41
Q

In which sleep stage is there memory consolidation?

A

REM sleep

42
Q

How does a lower proportion of REM sleep in older adults affect their immune function?

A
  • A decrease in immune function
  • Therefore, we know that REM sleep has positive effects on immune function
43
Q

If REM sleep is almost like we are awake, then why don’t we act out our dreams?

A

We don’t act out our dreams:
The reason we dont is because the sensory input and motor output are inhibited during sleep

44
Q

What is our sensory input and motor output inhibited by, during sleep?

A

It is done through dopamine

45
Q

What happens when we have dopamine antagonists

A

There is less dreaming

46
Q

What happens when we have dopamine agonists

A

There are more intense dreams

47
Q

What are the theories of why do humans sleep?

A
  • Restorative theories
    • Replenish brain glycogen levels
    • Tissue growth and repair
  • Energy conservation theory
    • Metabolic demands are lower during sleep
  • Brain plasticity theory
    • Memory consolidation
    • Infant brain development → perhaps the reason why infants sleep so much is that their brain is developing at such a high rate
  • “Impaired sleep has been associated with Alzheimer’s disease. Studies suggest that sleep plays a role in clearing beta-amyloid out of the brain.”
48
Q

What is the restorative theory of why we sleep?

A

Replenish brain glycogen levels
Tissue growth and repair

49
Q

What is the energy conservation theory of why we sleep?

A

Metabolic demands are lower during sleep

50
Q

What is the brain plasticity theory of why we sleep?

A
  • Memory consolidation
  • Infant brain development → perhaps the reason why infants sleep so much is that their brain is developing at such a high rate
51
Q

Is impaired sleep associated with Alzheimer’s disease?

A

“Impaired sleep has been associated with Alzheimer’s disease. Studies suggest that sleep plays a role in clearing beta-amyloid out of the brain.”
In Alzheimer’s disease, there are these beta-amyloid plaques that build up, so these are typically cleared out with sleep

52
Q

What is the connection between sleep and memory?

A
  • Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during slow-wave sleep and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories.
  • Our brain plays things over when we are sleeping, and REM sleep may stabilize recently transformed memories.
53
Q

What is the connection between sleep and health outcomes - particularly cardiovascular outcomes?

A

Both short and long duration of sleep is predictors, or markers, of cardiovascular outcomes. [coronary heart disease, stroke, cardiovascular disease]

54
Q

True or false: Too little OR too much sleep has negative cardiovascular outcomes

A

True

55
Q

True or false: Increased sleep is correlated with decreased mood

A

False: Decreased sleep is correlated with decreased mood