Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 2 - Nervous > EEG, sleep & circadian rhythms > Flashcards

EEG, sleep & circadian rhythms Flashcards

1
Q

Define sleep

A

State of unconsciousness from which you can be aroused by stimuli (light, touch, sound)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Sleep occurs due to active inhibitory processes that originate where in the brain

A

Pons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Something below the level of the … must be actively sending … to the cortex

Evidence suggests this activity originates in the … of the brainstem

A

Mid-pons

Inhibitory impulses

Reticular formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Many neurons within the reticular formation are…

A

Serotonergic - produce serotonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Drugs that block serotonin formation inhibit or induce

A

Inhibit, so serotonin is critical to sleep induction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Serotonin is a precursor of what chemical

A

Melatonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Melatonin levels in the blood increase at morning or night

A

Night

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

By the morning, melatonin levels have rised or dropped

A

Dropped completely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the circadian rhythm

A

24-hour internal clock that is running in the background of your brain and cycles between sleepiness and alertness at regular intervals

It’s also known as your sleep/wake cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What part of the brain controls the circadian rhythm

A

Suprachiasmatic nucleus (SCN) in the hypothalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Suprachiasmatic nucleus (SCN) in the hypothalamus that controls the circadian rhythm sits above what structure in the brain

A

Optic chasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The circadian rhythm is entrained by external cues such as

A

Light/dark cycles but is not the entrainment as blind people have circadian rhythms too

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Activity in the SCN stimulates release of what chemical

A

Melatonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What gland produces melatonin

A

Pineal gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The hypothalamus releases what excitatory neurotransmitter that’s required for wakefulness (2 different names)

A

Orexin (aka hypocretin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Defective orexin signalling can cause what condition + describe a bit about it

A

Narcolepsy - suddenly fall asleep, enter directly into REM sleep with little warning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If the SCN is destroyed, then the circadian rhythm of sleep is lost, explain the likely reason for this

A

Loss of melatonin signalling and disruption of orexin signalling in the hypothalamus, (wakefulness normally being stimulated in the morning, when orexin level rises; sleep occurring at night when orexin levels fall).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Are orexin levels high in the morning or night

A

Morning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Name the 2 centres in the reticular formation

A

arousal centre + sleep centre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where is the reticular formation (regulates sleep and consciousness) located

A

Brainstem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do we have a self-sustaining cycle of wakefulness for many hours

A

Excitatory neurons in the Ascending Reticular Activating System (ARAS) stimulate excitatory pathways in the CNS & PNS
–> These further excitatory pathways then create a positive feedback cycle from the CNS and PNS back to the ARAS, boosting the ARAS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Towards the end of the day, excitatory neurons and signals become fatigued and fade. At this point, what takes over

A

Inhibitory peptide signals from the Sleep Centres in the Reticular Formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What investigation can assess level of consciousness in an awake person

A

EEG (Electroencephalogram)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does EEG record

A

wave patterns that reflect the electrical activity of the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What 2 things are interpreted from the wave patterns reflecting electrical activity on an EEG reading + describe what each of these are

A

Amplitude (wavelength): the size of the wave (ranges from 0-200 µV)

Frequency: number of waves per second (ranges from 1-50+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

In increasing consciousness,

  • frequency increases or decreases
  • amplitude increases or decreases
A

frequency increases

amplitude decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

In decreasing consciousness,

  • frequency increases or decreases
  • amplitude increases or decreases
A

frequency decreases

amplitude increases

28
Q

Describe the frequency and amplitude of an EEG of someone

  • under anaesthesia
  • in a seizure
A

Under anaesthesia:
High amplitude
Low frequency

In a seizure:
High frequency
Low amplitude

29
Q

4 main types of wave pattern of an EEG

A

1) Alpha
2) Beta
3) Theta
4) Delta

30
Q

In awake, relaxed state, what type of wave is seen on an EEG

A

Alpha waves

31
Q

When there’s less stimuli to the brain, neurons firing synchronously…

A

Summate and so increase their amplitude

32
Q

Describe the amplitude and frequency of an EEG of someone in the

  • awake, relaxed state
  • awake, alert state
A

Awake & relaxed:
High frequency
High amplitude

Awake & alert:
Even higher frequency
Low amplitude

33
Q

In awake, alert state, what type of wave is seen on an EEG

A

Beta waves

34
Q

Why is the amplitude low but the frequency high on an EEG of someone in the awake, ALERT state

A

So much electrical activity going on in the alert state that neurons fire asynchronously (out of sequence with each other) because so many stimuli –> desynchronised waves cancel each other out and don’t get recorded on EEG

35
Q

Are theta waves high or low frequency waves

A

Low

36
Q

When do you see theta waves on an EEG (3)

A

Common in children,

and during times of emotional stress and frustration in adults

Also occur during sleep

37
Q

Describe the frequency and amplitude of delta waves

A

Very low frequency

High amplitude

38
Q

When do you see delta waves on an EEG

A

Deep sleep

39
Q

How many stages of sleep

A

5

40
Q

Describe stage 1 sleep (S-sleep)

  • eye movements
  • light/deep
  • amplitude & frequency & wave type
A

Slow eye movements.
Light sleep so easily aroused.
High amplitude, low frequency theta waves

41
Q

Describe stage 2 sleep

  • eye movements
  • frequency of waves (2)
A

Eye movements stop
Frequency slows overall
- but there’s bursts of rapid waves called sleep spindles (clusters of high frequency waves)

42
Q

Describe stage 3 sleep

  • amplitude & frequency of waves
  • wave type
  • light/deep sleep
A

High amplitude, very slow (2Hz) delta waves interspersed with short episodes of faster waves

Spindle activity (bursts of high frequency waves) declines

DEEP SLEEP

43
Q

Describe stage 4 sleep

  • wave type
  • amplitude & frequency of waves
  • light/deep sleep
A

delta waves - high amplitude, low frequency

Deep sleep

44
Q

Describe stage 5 sleep

  • eye movements
  • frequency & amplitude
A

REM sleep - rapid eye movements

Fast, high frequency waves, low amplitude like those of the awake state

45
Q

What percentage of sleep is REM sleep

A

25%

46
Q

Slow wave sleep = what stages of sleep

A

Stages 1-4

47
Q

How long do the 5 stages take before the cycle repeats itself again

A

90 mins

48
Q

Time spent in REM sleep increases or decreases as the sleep cycle repeats

Time spent in deep sleep increases or decreases as the sleep cycle repeats

A

Increases

Decreases

49
Q

Most restful sleep is in what stage of sleep

A

4

50
Q

What stage is S-wave sleep (Deep slow wave sleep)

A

4

51
Q

Physiological characteristics of stage 4 sleep (3)

A

Decreased vascular tone (and therefore BP), respiratory and basal metabolic rate

52
Q

How long does REM sleep last

A

5-30 mins

53
Q

Why do only the eye muscles move during REM sleep but no other skeletal muscles

A

due to inhibitory projections from pons to spinal cord

54
Q

REM sleep is dependent on what neurotransmittory pathway

A

Cholinergic pathways

- anticholinesterases increase time spent in REM sleep because they boost ACh release

55
Q

What happens to HR, RR and brain metabolism in REM sleep (D-sleep)

A

Increases

56
Q

What wave type does the EEG pattern during REM sleep mimic

A

Beta waves associated with alert, awake state

57
Q

Is it easy or hard to arouse someone from REM sleep

A

Hard

58
Q

Sleep deprived people demonstrate what characteristics (4)

A
  1. Impairment of cognitive function (detected in early hours of sleep deprivation)
  2. Impairment of physical performance (detected in early hours of sleep deprivation)
  3. Sluggishness
  4. Irritability
59
Q

Sleep supports what physiological functions (5)

A
  1. Neuronal plasticity (needed for learning + memory)
  2. Learning and memory
  3. Cognition
  4. Clearance of waste products from CNS (rejuvenates neurons)
  5. Conservation of whole body energy
60
Q

Percentage of sleep that is REM sleep in full term babies

A

50%

61
Q

Define insomnia

A

chronic inability to obtain the necessary amount or quality of sleep to maintain adequate daytime behaviour

62
Q

2 types of insomnia

A

a) chronic, primary insomnia where there is usually no identifiable psychological or physical cause
b) temporary, secondary insomnia in response to pain, bereavement or other crisis.

63
Q

What drug used to be used to treat insomnia but not anymore + why (consequences)

A

Barbiturates

Chronic use increases time taken to fall asleep, decreases time spent in REM and stage 3 and 4 sleep, and increases no. of times awake during night

Dose required to treat insomnia too close to toxic dose

64
Q

Preferred insomnia treatment instead of barbiturates and benzodiazepines

A

Lifestyle habits that induce sleep

65
Q

What stage of the sleep cycle do night terrors occur

A

Deep, delta sleep (stage 4)

66
Q

Nightmares v night terrors

A

Nightmares are during REM sleep

Night terrors during stage 4 deep sleep, don’t really remember night terrors

67
Q

What is somnambulism + when does it occur

A

Sleep walking
Mainly in stage 4 sleep, never in REM
No recollection of it when waking up

Year 2 - Nervous (39 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions