sleep----------

Question 1

why do we sleep?

Answer 1

To conserve energy during times when it would be inefficient or dangerous to be out looking for food
To give the body and brain a chance to rest and synthesize new proteins
Repair damage sustained during the day
Strengthen memories formed during the day

Question 2

what makes us want to sleep?

Answer 2

Endogenous Rhythms (Zeitgeber): “generated from within”
Regular cycles of activity and inactivity that keep constant length in the absence of environmental cues
Environmental cues may determine the start/stop time of endogenous rhythms
Circadian rhythm: repeats about once every 24 hrs.

Question 3

what are TIM and PER

Answer 3

proteins that build up all day and reach peak in the evening at sleepiness
SCN stops making Tim/Per at night, so levels fall à wakefulness

Question 4

SCN- what is it
where is it?
whats it do?

Answer 4

• suprachiasmatic nucleus
• in hypothalamus
• SCN neurons maintain a circadian rhythm even if separated from the brain. axons in the optic nerve bring light/dark info to the SCN to entrain circadian.

Question 5

melanopsin- what is it

whats it do

Answer 5

photopigment in ganglian cells

works independent of rods and cones to bring light info into SCN

Question 6

what is melatonin

Answer 6

it makes you sleepy

Question 7

what happens in the pineal gland?

Answer 7

some SCN neurons send axons here.

when PER and TIM levels are high, SCN stimulates the penal gland to release MELATONIN.

Question 8

acetylcholine

Answer 8

Released throughout cerebral cortex

Increases arousal, promotes wakefulness

Question 9

norepinephrine

Answer 9

involved in arousal

Question 10

histamine

Answer 10

indicated in wakefulness

Anti-histamines block H1 receptors in the brain leading to drowsiness

Question 11

orexin

Answer 11

Neuropeptide released by the hypothalamus
Stimulates ACh neurons
Necessary for extended periods of wakefulness

Question 12

adenosine

Answer 12

By-product of normal neuronal activity
Builds up during the day; high levels make you sleepy
Caffeine blocks adenosine receptors (antagonist)

Question 13

GABA

Answer 13

Released throughout cerebral cortex and thalamus
Decreases overall brain activity; promotes sleep

(many sleep aids on the market are GABA agonists)

Question 14

structure of sleep

Answer 14

• 4 stages + REM
• Cycle through stages about 4-5 times/night
• More REM close to waking in AM

Question 15

stages 1

Answer 15

• Irregular, low amplitude EEG waves

- Hypnic myoclonia: abrupt jerking of muscles, usually preceeded by feeling of falling

Question 16

stage 2

Answer 16

Sleep spindles and K-complexes

Question 17

stage 3 & 4

slow wave sleep

Answer 17

=Higher amplitude, lower frequency EEG waves
=Activity is synchronized across multiple brain areas
=Deep, restorative sleep

Question 18

REM (PARADOXICAL SLEEP)

Answer 18

• Irregular, high frequency, low amplitude EEG waves (similar to stage 1)
• Vivid, memorable dreams
• Postural muscles are paralyzed

Question 19

Sleep Disorders: Narcolepsy

Answer 19

Attacks of sleepiness during day
Cataplexy: sudden muscle weakness, esp. when excited or stressed
Paralysis during non-REM sleep
Vivid hallucinations while awake or just falling asleep
Very little stage 3 & 4 sleep
Some cases are caused by lack of orexin

Question 20

REM behavior disorder

Answer 20

Pons normally inhibits the descending motor pathways  paralysis during REM
Damage to pons  vigorous motor activity during REM
Punching, kicking, running, jumping
Different from sleepwalking, which is common and happens during stage 3 & 4 sleep
Most common in middle-aged men and associated with Parkinson’s disease.

Question 21

TIM & PER- how are they made?

Answer 21

when you wake up, you make TIM & PER for about 12 hours, then you stop making it. the levels rise during day and reach peak when you should get sleepy. as you sleep, you no longer produce so levels fall.
they are lowest before you wake up.

Question 22

TIM & PER where are they made?

Answer 22

in the SCN- TIM & PER send axons to pineal glad. when TIM & PER are at peak, the pineal glad releases melatonin, which makes you sleepy

Question 23

pineal gland is involved with

Answer 23

sleep

Question 24

what’s melatonin do?

Answer 24

it makes you sleepy. it is released when TIM and PER peak.

Taking melatonin (drug) in the afternoon phase-advances the SCN clock (sleepy earlier)

Rozerem stimulates melatonin receptors to help you fall asleep earlier, but must be taken about 3 hours before desired sleep time. also not as effective when TIM & PER levels are too low

Melatonin also helps to prevent east-bound jet lag

Question 25

4 neurotransmitters that promote awareness

Answer 25

acetylocholine
noeprinephrine
histamine
orexin
adenosine

Question 26

acetylocholine

Answer 26

helps maintain awareness

Question 27

norpinephrine

Answer 27

promotes arousal

Question 28

histamine

Answer 28

arousal and wakefulness

Question 29

orexin

Answer 29

long term- increased ACH release

Question 30

adenosine

Answer 30

involved with sleepiness, builds up during the day like TIM & PER, but throughout the brain. caffeine blocks receptors, which helps you stay awake.

Question 31

malanopsin

Answer 31

send signals to SCN
ganglion cells have photopigment- different from rods/cones. they respond to lights, but don’t give you visuals. they assist in TIM & PER

Question 32

antihistamines

Answer 32

make you tired. block histamines

Question 33

GABA-

Answer 33

Decreases activity of all neurons. released all over brain during sleep.

Question 34

what happens during stage 2 of sleep?

Answer 34

sleep spindle- short bursts

K-complex spikes- trying to synchronize neurons.

Question 35

what happens during stages 3-4 of sleep?

Answer 35

its a deep sleep. youre less likely to wake with noise.

it looks like the neurons are doing the wave.

Question 36

REM SLEEP

Answer 36

when you have the most vivid dreams.

Question 37

REM disorder

Answer 37

violent movement due to damage of brain stem.