how do we stay awake

Question 1

2 processes determining tiredness

Answer 1

sleep homeostat

circadian clock

Question 2

REM sleep

Answer 2

unconscious
active cerebral cortex
paralysis of skeletal muscles
dreams present
saccadic (quick, simultaneous) eye movements

Question 3

nREM sleep

Answer 3

unconscious
reduced cortical activity
reduced muscle tone

Question 4

assessing sleep

Answer 4

EOG: electroencephalogram - brain wave activity
EEG: electrooculogram - measure eye movements
EMG: electromyogram - detect muscle tone

Question 5

homeostatic sleep drive

Answer 5

• sleep pressure

builds up w/ time spent awake

Question 6

circadian sleep drive

Answer 6

increases at night
helps to keep you asleep (cause homeostatic sleep drive will decrease once you sleep - need circadian so that you dont wake up)

Question 7

adenosine

Answer 7

builds up with increased awake time
ATP -> ADP -> AMP -> adenosine. builds up when high energy (ATP) is used
reflects neuronal energy stores and neuronal activity = high adenosine signifies that u just did some high energy activity

Question 8

awake/ arousal hormones

Answer 8

pons -> thalamus -> cerebral cortex
- acetylcholine

upper brainstem/ post hypothalamus -> cerebral cortex

• noradrenaline
• serotonin
• dopamine
• histamine

Question 9

VLPO

Answer 9

ventrolateral preoptic nucleus
contains GABA - only increases during REM and nREM. does not activate during wakefulness
inhibits wake promoting areas in hypothalamus and brainstem

Question 10

orexin neurons

Answer 10

stabilising sleep-wake transitions
activate components of the arousal system -> promotes wakefulness

loss of orexin neurons: narcolepsy (chronic sleep disorder - overwhelming daytime drowsiness and sudden attacks of sleep)

Question 11

melatonin hormone

Answer 11

highest during middle of the night, decreases when waking up

Question 12

cortisol hormone

Answer 12

low during the night
rises sharply before waking up
prepares for daytime activity and metabolic demands

Question 13

SCN (suprachiasmatic nucleus) lesion

Answer 13

causes loss of behavioral and physiologic circadian rhythms

SCN needed for generation/expression of circadian rhythms. self-sustaining

Question 14

factors affecting sleep

Answer 14

OSA
PLMD/ restless sleep syndrome - need to move around so cannot sleep properly
DSPD (delayed sleep phase disorder) - shifted body clock

Question 15

obstructive sleep apnea (OSA)

Answer 15

excessive daytime sleepiness caused by repeated obstruction of airway during sleep

caused by: congenitally narrowed airway/ obesity (-> increased soft tissue in retropharyngeal space)

Question 16

good sleep habits

Answer 16

regular bedtimes
avoid caffeine/ exercising before bedtime
avoid watching TV/phone before bedtime
environment: off lights, off TV, quiet, comfort