the sleep cycle

Question 1

what are 3 triggers for sleep?

Answer 1

Diurnal patterning is key
Arousal levels
Learnt behaviour

Question 2

3 main regions control arousal

Answer 2

Brainstem reticular formation

Thalamus – Reticular nuclei

ARAS (Ascending reticular activating system)

Question 3

what is included in the brainstem reticular formation?

Answer 3

Spans the three brainstem regions

Complicated network of fibres

Heterogeneous matrix

Complex but not Random

Some defined nuclei

Question 4

what is the thalamus ?

Answer 4

Multinucleate region in the diencephalon

Question 5

the thalamus has nuclei involved in 2 features what are they ?

Answer 5

1.motar
2.sensation

Question 6

how many hemispheres are in the thalamus?

Answer 6

Two hemispheres linked by the intra-thalamic adhesion.

Question 7

what is the reticular nucleus involved in?

Answer 7

controlling flow through the thalamus.

Question 8

what is ARAS(ascending reticular activating system)?

Answer 8

Fibres from RF acting on thalamus and cortex

Question 9

what 5 functions is ARAS involved in?

Answer 9

Arousal
Motivation
Integration
Motor control
Autonomic control

Question 10

what are 2 key transmitters controlling in arousal?

Answer 10

1.Histamine
2.acetylcholine

Question 11

what do orexin and melatonin regulate?

Answer 11

sleep cycle pattern

Question 12

orexin

Answer 12

hypothalamus

Question 13

melatonin

Answer 13

pineal gland

Question 14

what 4 disorders is included are orexin and melatonin impacted by?

Answer 14

1.jet-lag
2.narcolepsy
3.mood disorder
4.memory.

Question 15

what are the 3 things in waking?

Answer 15

Metabolically demanding
Sympathetic activity
Muscle tone and power

Question 16

what are the 3 things in non-rem sleep?

Answer 16

Metabolism low
Parasympathetic activity
Muscle tension and movement decrease

Question 17

what are the 4 things in rapid eye movement (REM) sleep?

Answer 17

Paradoxical Sleep’
Metabolically demanding
Sympathetic activity
Atonia

Question 18

what happens to the levels in wake state

Answer 18

noradrenaline, 5HT and histamine levels increase

Question 19

what does the reticular system activate?

Answer 19

ACh innervation of reticular nuclei of thalamus. Ach ↑

Question 20

what happens to GABA cells(non rem-sleep cells) in slow-wave sleep?

Answer 20

in hypothalamus act on tuberomammillary bodies

Question 21

when gaba cells act on tuberomammilary bodies what happens to the histamine levels?

Answer 21

decrease

Question 22

when histamine levels decreases in gaba cells what happens to the act input to the thalamus

Answer 22

it decreases and so does the sensory input which is in the resting state

Question 23

what happens to the levels of NA, 5HT in rem state

Answer 23

decrease
Loss of NA and 5HT reduces inhibition of ACh

Question 24

in rem sleep what happens to the input to the thalamus?

Answer 24

increases and Cortical activity increases, but motor outflow is kept low by activation of glycine pathways

Question 25

what are the 3 stages of rem sleep?

Answer 25

Waking Non-REM (NREM or N) REM

Question 26

what are the 3 stages of NREM?

Answer 26

Stage N1: drowsy Stage N2: light sleep Stage N3: deepest - Slow-Wave Sleep (SWS)

Question 27

Dyssomina -sleep disorder what are the 4 main groups

Answer 27

Insomnias - lack of sleep Parasomnias - around sleep Sleep apnoea - breathing stopping Narcolepsy - spontaneous sleep onset

Question 28

Insomnias

Answer 28

Inability to fall asleep or remain asleep for sufficient time

Question 29

what are 5 causes of insomnia?

Answer 29

Lifestyle (learnt behaviour) Circadian rhythm disruption (jet-lag) Emotional Disturbances Ageing Children

Question 30

what are the 2 treatments of insomnia?

Answer 30

Behavioural therapy Pharmacological (short term only) – hypnotics*

Question 31

what is parasomnia caused by?

Answer 31

around sleep partial arousal from different stages of sleep Little/no recall of episode – nightmares/RBD dreams are recalled

Question 32

what are 2 forms of sleep apnoea?

Answer 32

1.central 2.obstructive

Question 33

what are risk factors for sleep apnoea?

Answer 33

Neurological Weight/Hypertension Adenoid/tonsil size/polyps Smoking/Drinking

Question 34

what are the treatments of sleep apnoea?

Answer 34

Pharmacological agents generally ineffective Weight/BP management Orthodontic intervention Continuous Positive Airway Pressure (CPAP) Surgery*

Question 35

what is narcolepsy characterised by?

Answer 35

Excessive daytime sleepiness Sudden onset sleep Cataplexy - usually emotionally triggered Sleep paralysis/RLS Hallucinations – hypnagogic/hypnapompic Disrupted nocturnal sleep patterns Automaton-like behaviour

Question 36

what are the causes of narcolepsy?

Answer 36

Orexin Genetic

Question 37

what is the treatment of narcolepsy?

Answer 37

Stimulants* and routine