sleep Flashcards
What is sleep
State of unconsciousness from which an individual can be aroused by normal stimuli
What is a coma
State of unconciousness from which an individual cannot be aroused and does not respond to stimuli
Describe adenosine levels in the day
They build up in the day and once a threshold is reached, cause sleepiness
What is teh function of the suprachiasmatic nuclei
It demonstrates the 24 hour circadian rhythm and controls the release of melatonin from the pineal gland
Describe the Suprachiasmatic nuclei control of sleep
Inhibitory neurons in the Suprachiasmatic nuclei are stimulated by light which inhibit the pineal gland
Darkness removes the inhibiton and stimulates the pineal gland to secrete melatonin which increases the feelings of sleepiness
What is orexin
A excitatory neurotransmitter released from the hypothalamus which is required for wakefulness
What is the effect of SSRI on sleep and why
Serotonin selective reuptake inhibitors (SSRIs) increase sleep induction due to many of the neurons being serotonergic - serotin is a precursor to melatonin which induces sleepiness
What is an alpha wave pattern associated with on EEG
Relaxed awake state - high frequency and medium amplitude
What is a beta wave pattern associated with on EEG
alert awake state - very high fequency with low amplitude
What is theta wave pattern associated with on EEG
Earky sleep
What are delta waves associated with on EEG
Deep sleep
Why is the amplitude low and frequency high in EEG when you are in high alert
The brain is doing a lot of things which desynchronises the waves and makes them cancel each other out
What is stage 1 of sleep
Slow wave - non rem sleep - theta wave
Describe stage 2 of sleep
No eye movements - slow frequency but small bursts of rapid waves called sleep spindles
Describe stage 3 of the sleep cycle
- High amplitude but very slow delta waves with short bursts but the sleep spindle activity declines
Describe stage 4 of sleep
Only Delta waves
What is deep sleep
Stage 3 and 4 where it difficult to arouse the individual
What is REM sleep
Rapid eye movement - REM
Dreams occur
What happens after the initial deep sleep
There is a gradual awakening twards stage 1 but instead of stage 1, REM sleep is achieved which is a similar EEG state to awake
What is insomnia
Chronic inability to obtain necessary amount of slep to mantain adequate daytime behaviour
What is the difference between primary and secondary insomnia
Primary - Chronic and no identifiable cause
Secondary - temporary and in response to pain or another crisis
What is narcolepsy
Enter into REM sleep directly with little warning
