Sleep

Sleep

 it’s a type of behavior and stage of consciousness 

 two factors that distinguish sleep from other non-wake states

Responsiveness - the responsiveness from stimuli outside and inside the body is reduced when sleeping, however it is not absent  

Reversible - the sleep state is reversible but with qualifications

Homeostatic process

 determined of the prior amount of sleep and and waking, the amount of sleep and waking is directly related to daytime sleepiness

Circadian process

organizes the sleep and waking over a 24 hour cycle, this process relies heavily on the light and dark cycle under the 24 hours

Ultradian process

controls the alteration between NREM and REM the two sleep stages, the rhythm is a 90 to 120 minute cycle of NREM and REM, this repeats 3 to 6 times a night

Zeit-geber

time givers, our inner clock (circadian rhythm) must be synced every day by outer signals. Examples of these is: light/darkness, regular food intake, social habits/interaction

Glymphatic system

 this system cleans the brain cerebrospinal fluid throughout the brain, this only happens when you sleep. CBF clear out the brain from proteins such as amyloid-beta and tau which are linked to Alzheimer's

Lymphatic system

 is the network consisting of lymph vessels, lymph glands, lymph organs that transports lymph throughout the body to maintain fluid balance and help the immune system

Main sleep hormone

Melatonin - stimulated by darkness and is the main sleep hormone, regulates circadian rhythm and tells the body when it’s time to sleep.

Restorative

This hypothesis suggests that sleep is crucial for restoring and repairing the body and brain. During sleep, the body can repair tissues, build muscle, and synthesize proteins. The brain also clears out metabolic waste that builds up during waking hours.

Cleansing

The idea here is that sleep facilitates the removal of waste products from the brain. During sleep, the brain's glymphatic system becomes more active, helping to clear out toxins, such as beta-amyloid, which are associated with neurodegenerative diseases like Alzheimer's

 Memory Consolidation

This hypothesis proposes that sleep plays a critical role in consolidating memories. During sleep, especially during deep sleep and REM sleep, the brain processes and strengthens memories from the day, transferring information from short-term memory to long-term storage.

Insomnia

 difficulty maintaining or falling asleep, non-restorative sleep  that gets worse each day that follows with effect in daytime being easily irritated, sleepiness during the day, having low energy

Primary insomnia

the individual has associated sleep and its environment with cognitive arousal, this is not related to any other disease or disorder,  this is why it's important to only sleep in your bed and not do anything else 

Secondary insomnia

when insomnia arises in connection to a medical or psychiatric disorder, for example 80 % of depressed patients have insomnia

Polysomnography

 is used while evaluating an individual's sleeping disorder, it works by measuring multiple physiological functions while sleeping 

• EEG - brain activity to decide sleeping stages 

• EOG - eye-movement, important for REM-sleep 

• EMG - muscle activity, jaw and bone 

• Breathing - airflow, chest and abdomen movement 

• EKG - heart function