Please enable JavaScript.

Coggle requires JavaScript to display documents.

Why we sleep? - Coggle Diagram

- - - - -controlled by the suprachiasmatic nucleus (20,000 cells), samples light information carried by optic nerves. Also controls core body temperature fluctuations.
        -Breaking olympic records, timing of births and death tied to time of day
        -De Mairan 1729 - Mimosa Pudica plant generates its own circadian rhythm even in total darkness
        -Kelitman 1938 - six weeks in mammoth cave in Kentucky. Bed legs in buckets of water to prevent creepy crawlies. Rhythm is 15 minutes longer than the 24 hour day, hence circa- (around/approximate). Reset by sunlight, food, exercise or social interaction.
      - Chronotypes
        
        -night owls and morning larks have different rhythms
        -humans evolved to live in tribes. Greater survival rates if the group is not collectively vulnerable. Night owls serve as security guards so to speak.
      - Melatonin
        
        -released from pineal gland, used to communicate repeating signal of day and night.
        -does not participate in generating sleep itself. It's merely the timing official of a race. So, melatonin is not a powerful sleeping aid. With the exception of jet lag.
        -many melatonin pills are of inferior quality.
      - Jet lag
        
        -the SN can only adjust one hour each day to a different time zone. Melatonin would be helpful in this case.
        -harder to acclimate when flying eastward: 1.need to fall asleep faster 2.rhythm is naturally longer than 24hrs. Easier to stretch a day than shrink it
        -cabin crews, pilots, shift workers all suffer brain size shrinkage in areas related to memory. Including higher rates of diabetes and cancer.
    - - -adenosine buildup creates sleep pressure
        -caffeine (second most traded commodity after oil), works by blocking adenosine receptors. Removed by cytochrome p450 1A2. Removal rate dependent on genetics and age.
        -NASA 1980 spider web experiment - caffeine webs look the most messy
        -separate system from circadian rhythm. After pulling an all-nighter, may still feel alert at 11am because melatonin is at its nadir at that time, despite the sleep pressure.