PS101 Lecture Notes - Lecture 7: 2Degrees, Insomnia, Ecological Niche
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Michael Matthews October 5, 2011
Circa Dies- circadian rhythms. Can influence many factors. (How you write an exam)
Through a 24 hours period, your body temperature will vary between 2 degrees. When our body
temperature is at its max, we are at our max.
During the evening, the immune system recedes slightly.
The control of this rhythm is found in the hypothalamus in the supercliasmatic nuclei. Secretes melatonin,
makes us want to go to sleep. Melatonin levels peak during the hours of 1 and 3.
Most Canadians ignorant about their sleep.
Micro sleeps are 10-20 second sleeps that can happen at the wheel. When the mind is tired the memory is
not as effective and clear, judgement is skewed.
Between 1-6 am it is normal for us to feel tired.
Circadian rhythm phase advance (jet lag) flying from west to east. Phase delay, is flying east to west. Most
do not like the phase advance because it leads to more accidents. (7% increase in accidents)
Death’s counterfeit the sleep god and death god were identical.
When you are allowed to sleep as much as you need, you average 10.3 hours a day.
Stages of sleep:
First few minutes is the first stage, when you have the sensation of falling and jerking around. Stage two
last about 3o minutes, sleep spindles at 10 cycles per second.. Stage three is a transitional stage from 2 to 4.
Stage 4 is a very deep sleep, 1 spindle per second). Generally at stage 4 is when problems like bed wetting
happens. After about an hour of stage 4, you move up through the stages and you enter the most interesting
state which is called “dream sleep” R.E.M. (rapid eye movements) sleep.
Called paradoxical sleep because they look like they are very relaxed, yet the brain is very fired up and
aroused. This cycle continues to repeat itself every 90 minutes.
Why do we sleep? It is restorative would seem fairly common sense. The body heals itself from the daily
wear and tear. It reconstitutes the brain, as it reorganizes itself. It also reconsolidates memories. During
sleep we have metabolic waste that is removed. Ecological niche.
The animals that are at the top of the food chain get much more sleep than those at the bottom. If our need
is eight hours of sleep, than it implies that it takes that group 16 hours to gather food.
Sleep has profound implications for growth. Our pituitary glands inspire growth as we sleep. Newborns
spend about 2/3 of their day sleeping.
Studies do now confirm that there are firm connections between good sleeping and memory. When people
learn a new skill, they don’t perform better until a good sleep. Sleep is more important than intellectual
power in terms performance.
An 8 hour sleep, the first 2 hours of sleep is that brain chemicals plummet at information flows outside of
the hippocampus into the cortex. The next four hours the brain is very active as the brain involves itself in
an internal dialogue as it sorts where the information is stored. In the last two hours, brain chemistry
changes again, and the cortex going into an active dreaming stage, where is goes through the learning
again, to help integrate these new materials into their memory banks. REM sleep is essential for integrating
big pieces of information in the long term.
Success mostly depends on how well you sleep in order to remember information.
The brain also decides what materials are important and not important. Retrieval of information is much
easier as well.
Try and get a regular sleep schedule. If you nap, be consistent about them. Be careful with alcohol and
caffeine. A drink may help you sleep better, but you may wake you up earlier. Caffeine is a stimulant and
can disrupt your sleep. A warm glass of milk may help you to go to sleep. Eating heavily late at night, your
system will be working throughout the night which will keep your digestive system up all night.
You should not do exercise right before you go to bed.