As I read on, I learned that our bodies biologically have rhythm which influences our functioning and synchronizes with the 24 hour day and night cycle called the circadian rhythm. Our body temperature raises during the morning, peaks at mid-day and progressively drops in late afternoon until we fall asleep again. I learned Light can also effect or circadian rhythm because as light approaches it triggers protein cells in the retinas that sent signals to the suprachiasmatic nucleus (SCN) in the hypothalamus which regulates body temperature. The SCN also causes the pineal to decrease the production of a sleep hormone called melatonin in the morning and increase its produntion in the evening.
As I continued the chapter progressed to the different stages of sleep and the biological rhythm of or sleep. Researchers use electroencephalograph (EEG) to observe the brain waves and patters that occur while you sleep. About every 90 minutes we go through different stages of sleep. While you are awake and relaxed the EEG detects alpha waves but while you sleep the EEG detects different waves for each different stage. One interesting fact was that we never recall the moment we fall sleep and as I read I tried to recall moments when I went to sleep the night before, indeed I could not remember the point at which my mind had fallen asleep; I could only recall getting into bed, the dream I had and waking up in the morning.
While we sleep we undergo and interesting thing, rapid eye movement sleep (REM sleep). At this point we are dreaming and our brain fires signals to may sensations at a time. We dream less than