Sleep: Dreams, Nightmares, and MemoriesA proverbial quote often attributed to Benjamin Franklin and his Poor Richard's Almanac states: "time lost is never found." Time is a precious thing, and with only 24 hours in a day, it seems like there's never enough daylight. As precious as time is, we don't use the entire 24 hours. We spend a third of our lives sleeping. This means that if the average person lives to be 80, they will spend about 27 years sleeping! So why do we spend so much time unconscious, oblivious to the world? Sleep is a mystery, but research has shown that it is necessary for our health. Stages of Sleep Before we can understand sleep and its stages, we must first understand how the brain functions during sleep. Neurotransmitters are chemicals in our brain that send different neurons to control whether we are asleep or awake. “Neurons in the brainstem…produce neurotransmitters…that keep parts of the brain active while we are awake.” We have other neurons located lower in the brain that “turn off” the signals that keep us awake when we fall asleep. "Research also suggests that a chemical called adenosine builds up in our blood while we are awake and causes drowsiness. This chemical gradually breaks down while we sleep" (NINDS). Even while we sleep, the brain still works as hard as during the day. There are five stages of sleep: stages 1, 2, 3, 4 and REM sleep. Each stage has distinct characteristics, and science suggests that each stage appears to serve a distinct purpose. "Not knowing why humans spend a third of their lives unconscious hasn't stopped scientists from describing five different stages of sleep from bra recordings.... ... middle of paper .... ..E First. Internet. March 24, 2014. Levin, Ross and Nielsen, Tore. Nightmares, bad dreams and emotional dysregulation. Current directions in psychological science. 2009. Internet. April 2, 2014.McLeod, Saul. Sigmond Freud. Simply psychology. 2013. Internet. March 25, 2014. National Institute of Neurological Disorders and Stroke. Brain Basics: Understanding Sleep. December 5, 2013. Web. March 31, 2014.Saey, Tina Hesman. The why of sleep. Science News. October 24, 2009: 16. MasterFILE Premier. Internet. March 25, 2014 Study reveals sleep is vital for memory. Brigham and Women's Hospital, Harvard Medical School, and University of Pennsylvania. July 10, 2006. Web. April 2, 2014. Uma Devi P, Murugan S, Senapathy J G. Sleep strengthens memories. Journal of Clinical and Diagnostic Research. February 2010. Internet. March 26, 2014. Winson, Jonathan. The meaning of dreams. Scientific American. 1990. the web. April 2. 2014.