How sleep works is you become semi unconscious, the difference between someone in a coma or fainting is that you can wake up a sleeping person if the stimulus is strong enough(smells, noise, bright lights,water ect.) during this period your body relaxes and you brain produces slow delta waves and you enter into REM sleep at different points which is the period in which you dream. All animals sleep and some even dream. Some birds dream and all mammals dream.
"If you attach an electroencephalograph to a person's head, you can record the person's brainwave activity. An awake and relaxed person generates alpha waves, which are consistent oscillations at about 10 cycles per second. An alert person generates beta waves, which are about twice as fast.
During sleep, two slower patterns called theta waves and delta waves take over. Theta waves have oscillations in the range of 3.5 to 7 cycles per second, and delta waves have oscillations of less than 3.5 cycles per second. As a person falls asleep and sleep deepens, the brainwave patterns slow down. The slower the brainwave patterns, the deeper the sleep -- a person deep in delta wave sleep is hardest to wake up.
At several points during the night, something unexpected happens -- rapid eye movement (REM) sleep occurs. Most people experience three to five intervals of REM sleep per night, and brainwaves during this period speed up to awake levels. If you ever watch a person or a dog experiencing REM sleep, you will see their eyes flickering back and forth rapidly. In many dogs and some people, arms, legs and facial muscles will twitch during REM sleep. Periods of sleep other than REM sleep are known as NREM (non-REM) sleep.
REM sleep is when you dream. If you wake up a person during REM sleep, the person can vividly recall dreams. If you wake up a person during NREM sleep, generally the person will not be dreaming.
You must have both REM and NREM sleep to get a good night's sleep. A normal person will spend about 25 percent of the night in REM sleep, and the rest in NREM. A REM session -- a dream -- lasts five to 30 minutes. "
If you take medication, especially sleep medication it can seriously mess with REM sleep, lowering the quality and the chances of actively dreaming, and remembering them.
When we don't get enough sleep we are going to suffer the consequences, the first day may not be so bad suffering irritability, slowness feeling burnt out or a boost of adrenaline that makes you feel like a kid with to much sugar.Though as day with n sleep arrives concentration becomes difficult, you slow down even more and mistakes in simple actions increase, the feeling of detachment to the world allows you to reside in la la land for indefinate periods of time. After the third day in a court f law you can declare insanity as a person will start to hallucinate and clear thinking becomes absolute, if wakefulness continues a person will totally lose there grip on reality. Rats in an experiment forced to stay awake have died...which is terrible fr the rats and an awful experiment, though it is a sever warning how lack of sleep can affect the body.
Many of the same problems can occur from losing sleep each night, there is no need to not sleep for three nights to lose concentration power and take a vacation to la la land.During sleep chemicals are secreted that are to boost our immune system and in children the ones that help them grow. During sleep our muscles are in repair mode as well as tissues and the replacement of aging or dead cells.Our brains spend this time archiving the days thoughts memories and information, hence your mom telling you to get a good nights sleep before a test after studying. The third thing your body does in save energy so you only have to eat 3 meals a day rather then 5 or 6 think of your grocery bill. All these reasons together make up enough reasons to believe that 8-9 hours a day sounds good.Grow adults need 8-9 hours a sleep a day while children need 12-10 and seniors on 6-7. Though each person knows what they need to feel their best.
Brain, Marshall. "How Sleep Works." 01 April 2000. HowStuffWorks.com.