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Paper Topic:


Circadian Rhythms

Ever wonder why people sleep at night and work during the day ? Why do people feel sleepy when darkness falls ? These questions can be answered by understanding the concept of circadian rhythms

From the Latin word circa (meaning around , and diem (meaning day , circadian rhythms are a cycle of the physiological processes of living things , such as human beings , plants , and animals ( HYPERLINK "http /www .wikipedia .com " www .wikipedia .com . This cycle is controlled by what people know as our biological clock ' which normally operates on a 24-hour cycle . This

clock is actually called the suprachiasmatic nucleus or SCN , which is located in the hypothalamus (located in the brain ) directly above the area where the optic nerves cross . When light enters our eyes and reaches the retina , the optic nerves will then send signals to our brain through the SCN . These signals reach different parts of the brain , which includes light-responding receptors called the pineal glands (www healthlink .mcw .edu . At night , when only a little light enters the retina , the pineal gland produces more melatonin , making people drowsy Conversely , too much light shuts off the production of melatonin . This explains why people are normally asleep at night and awake during the day . However , external factors can also affect our circadian rhythms such as noise when we are asleep or intake of alcohol that makes people sleepy

We must note that not all people have normal circadian rhythms . This is because our body clock does not only respond to light and dark cues , but to external activities of a person as well . This phenomenon is called the free-running circadian rhythm (FRCR ) or the non-24 hour sleep /wake cycle . FRCR is a dis that makes a person 's sleep time to occur later and later , with the peak of alertness also adjusting during the day ( HYPERLINK "http /www .wikipedia .com " www .wikipedia .com and www .apollohealth .com . Most often , blind people are the ones who experience FRCR due to little or no amount of light that enters their retinas . However , people who work at night and sleep at day , as well as people who work in shifting schedules are also vulnerable to this dis

Basically , the circadian rhythm is our sleep /wake cycle that is determined by the body clock situated in the brain . And because the brain in the central control system of the entire body , it is normal that it gets tired and needs rest . After about 18 hours without sleep , a person 's reaction time begins to slow and slower down until the brain cannot process at all . And the longer we stay awake , the more our brain 's condition deteriorates (Gorman , 2004 , www .time .com . This is the very reason why people need sleep . To put it lightly , the brain is the human body 's battery to enable us to perform our activities , and sleep is the re-charger when the battery is out of energy

But how much do we really need to sleep ? Researches...

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