The biological clockwork
Have you ever noticed how beautifully your body mechanism is regulated and your daily life is scheduled? Well, everyone may not agree saying that they don't follow a specific routine for their daily life. Imagine, yesterday you woke up at 5 or 6 AM. If you do this consistently, no alarm is required to wake you at that practiced time. There is an alarm, virtually though, inside your body. In fact, there exists a biological clock, or more accurately clocks, in every living being, controlled and integrated by the brain where the master clock resides. The master clock, which is composed of SCN (Suprachiasmatic nuclei) cells, a group of nerve cells located in the hypothalamus region of the brain, makes a symphony, so that they are in synchronization, with the other clocks throughout the body and organs like in the esophagus, lungs, liver, pancreas, spleen, thymus, and the skin and thus creates and maintains perfect harmony.
Life on earth evolved in the presence of a daily cycle of day and night and thus the living organisms present today have obtained an internal rhythm that dictates different behaviors and body mechanisms at different times of a day. Controlled by the biological clock, humans, like most animals and plants, maintain certain biological rhythms known as circadian rhythms which work on a 24 hour time scale and to maintain this 24 hour day-night cycle, the biological clock needs regular environmental time cues or zeitgebers, like sunrise and sunset and temperature fluctuations during day and night, among which light cues are the most important to maintain a normal rhythm which can turn genes on or off that control the biological clock.
In 1971, Ronald J. Konopka and Seymour Benzer first identified a genetic component of the biological clock using the fruit fly Drosophila melanogaster as a model system. Molecular genetic studies indicate that the 24 hour period arises from a system of interconnected feedback loops that control the transcription, the process of making RNA from genes, of a small number of "clock genes". In the body, the SCN cells, receiving neural cues, stimulate the pineal gland of the brain, which then release melatonin hormone and this hormone then carries the signal to the rest of the body in time with the biological clock. The detailed and precise study of biological clock is important because if the clock is disturbed, different types of illnesses may occur in humans like sleep disorders, bipolar disorder which is a category of mood disorders, jetlag, shift work disorders which affect people who frequently rotate shifts or work at night. According to a 2010 study carried out by the Light Research Center, disruption of the biological rhythms may affect performance and well-being in humans. Dr. Sara Mednick, Assistant Professor at the University of California, San Diego and author of "Take a Nap! Change Your Life" tells that, "If you look at the statistics right after we change our clock just for one hour, you see an increase in car accidents, an increase in heart attacks", which clearly shows the importance of a rhythmic biological clock, and harmony of the body with the environment. A number of studies have concluded that a short period of sleep during the day, a siesta, can decrease stress and improve productivity.
Although there are several treatment options for the disorders resulting from the disrupted biological rhythms like behavior therapy, light therapy and medications such as melatonin, a naturally occurring sleep aid, these are not enough to restore the rhythms to their normal state. Therefore, more research to understand the genes related to the biological clock can be useful to get a complete understanding of the biological rhythms which, in response to the environment, help us to eat, sleep and behave in a regular fashion.
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