and other biological activities are associated with this cycle and the body makes significant changes, in response to it, through out the day. This sheerly- balanced, natural cycle is derived from our ancestors. Besides controlling our sleeping and feeding patterns, this daily rhythm controls migration, mating and reproduction in several forms of life.
The word 'Circadian' ('circa' means '24 hrs' and 'dian' means 'day') was coined by Franz Halberg. When the circadian rhythm is synchronized with nature our bodies respond to the glorious sunlight and secretes cortisol, serotonin, hormones and neurotransmitters that are required for normal functioning. Temperature and blood pressure are also elevated, as the body gears to face the challenges of a new day. At dusk, the body responds to the sinking sun, and the ensuing darkness helps to stimulate the production of melatonin.
Temperature and pressure decreases, and the body prepares for rest and sleep.
The circadian rhythm is controlled by a group of cells, situated in the hypothalamus of the brain, called Supra Chiasmatic Nucleus
(SCN), otherwise referred to as the 'Biological Clock'.
Sunlight reaches the SCN through the photoreceptors in the retina of the eyes. The signal is transmitted to the pineal gland in the brain to stimulate melatonin production. The concentration of melatonin ebbs during the day and elevates by night.
When our biological clock is out of synchrony with nature, in other words, when it malfunctions due to poor signal receptivity, it gives rise to Circadian Rhythm Disorders
(CRD). When these disorders affects sleep, it is called Circadian Rhythm Sleep Disorders
(CRSD). Poor receptivity can occur due to environment, travel, illness, working shifts or awry life style. Melatonin production is delayed or is premature and there is a shift in the sleep cycle. This results in sleepiness when a persPage: 1 2 3 Related medicine news :1
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