Circadian Rhythms Essay Example | Topics and Well Written Essays - 1000 words

Circadian Rhythms - Essay Example Circadian rhythm takes place in wide variety of organisms apart from humans and are controlled by environmental and internal factors. Temperature and light are the common environmental factors. The circadian cycle is controlled by suprachiasmatic nucleus located in hypothalamus region of brain that influences the sleep-wake cycle by receiving signals from retina of eye about light and dark. The photoreceptor cells in retina transmit signals on light activation and deactivation via neurons of retinohypothalamic tract to the SCN, which are further transmitted to pineal gland via the superior cervical ganglion.  Circadian rhythm takes place in wide variety of organisms apart from humans and are controlled by environmental and internal factors. Temperature and light are the common environmental factors. The circadian cycle is controlled by suprachiasmatic nucleus located in hypothalamus region of brain that influences the sleep-wake cycle by receiving signals from retina of eye about l ight and dark. The photoreceptor cells in retina transmit signals on light activation and deactivation via neurons of retinohypothalamic tract to the SCN, which are further transmitted to pineal gland via the superior cervical ganglion.   The superior cervical ganglion releases noradrenaline into pineal cells during dark, which is followed by transformation of serotonin into melatonin. The SCN leads to the release of more melatonin hormone from pineal gland when the light levels are low that in-turn influences the brainstem mechanisms.