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circadian rhythm |
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circadian rhythm: see rhythm, biological rhythm, biological, cyclic pattern of physiological changes or changes in activity in living organisms, most often synchronized with daily, monthly, or annual cyclical changes in the environment. ..... Click the link for more information. . circadian rhythmInherent cycle of approximately 24 hours in length that appears to control or initiate various biological processes, including sleep, wakefulness, and digestive and hormonal activity. The natural signal for the circadian pattern is the change from darkness to light. The controlling mechanism for these cyclic processes within the body is thought to be the hypothalamus. Any change in the circadian cycle (such as jet lag and other conditions associated with travel) requires a certain period for readjustment. circadian rhythm [sər′kād·ē·ən ′rith·əm] (physiology) A self-sustained cycle of physiological changes that occurs over an approximately 24-hour cycle, generally synchronized to light-dark cycles in an organism's environment. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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and gorillas, the researchers found that while the human clock is 3 percent slower than the chimp's, it is 11 percent slower than the gorilla's. The study of the human clock, which resides in a tiny collection of brain cells called the suprachiasmatic nucleus, has become a pressing issue. However, he hints that the use of bright lights may someday serve to reset the human clock in the elderly--whose biological clocks tend to "speed up" with age -- or in physicians and other workers who must toil through the night. |
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