circadian rhythm

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circadian rhythm

n.
A daily rhythmic activity cycle, based on 24-hour intervals, that is exhibited by many organisms.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

cir·ca·di·an rhythm

(sər-kā′dē-ən)
A daily cycle of biological activity based on a 24-hour period and influenced by regular variations in the environment, such as the alternation of night and day.
Did You Know? Why do you sometimes wake up on time even if your alarm clock doesn't ring? How do nocturnal animals know when it is time to wake up? It's because you—and most other animals—have a kind of internal clock that controls the cycle of the day's biological activities, such as sleeping and waking. These daily biological activities are known as circadian rhythms because they are influenced by the regular intervals of light and dark in each 24-hour day. While the process underlying circadian rhythm is not completely understood, it is mainly controlled by the release of hormones. The brain regulates the amount of hormone released in response to the information it gets from light-sensitive cells in the eye, called photoreceptors. Circadian rhythms can be disrupted by changes in this daily schedule. For example, biologists have observed that birds exposed to artificial light for a long time sometimes build nests in the fall instead of the spring. In humans who travel long distances by air, the local time of day no longer matches the body's internal clock, causing a condition known as jet lag.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

circadian rhythm

The regular recurrence of life activities in 24-hour cycles.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.circadian rhythm - a daily cycle of activity observed in many living organisms
biological time - the time of various biological processes
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
Translations

cir·ca·di·an rhythm

n. ritmo circadiano, ref. a variaciones rítmicas biológicas en un ciclo de 24 horas.
English-Spanish Medical Dictionary © Farlex 2012
References in periodicals archive ?
Effect of chronic ethanol ingestion on biochemical circadian rhythms in Wistar rats.
Daily or circadian rhythms include the sleep-wake cycle, and rhythms in hormone release are controlled by a molecular clock that is present in every cell of the human body.
Circadian rhythms regulate a variety of physiological and metabolic processes in diverse organisms.
Women who have stronger circadian rhythms may experience lower risk for dementia, a study suggests.
Wirz-Justice, who has led numerous investigative studies in the field and lectured on the role of circadian rhythms in affective disorders at the congress.
No one thought these findings might hold any relevance for humans, whose circadian rhythms were then widely believed to be relatively insensitive to light.
(1,2) Such characteristics are controlled by circadian rhythms under the command of the organism's circadian pacemaker, also referred to as the "biological clock" The word circadian is taken from the Latin circa dies, meaning "around a day" and, in this instance, refers to the endogenous flee-running clock within the hypothalamus.
Release date- 01082019 - Our circadian rhythms, the innate 24-hour cycles that tell our bodies when to wake up, when to eat and when to fall asleep, will be explored in a new exhibition at the Glucksman, UCC.
Shift workers, for example, disrupt their natural circadian rhythms and have a higher risk of heart disease as a result (as well as obesity, diabetes, and stroke).
The World Health Organisation put shift work on its list of potential carcinogens because of the impact upon circadian rhythms - the 24-hour internal clock that cycles between sleepiness and alertness at regular intervals.
Sleep disorder expert Dr Guy Leschziner, a consultant neurologist at Guy's and St Thomas' Hospitals in London, said: "We know that however circadian rhythms are disrupted, it is not good for your health.
Researchers have now identified insulin as a primary signal that helps communicate the timing of meals to the cellular clocks across our body, and in doing so strengthen the circadian rhythm. The team's experiments in cultured cells, replicated in mice, show that insulin, a hormone released when we eat, adjusts circadian rhythms in many different cells and tissues individually, by stimulating the production of a protein called 'period', an essential cog within every cell's circadian clock.