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 ?
Body temperature, which is involved in the regulation of the sleep/wake cycle, exhibits a circadian cycle, being two to three degrees Fahrenheit higher in the late afternoon/early evening than during sleep, when it is the lowest.
"At least 50 per cent of our metabolism is circadian, and 50 per cent of the metabolites in our body oscillate based on the circadian cycle. It makes sense that exercise would be one of the things that's affected.
Its uniqueness has also made it the first office building in Spain to implement a dynamic lighting system adapted to the circadian cycle of people.
Body temperature, which is involved in the regulation of the sleep/wake cycle, exhibits a circadian cycle, being 2-3 degrees Fahrenheit higher in the late afternoon/early evening than during sleep, when it is the lowest.
Melatonin, a hormone produced by the pineal gland and circulated throughout the body, operates on a circadian cycle to put the body into a relaxed state at night and a wakeful state toward morning.
Panda: Every gene in our genome has a circadian cycle. However, they don't cycle at the same times, and some cycle only in one organ.
Ironically, he pointed out that 'people who keep faith with their body clock cycle (known as the circadian cycle) by sleeping when they should, eat at the right time and work when they should live longer and are at a lesser risk of diseases.'
Participants lived in a facility under dim light conditions (10 lux measured from the forehead), ate three meals at set times, and followed a strict sleeping schedule: "To adjust the sleep-wake cycle among the subjects in reference to the circadian cycle, the times of retiring to bed and wake-up were fixed in such a way that the retirement time should be 4 h before the melatonin peak and sleep length should be 8 h." Blood samples, from an indwelling catheter in the forearm, were taken hourly during the first and last 24 hours and every two hours for the remainder of the study to examine the circadian peak phase of plasma melatonin.
The discrepancies between values that were calculated over a 24-h interval but with different starting times (which should be the same because they integrate over the full circadian cycle) were used to back-calculate the change in rate due to the captivity effect as
In nursing, I learned about the circadian cycle in our brains.
It is inherited in autosomal dominant mode, caused by circadian cycle irregularity as circadian clock genes are key players in its development.