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.

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.

circadian rhythm

The regular recurrence of life activities in 24-hour cycles.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.circadian rhythm - a daily cycle of activity observed in many living organisms
biological time - the time of various biological processes
Translations

cir·ca·di·an rhythm

n. ritmo circadiano, ref. a variaciones rítmicas biológicas en un ciclo de 24 horas.
References in periodicals archive ?
It stimulates the photosensitive retinal ganglion cells, stimulates pupillary reflex and controls the circadian cycle.
2) He proposed that exposure to light at night (LAN) disrupted melatonin production and the circadian cycle.
This realisation has fuelled a "sleep hygiene" movement, whose proponents point out that bright lights before bedtime and spending the whole day in a dimly lit office can dampen the natural circadian cycle, leaving people in a continual mental twilight - dozy in the morning, and too alert to fall asleep promptly at night.
Bet you've noticed how the 24-hour cycle of your circadian cycle works--that's the pattern of wakefulness and sleepiness you naturally have.
Research has shown fatigue impairs work performance mainly due to sleep loss, extended wakefulness, working and sleeping at suboptimal times in the circadian cycle, and workload.
Disrupting just the amplitude--or strength--component of the circadian cycle, Evans adds, was enough to alter hormone levels, including those that wake us up in the morning.
Even an incandescent lamp can disrupt the circadian cycle if it is too bright.
Indicator of control parameters of training and circadian cycle.
Dr Mike Haydon, who performed much of the research and is now at the University of York, added that the accumulation of sugar within the plant provides a kind of feedback for the circadian cycle in plants- a bit like resetting a stopwatch.
The body clocks of humans and other land-dwelling organisms are synchronised by the light and dark cycles - the circadian cycle.
As this new world emerges, some people decide to continue to live by the lengthening circadian cycle, and they are known as "real timers".
The molecular circadian cycle is initiated when the transcriptional activators Clock and Bmal1 (Bunger et al.