Biological rhythm

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A biological rhythm is a repeated or approximately repeated change in a biological process. Rhythms occur at many timescales and may be generated internally, driven by environmental cycles, or produced by interactions between internal clocks and external cues.

Circadian rhythms have periods close to 24 hours. Infradian rhythms last longer than a day and include annual reproductive or migration cycles and the menstrual cycle. Ultradian rhythms repeat more than once per day, including sleep-stage cycles and pulsatile hormone release.

Other categories include tidal rhythms, lunar rhythms, and rhythms in gene expression, metabolism, neural activity, and behaviour. Rhythms are described using period, frequency, phase, amplitude, peak, trough, and entrainment.

Biological rhythms allow organisms to anticipate regular environmental changes and coordinate processes efficiently. Their molecular bases often involve feedback loops, oscillating gene expression, interacting biochemical reactions, and communication among cells and organs.

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• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Biological_rhythm