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Endogenous Circadian Rhythm

Meaning

The Endogenous Circadian Rhythm is the self-sustained, internal biological oscillation in physiological and behavioral processes that operates on a cycle of approximately 24 hours, even in the absence of external time cues. This rhythm is fundamental to nearly all life forms, governing critical functions such as the sleep-wake cycle, hormone secretion, core body temperature, and metabolic rate. It is generated by the master pacemaker, the suprachiasmatic nucleus (SCN), and its intrinsic period, though close to 24 hours, must be regularly synchronized, or entrained, by external signals like light to maintain alignment with the solar day. The integrity of this internal clock is vital for health and disease prevention.