Tsirkadiaanstsüklid

Tsirkadiaanstsüklid are biological rhythms that occur with a period of approximately 24 hours. These endogenous rhythms are found in most living organisms, including plants, animals, and even bacteria. The term "circadian" comes from the Latin words "circa" meaning approximately and "dies" meaning day.

These internal biological clocks are synchronized with the external environment, primarily through light and darkness cycles. Light detected by specialized photoreceptors triggers signals that reset the circadian clock, ensuring it remains aligned with the 24-hour day. This synchronization is crucial for optimizing physiological processes and behaviors to the day-night cycle.

In humans, circadian rhythms regulate a wide range of functions, including sleep-wake cycles, hormone release, body temperature, and metabolism. Disruptions to these rhythms, such as those caused by shift work, jet lag, or prolonged exposure to artificial light at night, can have significant negative health consequences. These can include sleep disorders, mood disturbances, metabolic issues, and an increased risk of chronic diseases.

The molecular mechanisms underlying circadian rhythms involve complex feedback loops of gene expression and protein activity. These "clock genes" and their protein products interact to generate the rhythmic oscillations that drive the circadian system. While the core machinery is conserved across many species, there are variations in the specific genes and their regulation. Research into circadian rhythms continues to uncover their intricate role in health and disease, opening avenues for therapeutic interventions.