vuorokausisäätely

Vuorokausisäätely, also known as circadian regulation, refers to the biological processes that control the approximately 24-hour cycle of physiological and behavioral changes in living organisms. This internal biological clock, or circadian rhythm, influences a wide range of functions including sleep-wake cycles, hormone release, body temperature, and metabolism. The primary master clock in most mammals, including humans, is located in the suprachiasmatic nucleus (SCN) of the hypothalamus in the brain.

The SCN receives direct input from the eyes, allowing it to synchronize the body's internal clock with the external light-dark cycle. Light is the most potent environmental cue, or zeitgeber, for resetting the circadian rhythm. When light hits the retina, signals are sent to the SCN, which then orchestrates the timing of various bodily functions. Disruptions to this natural rhythm, such as those caused by shift work, jet lag, or excessive artificial light exposure at night, can lead to sleep disorders, impaired cognitive function, and an increased risk of various health problems, including metabolic syndrome, cardiovascular disease, and certain cancers.

The molecular mechanisms underlying circadian rhythms involve a complex network of genes and proteins that interact in a feedback loop, oscillating over a roughly 24-hour period. These core clock genes are present in nearly all cells of the body, allowing for peripheral clocks in organs like the liver and heart to be synchronized with the master clock in the SCN. Maintaining a regular sleep-wake schedule and adequate exposure to natural light are crucial for promoting healthy circadian regulation and overall well-being.