Final answer:
External markers like light cues are critical for setting our 24-hour sleep rhythms, regulated by the circadian rhythms. Managing light exposure helps align our biological clock with the external environment, combating disruptions in sleep patterns.
Step-by-step explanation:
External markers known as light cues are essential in setting the body’s 24-hour sleep rhythms, which are part of our circadian rhythms. The regulation of these rhythms is critically managed by the suprachiasmatic nucleus (SCN) in the brain. The SCN aligns our biological clock with the external environment, with light being an especially significant cue. Exposure to natural light or bright light therapy can help reset our circadian clocks when they're disrupted due to jet lag or shift work, mitigating issues like insomnia and cognitive difficulties.
Melatonin, a hormone released in response to darkness, also plays a significant role in regulating sleep-wake cycles. The intricate interplay between circadian and homeostatic mechanisms is what dictates when we fall asleep and awake. Ensuring adequate exposure to light during awake periods and darkness during sleep can help maintain a healthy sleep schedule and avoid the adverse effects of sleep disorders.