Final answer:
Circadian rhythms are biological cycles lasting about 24 hours that regulate patterns like sleep and wakefulness in humans, influenced by environmental light-dark cycles and are controlled by the brain's biological clock.
Step-by-step explanation:
The 24-hour cycles that include sleep-wake patterns in humans are known as circadian rhythms. These biological rhythms are internal processes that repeat around every 24 hours and are involved in many different physiological states, such as fluctuations in heart rate, body temperature, and blood pressure. Circadian rhythms are influenced by environmental cues, particularly the light-dark cycles, and are regulated by a biological clock located in the brain. Any disruption to these rhythms like those experienced during travel across time zones or shift work, can lead to sleep-related issues such as insomnia and decreased alertness. Moreover, these rhythms play a crucial role in the states of consciousness and are significant for processes such as learning and memory.
Sleep being a major component of circadian patterns, involves various stages, each characterized by specific brain wave patterns and physiological changes such as the release of growth hormones which are vital for physical maturation.