SCN, or Suprachiasmatic Nucleus, is a small region located in the brain's hypothalamus. It plays a crucial role in regulating the body's internal clock, known as the circadian rhythm. This rhythm influences various biological processes, including sleep-wake cycles, hormone release, and body temperature. The SCN receives information about light from the eyes, helping it synchronize the body's functions with the day-night cycle. When light levels change, the SCN adjusts the production of melatonin, a hormone that promotes sleep. This coordination is essential for maintaining overall health and well-being.