The suprachiasmatic nucleus (SCN) is like the master clock of your brain, nestled in the hypothalamus. This tiny, but mighty, group of cells plays the pivotal role of syncing your body’s rhythms with the 24-hour cycle of day and night. It’s the reason you feel jet-lagged after a flight across time zones—the SCN is adjusting to a new rhythm. Essentially, it’s your body’s natural timekeeper, orchestrating your sleep-wake cycle, hormone release, and other key bodily functions.