Science Common Sense

857 - How does the brain regulate our sleep-wake cycles?

Our brain regulates our sleep-wake cycles using a special process called our "body clock." It's like an internal timer that tells our body when to be awake and when to sleep.

There's a tiny part in our brain called the suprachiasmatic nucleus (SCN) that controls our body clock. It sends signals to the rest of our body to make us feel tired or awake.

Here's how it works:

• During the day, our brain gets signals from the sun's light through our eyes.
• The SCN gets these signals and says, "Hey, it's daytime. Be awake."
• At night, the light goes away, and the SCN says, "Okay, it's nighttime. Time to sleep."
• Our brain then releases special chemicals called hormones that make us feel tired or awake.

One of these hormones is called melatonin. It's like a sleep-inducing medicine that our brain produces naturally.

So, our brain's body clock uses light and darkness to control our sleep-wake cycles. That's why we usually feel more tired at night and more awake during the day.