system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:What happens when I lose consciousness?

So I was thinking about this while falling asleep last night. What happens exactly? I know you could drift into 'what exactly is consciousness territory' here. But what's my brain doing/doing less of and why does it mean I lose consciousness altogether?

Also as a bonus question - whats the difference between being knocked out and falling asleep in this respect?
gpt
Your brain is compartmentalized.  Different bits of it handle different tasks.  When you lose consciousness, the part that handles being awake slows down to a crawl while some other parts are still partying like it's 1999.

When you get knocked out, it is because the base of your brain gets jarred badly enough to smack against the inside of your skull.  The parts of your brain controlling motor function and consciousness reside there, and they're taken offline for a bit.  Consciousness is usually regained and motor control returns after a brief respite.  Sleep is handled chemically.  Your brain literally shuts off your ability to move in order to prevent injury while your consciousness is offline.