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00:00Oh, I think I'm gonna lose that hot dog.
00:21Dear Tim and Moby, how come I get dizzy when I spin around?
00:27I'm Lyle.
00:30Let's just...
00:31I really don't think this is a good idea.
00:36Spinning around causes a disturbance in your inner ear, or labyrinth, where your sense
00:40of motion and balance are regulated.
00:43The labyrinth is two systems of fluid-filled passages that detect sound and motion.
00:49The motion-detecting passages are called the vestibular system.
00:54It's made up of five parts, the utricle, the saccule, and three semicircular canals.
01:01The utricle and saccule contain tiny crystals that rest on a thick layer of gel.
01:10When you accelerate or speed up in any direction, the crystals move along the gel, disturbing
01:15the hairs below.
01:17These cells are attached to nerves, which send out signals to the eyes and brain whenever
01:21the hairs move.
01:23That's how you know when you're moving.
01:26To locate our position in space, three semicircular canals monitor rotational movement.
01:32Those canals are arranged at right angles to each other, corresponding to the three
01:35dimensions of space.
01:39When you move your head in any direction, or turn your body around, it moves fluid inside
01:42the canals, stimulating hair cells that grow inside.
01:47Nerve signals from the hair cells go to the brain, the muscles that control your posture,
01:51and your eyes.
01:53Your eyes rely on these signals for information on where to look.
01:57They're constantly making small adjustments to where they focus, based on signals from
02:01the vestibular nerve.
02:03That's why spinning around messes up your vision.
02:05The fluid in your semicircular canals is moving, and your eyes are trying to follow that movement.
02:11Uh.
02:14The reason you might feel sick is because the signals from your ear conflict with the
02:22signals from the rest of your body.
02:24See, your sense of balance doesn't just come from your inner ear.
02:30It's really an interpretation of signals from all over your body.
02:34Your inner ear monitors motion and acceleration.
02:37Signals from your eyes tell you exactly where you are in space.
02:41Skin pressure receptors signal what parts of your body are touching the ground and which
02:45way is down.
02:47Muscle receptors signal which parts of your body are moving.
02:50And all of these signals are sent to the spinal cord and brain, where logical sense
02:54can be made of them.
02:57So when you stop spinning, the moving fluid in your inner ear tells your brain that you're
03:00still moving, but your eyes and muscles tell it that you're standing still.
03:09And that's when you start to feel sick.
03:12Uh, yeah, I guess I'm okay.
03:18On second thought, I'm just gonna hang here for a second.
03:22Ugh.