What is vertigo?

Ginny - So, vertigo is this sensation of dizziness or spinning and most people will have experienced it if not any other time when you've had a few too many drinks. But some people get it quite regularly and it's all to do with your inner ear. So, inside your ear, you have three semi-circular canals, little sort of loopy things which are filled with fluid and they're all at 90 degrees to each other. That's how you know which way up your head is and which way it's moving because the fluid inside them moves, knocks into these little sensor hairs and that tells you how you're moving. When you spin around, the fluid in them starts to spin as well, but after you stop, it keeps spinning for a while and that's what makes you feel dizzy after you've been spinning around. But lots of things can make you feel like you're moving even when you aren't, which is what is happening in vertigo. There's some circumstances when it can be caused by little pieces of debris that have found their way into the inner ear and they confuse the signals that are being sent to the brain. That type of vertigo tends to happen only when your head is in a certain angle so the debris is hitting the little cells. It can also be linked with migraines. In which case, the problem is probably actually not in your ear, but in the nerves or in the brain itself. But scientists still don't really understand migraines. They're a bit of a mystery to us. Chris - Do you know what is weird though? Why the body has evolved to make the decision that when you get motion sickness or vertigo or something to throw up? What's the point of that?

Ginny - Well, vomiting is a sensible response if you've eaten something bad and it seems that dizziness can sometimes be an indicator of poison. So, I think that's how that evolved, that in some circumstances it was very useful to throw up because you'd eaten something bad. And actually, if you throw up a few more times than you need to, that's better than not throwing up when you should.