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Hearing And Balance movie

we'll be finding out about the origins of our senses; we're looking at the strange things that go on inside our ears. And how the tiny system of bony tubes in the inner ear evolved to carry out 2 separate senses, hearing and balance. We'll see what happens when you push your sense of balance right too the edge. We'll discover why acrobats fall down when the lights go out. And how astronauts learn to find their feet in a weight less world. And in the Florida swamps we'll be finding out about the origins of our sense of hearing. We'll uncover the sounds, which have the most powerful effects on us. Prepare yourself for an auditory assault course. And you'll discover why a loud rock concert can really blow your mind. The sounds we hear can have amazing effects on us. But recent research suggested that at certain frequencies loud sounds can vibrate the inner ear so much that the saculus gets shaken about as if we were free falling through the air, which would explain why loud sounds can trigger a pleasure rush through the brain, and make you feel like this.





 
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According to the theory the sound level needs to over 90 decibels. Loud enough to cause permanent damage, after a while. So will the crowd respond differently when the quo when they hit 90 decibels? 90 decibel's. When they're hit by a wall of sound like this the audience really gets carried away. This response to sound is really due to our sense of balance getting excited. So why our sense of balance is so closely connected to our sense of hearing? The answer goes back millions of years. In the Florida Everglades wild life expert Tim William's has spent years working with a Pre historic creature. The Alligator. Alligators were around before the dinosaurs. And they can tell us something about the origins of our own sense of hearing. Amazingly all modern reptiles, birds and mammals including us have ears based on the same ancient design. Once you live on land being able to hear sounds traveling through the air is crucial for survival. It helps parent's keep track of their young. It's also a good way to communicate. To warn off rivals, and most importantly to serenade a mate. In the breeding season the male alligators try to impress the females with deep bellowing. Just behind the eye there is a flap of skin covering the entrance to the ear, which is designed just like ours. When the first backbone animals emerged out of the water they already had all their other senses. Hearing in air was the last sense our ancestors developed. And it evolved as a spin off from their sense of balance. The tiny cochlea in the inner ear, which we use for sensing sound, is so closely linked to our balance organs, because the cochlea literally evolved as an off shoot from these older structures. In the second half of the program we're going to discover the secrets of our sense of balance. How we can do this? And even this. But then this makes us fall over. You fell really sick. Everything's just turning and turning about until you just fall to the ground. We'll find out why everything we do is an incredible challenge for our sense of balance. We'll discover how we keep track of how our bodies are moving even when the world is spinning around us. And exactly what it takes to bring it all crashing down. We humans are one of a very select club of creatures that get about on just their hind legs. There are only 2 kinds of animals that spend much of their life performing the tricky balancing act of walking on 2 feet. Us and some flightless birds. And neither of us has the ideal design for it. If you wanted to design an animal to balance on 2 legs you wouldn't necessarily end up with a human being or an ostrich. An ostrich has to work really hard not to topple over. A lot of its body weight is hanging over the front of its legs. Our body mass on the other hand is easier to handle. With a nice upright torso with all our weight directly over our legs. But our problem is a big heavy head at the top that can tip us over. And if walking on 2 legs aren't hard enough we go and make things even more difficult. What make life really tough for the human sense of balance are the crazy things we do with our bodies. Unlike any other animal we take pleasure in devising bizarre ways to test our sense of balance. And because we do all this it's a monumental challenge to keep track of where we are at all times. The world can be a pretty confusing place. Which way are we moving? Which way are we spinning? Which way is the right way up? Nun order to keep control you have to know how your body is moving through space. And when you're a stunt man like Marc Cass being aware of your own movements is vital to the job. It's really important for every stunt man to have good body co-ordination, know where they are in space. Other wise it could be a matter of life or death. So how do we sense which way our body is moving? For that basic information we rely on a set of special balance organs deep within the ear. This series of tubes and chambers no bigger than a pea monitors ever move made by our head. So when we take off, or skid to a halt, or go in to a spin. These movements are sensed within the inner ear. The tubes are full of fluid. Inside the tubes there are tufts of microscopic hair cells. When we move our heads the fluid move and the hair cells are bent. They send nerve signals to the brain. The tubes point in 3 different directions. And that's how we can sense movement in 3 dimensions. The balance sense in the ear tells us one other vital thing. Which way is up, and which way is down. You don't have to throw your body round that violently to test your balancing systems. Sometimes even standing upright can be a challenge. Getting around on 2 legs means we need to know what virtually every inch of the body is doing. So walking is an incredible challenge. Most of the time we're actually balancing on one foot. As we move almost every muscle in our body is involved in a furious battle to stop us from toppling over. So beside the balance organs in the ears we need sensors in our limbs and torso to let the brain know what the body is doing. Within a fraction of a second the brain sends out millions of signals to the muscles to make corrections that keep us balanced. But we're actually born without any ability to balance upright at all. We have to learn it through trial and error. And it takes years before the information between our limbs and our brain is processed fast enough so it all happens smoothly. Eventually walking becomes second nature. But it's such a complex operation that even the tiniest change can upset everything, like puberty. With our bodies growing so fast the nerve circuitry in our brains can't keep up with the changes to the body. The wrong signal was sent to the limbs and so for a while we're gawky and clumsy. When you realize just how difficult walking is it's no surprise that anything a little trickier takes a phenomenal amount of practice. It's not just our bodies we have to balance on our 2 legs. We also pick things up and carry them around. Doing this creates an even greater challenge for our sense of balance. The secret of our success is that we actually prepare ourselves before we do it Take a look at this. We've set up a simple test with a suitcase, some weights and a group of unsuspecting volunteers. First the suitcase is filled with around 12 kilos of weight. The volunteers are asked to pick up the suitcase and repeat the movement a few times. Then we take them out of the studio and ask them a question that has nothing to do with the experiment. So it's actually an observational test. Did you notice the color of the camera mans T-shirt? And while the volunteer is preoccupied we replace the weighted suitcase with an empty one. Ok. We'll go back to the studio. Ok. Because they don't know that a switch has been made they automatically balance them for a heavy case. So they falter but they don't fall over. Amazingly it takes just a fraction of a second for our sense of balance to detect what's wrong, adjust and keep us upright. With our top-heavy design moving around on 2 legs is a fantastic-balancing act. We use senses in the ear and through out the body to guide constant minute adjustments to thousands of muscles. But there's one other vital component to our sense of balance. We've come here to the circus centre in San Francisco to see it in action. Its awe inspiring what these acrobats can do. Some of these maneuvers take years of training. But we're about to see a stunt that will test even their sense of balance to the absolute limit They're going to perform one of the most difficult stunts in their repertoire, the human tower. It's going to take 4 people nerves of steel and a very strong foundation. It's teamwork. Everybody should work together. Back strong, legs strong. Keep stay there. Tight right. Stay tight, ok thank you good luck. As each person is added to the tower the problems multiply. If the tower is to stay standing, everyone has to stay as perfectly still and upright as possible. It's a hair-raising test for their sense of balance. Every detail supplied to the brain by the sensors in the inner ear and the limbs is crucial. But it's actually something else that's keeping Alex team standing. Neither the movement's sensors in their heads or their limbs can stop the really minute wobbles. For that they need their eyes. Their eyes tell them when they're swaying even slightly, because they can see the room's moving. So how well will they manage without their eyes? To find out they've agreed to build the tower again, but once they're up the lights are going to be turned off. The troop is going to attempt a tower of 3. Ok are you steady now? Now they're up the lights are going to go out and we'll switch to an infra red camera to see how they get on in the dark? Can these masters of balance keep the tower standing in complete darkness? Bad luck, it's so difficult to balance without the help of your eyes, that the team here reckon that no one has ever managed a tower of 4 in the dark. In fact we all rely on vision when it comes to keeping our balance. Standing on one leg is a bit tricky but with eyes open most of us can do it for quite a while. But what happens when you close your eyes? You quickly discover how much vision is keeping you upright. I'll loose balance a bit when I close my eyes. Why's that? Our sense of balance is an extraordinary combination of 3 separate sensory systems, in our ear, our limbs and our eyes. When they're all working together in harmony we can even stay upright in the most testing situations. But all of the time our balance system operates right at the limit. So even the slightest malfunction can send us crashing to the floor. When we move around the inner ear is normally superb at sensing the movement, but it's actually quite a delicate system these junior school children have volunteered to be thrown off balance. Games, which involve running about, and making quick turns are no problem. But change the movement slightly and it's a very different story. If you keep spinning round and round the fluid in your balance organ starts to move round and round too. The problem starts when we stop. Alright, first it you feel like you're moving around the earth. But when you stop the earth seems to move round without you. We may have stopped spinning but the fluid in the ear is still moving, so the brain thinks we're still turning round and round. You feel really sick. Everything's just turning and turning about until you just fall to the ground. But its not just children's games that throw us off balance, the over 18's have ways too. The world moves in a mysterious way if the signals from the balance centers in our brain are disrupted or delayed in any way. And there's a liquid that's very good at doing just that, alcohol. If we drink enough alcohol it starts to disrupt the nerve systems in the cerebellum. That's the brains balance centre. It's the part of the brain that co-ordinates all our movements in our muscles particularly in the legs. The alcohol level in the blood goes up and that starts to affect the cerebellum after a while, and that's when you start to stagger. Alcohol slows down the nerve signals from the brain to the legs, which destroys our sense of balance. So before the advent of the breathalyzer the test for drunk drivers was walking the line.
 
 
In the Florida swamps we'll be finding out about the origins of our sense of hearing
In the Florida swamps we'll be finding out about the origins of our sense of hearing
  Response to sound is really due to our sense of balance getting excited
Response to sound is really due to our sense of balance getting excited
 
But alcohol can have a second effect on our sense of balance. Drink enough of it an it even starts to mess with the balance organs within our inner ear, which creates a very unpleasant sensation. It's called the screaming Horizontals. It's when you put your head back, particularly if you have your eyes closed as well, but suddenly the room seems to take off. The world starts to lurch and it makes you feel quite sick and disorientated. The alcohol in the blood gets in to the inner ear affecting the tiny hair cells which sense movement. That tricks the brain in to thinking that movements are much more exaggerated than they are. So a small move feels like a complete 350-degree head spin. Ok a little bit dizzy to be perfectly honest. But apart from that not too bad. We rely on our separate balance systems to work together to keep us upright. We make life hard by throwing ourselves around like no other animal on the planet.
 
We're equipped with a fantastic system for hearing a phenomenal range of sounds
We're equipped with a fantastic system for hearing a phenomenal range of sounds
  The tiny choclea in the inner ear is so closely linked to our balance organs
The tiny choclea in the inner ear is so closely linked to our balance organs
 
Even our ability to walk upright is a massive achievement for our sense of balance. But we don't stop there. We're always testing how far we can go. And we push ourselves even further where no creature on earth was ever meant to go, by venturing in to the weightlessness of space. But if our sense of balance is so precarious, how on earth does anyone deal with weightlessness. We've come to Star city in Russia to find out. This Russian jet plane has been modified for a very special purpose. When its air born it will do something extraordinary. The conditions are so severe that you aren't allowed to fly unless your bodies in tip top condition. How is l? Like a cosmonaut thank you Now He's passed the medical this volunteer is about to experience his first trip aboard the vomit comet. Every child wants to experience what its like to be an astronaut floating in space. But the vomit comet can produce extreme motion sickness - Some people end up in hospital on a drip because they lose so much fluid vomiting. To create zero gravity the pilot has to execute an enormous ark at 25,000 feet.
 
Scientists think its because in our minds it feels like we're hearing our own heart beating faster
Scientists think its because in our minds it feels like we're hearing our own heart beating faster
  We take pleasure in devising bizarre ways to test our sense of balance
We take pleasure in devising bizarre ways to test our sense of balance
 
First the plane makes a steep climb at full throttle. Then the powers cut and the plane arks over into a dive. And everything on board becomes weightless. The steep climbs and nosedives are so ferocious that according to some cosmonauts a trip on the vomit comet is tougher on our sense of balance than space itself. There it goes there's nothing on earth that can prepare you for this. Then plane is plummeting through the sky. But inside the cabin it seems as though they're just floating serenely. With no gravity the balance sensors in the inner ear aren't working. And with no windows its hard to get any clues to which way is up or down. Yet amazingly after a few goes most of these people who have never flown the vomit comet before are starting to enjoy them. The secret is to decide what's up and what's down and to completely ignore the confused signals from the sensors in your inner ear. It's extraordinary how quickly our bodies can adapt to a strange New World where non-of the normal rules apply. This must be the ultimate triumph of the senses. To survive in an environment that sense of balance was never designed for.