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No matter what you do, your ears are always working. They are constantly detecting, deciphering and analysing sounds and communicating them to the brain. In a comparatively tiny area of our body the ear is performing many highly technical and intricate functions. Consider just a few of them:
(1) The human ear can cope with an incredible range of sound. Your ear can, in fact, cope with a 10,000,000,000,000 fold difference in loudness. That’s a range of 130 decibels.
(2) The ear can pick out and focus in on a particular sound or conversation in a roomful of noise.
(3) The human ear can detect a difference of just two degrees in the direction of a sound source.
(4) The ear is able to recognise at least 400,000 different sounds, matching them up against those stored in the memory banks.
What we see of the ear is just the outer part of a very complex structure. There are three distinct portions to the ear: the outer ear containing the fleshy skin and the canal that leads to the inner ear, the middle ear containing the three smallest bones in the human body – the malleus, incus and stapes (commonly called the hammer, anvil and stirrup) and the inner ear, made up of a cluster of three semi circular canals and the snail shaped cochlea. Let's take a look at them one at a time . . .
The Outer Ear
The outer ear collects sound waves in the air and channels them to the inner parts of the ear. The outer ear along with it’s canal has been shown to enhance sounds within a certain frequency range. That range just happens to be the same range that most of the characteristics of human speech sounds fall into. This allows the sounds to be boosted to twice their original intensity.
The Middle Ear
The middle ear transforms the acoustical vibration of the sound wave into mechanical vibration and passes it onto the inner ear. The three tiny bones of the middle ear act as a lever to bridge the eardrum with the oval window. Incoming forces are magnified by about 30 %. This increased force allows the fluid in the cochlea of the inner ear to be activated.
The Inner Ear
The semi-circular canals in the inner ear allow us to maintain balance and coordination. The cochlea, which is a bundle of three fluid filled canals coiled up in a spiral, is set in motion by the stirrup in the middle ear. Moving in and out it sets up hydraulic pressure in the fluid. As these waves travel to and from the apex of the spirals, they cause the walls separating the canals to undulate. Along one of these walls is a sensitive organ called the Corti. It is made up of many thousands of sensory hair cells. From here thousands of nerve fibers carry information about the frequency, intensity and timbre of all these sounds to the brain, where the sensation of hearing occurs.
Scientists cannot fully explain just how the signals are transmitted to the brain. They do know that the signals sent by all the hair cells are about the same in duration and strength. This has led them to believe that it is not the content of the signals but rather the signals themselves that convey some sort of message to the brain.
Our ears, so often taken for granted, thus are a marvel of intricacy and design that leaves anything that man can produce in the shade as a cheap imitation. Your hearing can never be replaced. Don’t take it for granted.
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