The Dragonfly Story

Structure of the Ear

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The outer ear consists of the pinna, the part you can easily see and feel, and the ear canal.  The pinna helps to gather the sound waves around us, these sound waves travel down the ear canal where they strike the ear drum. The ear drum separates the outer and middle ear.  When sound waves strike the ear drum they cause it to vibrate, which in turn causes the three small bones in the middle ear to move.  These three small bones are collectively called the ossicals.  The ossicals consist of the malleus or hammer, incus or anvil, and stapes or stirrup, or easily known as the middle ear bones. the stirrup is connected to a tiny membrane on the inner ear called the oval window. The oval window forms the entrance to the inner ear or cochlea. The cochlea is coiled and filled with fluid. If we magnify a section of the cochlea, we can see that the inner cochlea is lined with tiny hair cells. When the bones in the middle ear move due to sound waves striking the ear drum, the stirrup pushes rhythmically of the oval window, when the oval window moves it causes the inner ear fluid to move and the hair cells to move backwards and forwards.  The movement of fluid and hair cells can be likened to the wind in a field of long grass, as the wind blows, the grass sways backwards and forwards.  This movement causes electrical impulses to be sent to the brain, which are the converted into the sounds we hear, anything which interferes with the journey of sound down the ear canal, past the ear drum or through the middle ear, will result in Conductive Hearing Loss.