The
human ear senses sound waves by detecting the change of air pressure
the sound waves that are then reflected off the Pinna (this is the
outer part of the ear) it then travels through the ear canal moving
the ear drum. The Eustachian tube also sometimes lets air in to
balance the air pressure between the ear and the atmosphere. The
Ossicles are small bones within the inner ear. These bones are called
the Malleus, Incu, and Stapes. The Malleus is attached to the ear
drum. When the
sound waves vibrate the eardrum it moves the Malleus that acts like a
lever moving from side to side. The Incus is attached to the end of
the Malleus which transmits these vibrations to the Stapes that’s
connected to the end of the Incus; at the other end of the Stapes is
the faceplate, which rests against the Cochlea. When sound
waves are generated the compression of air pressure pushes in on the
eardrum moving these small bones within the inner ear, this then
moves the stapes faceplate that pushes in on the Cochlea moving the
cochlear fluid. When the expansion of air pressure pulls out on the
eardrum it moves the Ossicles that moves the stapes faceplate that
pull’s on the Cochlea moving the cochlear fluid. This creates waves
in the fluid to represent the compression and expansion of air
pressure of the sound wave. The Cochlea is fluid filled and lined
with millions of little hair cells of different lengths and mass,
another part with in the cochlea is the organ of Corti this senses
which hair cells or vibrating and how strongly. The hair cells within
the Cochlea have a resonance frequency which means they will vibrate
in response to the certain frequencies. As the sound wave energy
enters the cochlea it moves much quicker through the fluid, the
motion of the fluid then moves the hair cells which are picked up by
the organ of Corti they are then converted into electrical energy
that reaches the Cochlear nerve which are then carried to the brain
as nerve impulses.
Protecting
your ears is very important; exposure to loud sound can lead to long
term hearing damage known as Tinnitus. Tinnitus is damage to the hair
cells inside the Cochlea that can end up to a ringing noise within
the ear. Certain types of drugs taken over a long period of time can
also damage your hearing. Listening to loud sounds that doesn’t
cause earache is capable of damaging your hearing, there is an old
rule: if you need to shout to be heard over noise it could be
damaging. To protect your ears from damage you should listen to music
at a reasonable level or wear ear plugs when exposed to loud noise.
