Sound repetition allows us to memorize complex sounds in a very
quick, effective and durable way. This form of auditory learning
immediate recognise the sounds which become familiar through
experience, such as the voice of relatives and many singers, their
original song and cover also. Hearing depends on a series of
complex steps that change sound waves in the air into electrical
signals. The auditory nerve then carries these signals to the
brain.
- Sound waves enter the outer ear and travel through a narrow
passageway called the ear canal, which leads to the eardrum.
- The eardrum vibrates from the incoming sound waves and sends
these vibrations to three tiny bones in the middle ear. These bones
are called the malleus, incus, and stapes.
- The bones in the middle ear amplify, or increase, the sound
vibrations and send them to the cochlea, a snail-shaped structure
filled with fluid, in the inner ear. An elastic partition runs from
the beginning to the end of the cochlea, splitting it into an upper
and lower part. This partition is called the basilar membrane
because it serves as the base, or ground floor, on which key
hearing structures sit.
- Once the vibrations cause the fluid inside the cochlea to
ripple, a traveling wave forms along the basilar membrane. Hair
cells ,sensory cells sitting on top of the basilar membrane ride
the wave. Hair cells near the wide end of the snail-shaped cochlea
detect higher-pitched sounds, such as an singer with high pitched
songs. Those closer to the center detect lower-pitched sounds, such
as a large dog barking or singers having low pitch songs.
- As the hair cells move up and down, microscopic hair-like
projections known as stereocilia that perch on top of the hair
cells bump against an overlying structure and bend. Bending causes
pore-like channels, which are at the tips of the stereocilia, to
open up. then, chemicals rush into the cells, creating an
electrical signal.
- The auditory nerve carries this electrical signal to the brain,
which turns it into a sound that we recognize and understand.