Page 743 - Atlas of Creation Volume 2

Harun Yahya

nism, we hear sounds that are loud enough to shock the system at a reduced volume. These muscles are in-
voluntary, and come into operation automatically, in such a way that even if we are asleep and there is a loud
noise beside us, these muscles immediately contract and reduce the intensity of the vibration reaching the
inner ear.
The middle ear, which possesses such a flawless design, needs to maintain an important equilibrium.

The air pressure inside the middle ear has to be the same as that beyond the ear drum, in other words, the
same as the atmospheric air pressure. But this balance has been thought of, and a canal between the middle
ear and the outside world which allows an exchange of air has been built in. This canal is the Eustachean
tube, a hollow tube running from the inner ear to the oral cavity.

The Inner Ear

It will be seen that all we have examined so far consists of the vibrations in the outer and middle ear. The
vibrations are constantly passed forward, but so far there is still nothing apart from a mechanical motion. In
other words, there is as yet no sound.

The process whereby these mechanical motions begin to be turned into sound begins in the area known
as the inner ear. In the inner ear is a spiral-shaped organ filled with a liquid. This organ is called the cochlea.
The last part of the middle ear is the stirrup bone, which is linked to the cochlea by a membrane. The me-
chanical vibrations in the middle ear are sent on to the liquid in the inner ear by this connection.
The vibrations which reach the liquid in the inner ear set up wave effects in the liquid. The inner walls of

the cochlea are lined with small hair-like structures, called stereocilia, which are affected by this wave effect.
These tiny hairs move strictly in accordance with the motion of the liquid. If a loud noise is emitted, then
more hairs bend in a more powerful way. Every different frequency in the outside world sets up different ef-
fects in the hairs.
But what is the meaning of this movement of the hairs? What can the movement of the tiny hairs in the
cochlea in the inner ear have to do with listening to a concert of classical music, recognizing a friend's voice,

hearing the sound of a car, or distinguishing the millions of other kinds of sounds?
The answer is most interesting, and once more reveals the complexity of the design in the ear. Each of the
tiny hairs covering the inner walls of the cochlea is actually a mechanism which lies on top of 16,000 hair
cells. When these hairs sense a vibration, they move and push each other, just like dominos. This motion

opens channels in the membranes of the cells lying beneath the hairs. And this allows the inflow of ions into
the cells. When the hairs move in the opposite direction, these channels close again. Thus, this constant mo-

Utriculus Vestibular nerve
Sacculus
Common crus
Tympanic canal
Superior
semicircular canal Cochlea duct

Vestibule canal
Lateral
semicircular
canal
Cochlea
Ampulla

Vestibular nerve
Posterior semicircular Oval
canal window

The complex structure of the inner ear. Inside this complicated bone structure is found both the system that maintains our
balance, and also a very sensitive hearing system that turns vibrations into sound.

Adnan Oktar 741