Page 24 - Knowing The Truth

22 KNOWING THE TRUTH

What we call external stimuli, that is, an outside effect stimulating
our nerve endings such as light, sound, taste, smell and hardness, reach
our sense organs – the eye, the ear, the tongue, the nose and the skin. Here
the first stage begins: the nerve endings receive the stimulation and
convert it into an electric signal that can be transmitted by the nerves. In
the second stage these electric signals are carried to the relevant centers in
the brain related to sight, hearing, smell and taste. In the last stage, when
the brain perceives these signals, it gives the appropriate response.

Even though the process of hearing is regarded as a
very natural thing, a complex process is involved as
can be seen in the diagram below. Sound waves
strike the ear and, after passing through various
stages, are converted into electric signals which
afterwards reach the brain by way of the nerves.
Sounds are perceived in the hearing center of the
brain. Actually, the brain is insulated from sound;
that is, what we call the hearing center in the brain is
a place of complete silence. But, within this silence,
we perceive every outside noise and every
conversation around us. This is an amazing mystery.

Hearing
nerve

Eardrum
Bone lever
Sound waves Cochlea