The study of
the human being has long been a fascinating task for philosophers, physicians and poets. With the recent advances in science and technology
our knowledge about ourselves is increasing rapidly.
Humans are the only creatures that can stand upright naturally and
have large complex brains that they can use to synthesize sounds into speech. No other creature has this capability. The human ear is unique since, besides processing
sounds, it is also the organ of balance and equilibrium.
Our ability to stand upright and walk on two legs has brought many
advantages - specifically the opportunity to develop manual skills such as reading,
writing, driving and operating equipment.
Without our
eyes and ears and the ability to stand up, even the most modern communication systems will
not work, since the eyes and ears have to prepare the input and interpret the output.
Why was the
human being endowed with these attributes? Since
we are the most intelligent species and dominate this earth, it behooves us to reflect on
this.
Each part of
the human is uniquely and beautifully constructed in the most efficient design. Today, we will look at the amazing human ears and
see how clearly their construction points to a designer.
PLAIN BUT PERFECT!
Human ears
are not much to look at, yet behind these flaps of skin and cartilage lie structures of
such delicacy that they shame the most skillful craftsman, and of such reliable automatic
operation that they inspire awe in the most ingenious engineer. Working together, the structure of the outer,
middle, and inner ear perform acts of amazing range and virtuosity.
The ear has
three main parts: the outer, middle, and inner ear.
The outer
ear (all that we normally see) comprises the pinna, i.e., the flap of skin and cartilage
leading to a narrow tunnel that terminates in the eardrum.
The middle ear is an air filled cavity with the eardrum on one side and
piece of stretched skin known as the oval window on the other side, leading to the inner
ear, which contains the organs of hearing and the organ of balance.
SOUND, NOT WHAT YOU'D THINK
Sound as we
all know is really a form of motion. Invisible
sound waves travel through the air and set up corresponding vibrations in the outer ear. Usually when a sound wave travelling in air
reaches a solid or liquid surface, most of it is reflected, and thereby lost, and only a
small percentage is transmitted. But the
design of the ear allows this difficulty to be overcome.
As a result, sound is passed from the outside air to the liquid filled inner
ear without much loss. The inner ear is a
coiled tube divided in two by a thin tough sheet of tissue called the basdar membrane
which when examined under the microscope is seen to carry millions of fibers called hair
cells. The arrival of sound at the oval
window causes vibrations in the watery fluid within.
The to and fro movement of the fluid causes waves to travel along the
basilar membrane and thereby to the hair cells which are in contact with nerve fibers
which eventually form the auditory nerve that carries the message to the brain. The basilar membranes near the oval window respond
to high frequencies and the more distant parts to low frequencies. The message to the brain is therefore coded,
containing information about the pitch of the sound, its loudness and its quality.
The reason
we have two ears is because they form a stereo system allowing us to identify the place
from which the sound originated and also to identify whether the source is moving. The processing of sound by the ear and brain is so
accurate that clicks presented to one ear and then the other can be distinguished as
separate sounds when the time interval between them is as small as thirty microseconds.
YOU COULD HEAR A PINDROP...
The
virtuosity of the human hearing is as remarkable as its importance. A man can hear a mosquito buzzing outside the
window even though the power of the sound reaching him is no more than one quadrhhonth of
a watt. If 100 such buzzes (100,000,000,000,000,000) could be combined and converted
into electricity, there would be just enough power to light one reading lamp!
The
sensitivity of the ear is remarkable. The
movement of the eardrum in response to the minimum audible sound at a frequency of 1000 Hz
is about a thousand millionth of a centimeter: considerably less than the diameter of a
hydrogen atom. The movement of the basilar
membrane in response to the same sound is about a hundred times smaller - about the
diameter of an atomic nucleus!
This
represents the ultimate limit of performance. If
the, sensitivity of the ear was further increased, we would be conscious of the continual
bombardment of the eardrum by air molecules. Even
at the present limit it is surprising that we do not hear our own blood flowing through
the tiny vessels in the eardrum. This is so
because the ear can ignore signals which are constantly present.
MUSICIANS - ALL
The ear also
displays a judgement of pitch which is unequalled in the animal kingdom, and makes man the
most musical of all living animals. With no
musical training, we can distinguish the Note A sounded on the piano from the same note
played on a violin. We can also distinguish
the combination of different tones peculiar to each instrument that make up the note. We can reject the hubbub of a party while picking
out a single familiar voice. Even during
sleep the ear continues to function with incredible efficiency: because the brain can
interpret and select signals passed to it by the ear, a person can sleep soundly through
noisy traffic and the blaring of a neighbor's television , and yet awaken promptly at the
gentle urging of an alarm clock. A barking
dog, a squealing tire, a footstep -- can all be identified.
In fact, a normal ear can discriminate among some 400,000 sounds.
ALL THIS AND MORE!
The ears,
besides being a high fidelity stereophonic hearing system, are also responsible for
keeping the body in balance. This is done
with the help of two systems located within the inner ear.
Of all the
organs of the body, few can accomplish as much in so little a space as the ear. If an engineer could duplicate its functions, he
would have to compress into approximately one cubic inch a sound system tht includes an
impedance matcher, a wide range mechanical analyser, a mobile relay and amplification
unit, a multichannel transducer to convert mechanical energy to electrical energy, a
system to maintain a delicate hydraulic balance and an internal two-way communication
system. Even if he could perform this miracle
of miniaturization, he would be unable to match the ear's performance.
Many birds
and animals have learned to signal one another by their voices, both for warning and
recognition, but we, the humans, with our ears, our mobile tongues and throats, and our
large complex brains have learned to speak. We
have learned to be articulate, to attach arbitrary and abstract meaning to sounds,
synthesize words, and create a language which we then use as a tool to communicate our
experiences of the past and also our ideas and plans for future action. We now have innumerable languages across the
world. Humans are the only creatures capable
of achieving all this. The great strides we
are making in every field are evidence of this fact.
Even with our minimal numbers and our average sizes we dominate the planet
earth to the exclusion of all other creatures.
WHY ALL THIS?
Is there a
lesson to be learned from all this? Is there
a purpose? And if so, what is it? What is our responsibility?
It seems
abundantly clear to me that our main
responsibility is to use our ears and eyes and brain to recognize the role of the Almighty
God and to understand the purpose of our existence.
Using our
God given senses and our unique ability to explore this vast Universe we have learnt a
great deal about the physical laws that govern it. We
know that these laws are fixed and consistent; that they apply equally at all points
through out the Universe, without differentiation. This
attests to the fact that there is one Creator and His system is unchangeable. Thus, we can also appreciate the fact that the
same rules apply to all creatures, as they are part of the Universe too.
The Creator
thus appears to be very just and equitable. A
just God cannot create us as Jews, Christians and Hindus, etc., and then give each of
these groups different sets of standards. It
is totally contrary to the laws He is presenting all around us.
We have to
stop attributing our prejudices and fallacies to Him, rise above these wrong beliefs to
recognize the fact, so glaringly obvious to any person, who will use his mind, that God
created us all equal, but different, to test us with each other. Let us be appreciative of Him by using our senses
in the only way they should be used - to recognize Him as the absolute God and pledge our
allegiance to Him alone, the Creator of the brotherhood of mankind.
He is the One who granted you the
hearing, the eyesight and the brains. Rarely are you appreciative.
(Quran, 23:78)
-
Shakira Karipineni
