One Hundred Trillion
Cells, which act as micro-heaters, supply the
heat needed by our bodies.
In order for you to be able to read this page, your
body temperature must be at a certain level. If this
temperature falls or rises too much, you will die. For
this reason, some systems that keep the body temperature
at a definite level have been created and placed within
the human body. One of these remarkable systems is the
thyroxine hormone. The body reaches a certain temperature
as the result of the activities of its 100 trillion
cells. We can compare these cells to micro-heaters,
and the wonderful molecule that controls how much heat
each micro-heater must produce is the thyroxine hormone.
It is in itself a wonder that cells produce a certain
amount of heat as they do their work and that the total
amount of heat produced by the 100 trillion cells is
exactly the amount that is required for human beings
to survive. Moreover, the thyroxine molecules know how
much heat the cells must produce. Together with all
of this, the fact that the cells know how they can act
on the metabolism and raise the body's temperature is
one more wonder of creation.
A Delicate Control Mechanism
A highly advanced and organized system has been created
to regulate the amount of thyroxine secreted. The secretion
of thyroxine occurs again as a result of a chain of
command of a set of unconscious cells organized in a
highly disciplined hierarchy.
When enough thyroid hormone has been produced,
the hypothalamus stops the production of the thyroid-releasing
When thyroxine is needed, the brain of the hormonal
system-the hypothalamus-sends a command (the TRH-Thyroid-releasing
Hormone) to the conductor of the hormonal system orchestra
(the pituitary gland). When it receives the command,
the pituitary gland understands that the thyroid gland
must be activated and immediately sends a command (the
TSH-Thyroid Stimulating Hormone) to the thyroid gland.
The thyroid gland, as the last point in this chain of
command, immediately secretes thyroxine in compliance
and distributes it throughout the whole body by way
of the blood.
When there is need for thyroxine, the hypothalamus
sends a command to the pituitary gland (TRH).
The pituitary gland that receives the command
understands that the thyroid gland must be activated.
The pituitary gland immediately sends a command
to the thyroid gland (TSH). In compliance with
the order it receives, the thyroid gland immediately
produces thyroxine, and the thyroxine is distributed
throughout the body by the blood stream.
How is the amount of this hormone that needs to be
secreted determined? How is it that, except in cases
of illness, neither more nor less of this hormone than
is needed is secreted?
The amount of thyroxine secreted is determined by a
special system created by the great artistry of God.
This system is based on two separate, negative feedback
mechanisms and is an example of an incomparable wonder
of engineering design.
When the amount of thyroxine in the blood rises above
normal, the thyroxine hormone produces a very interesting
effect on the pituitary gland and sometimes directly
on the hypothalamus: it reduces the sensitivity of the
pituitary gland to the TRH hormone.
The function of the TRH hormone is to activate the
pituitary gland to send a command (the TSH hormone)
to the thyroid gland. This command is the second point
on the chain of command in the production of the thyroxine
The system is so intricately designed that the excess
thyroxine takes highly intelligent measures so that
the sources in which it is itself produced do not make
too much, and it interferes with and severes the chain
of command established for its own production. By this
means, when the thyroxine in the blood rises above normal,
the production of thyroxine is automatically curtained.
We can understand this more easily with some examples:
imagine that small intelligent machines were made in
a factory. These machines were made in three stages:
1. First stage: computer A sends a
production command to computer B.
2. Second stage: computer B translates
this command into another language and sends it to computer
3. Third stage: computer C begins
to produce the desired machines with the help of a robot.
Suddenly, production exceeds what is required and there
are more machines in stock than are needed. At this
stage, one section of the machines in stock goes to
computer B and removes the cable connecting computer
B with computer A. Now, computer B cannot receive a
command from computer A. Since the production command
cannot reach computer C, production ceases and the computers
in stock last until the supply runs out. When the stock
runs low, the cable connecting computer A with computer
B is again attached by the machines and production resumes.
If such machines were made which could supervise their
own production and that of the machines that produce
them so intelligently, a revolution in industry and
technology would be the result. In every human being,
there exists such a fantastic system of production occurring
A second system also determines the amount of thyroxine
produced. An increase in the amount of thyroxine affects
the cells in the hypothalamus. These cells reduce the
production of TRH and, therefore, the amount of TSH
secreted in the pituitary gland is reduced. By this
way, the production of thyroxine is slowed down.
1. Computer A sends a production order to computer
2. Computer B understands the order, translates
it, and sends it to computer C.
3. Computer C begins to produce the desired machines
with the aid of a robot mounted on it.
When too much stock has been accumulated, one of
these machines goes to computer B and cuts its connection
with computer A. As a result, computer A cannot
give a production command. This situation continues
until the stock is depleted.
Using the above factory example, it is useful to examine
this second system. The effect of the thyroxine on the
hypothalamus and its curtailment of the production of
TSH can be compared to the machines produced in our
imaginary factory that slow down the information flow
from that computer. Not only the communication between
computer A and computer B is cut, but computer A is
also slowed down, thus being prevented from sending
a command to computer B.
When the amount of thyroxine in the
blood is reduced, the system works in the reverse direction.
More commands are sent from computer A and the capacity
of computer B to receive these commands is increased.
As a result, the hypothalamus secretes more TRH hormone,
the pituitary gland becomes more sensitive to TRH, and
raises the production of the TSH hormone. In this way,
more thyroxine is produced and secreted.16
How does the thyroxine hormone know that the chain
of command must be broken in order to stop its production?
How do the cells in the hypothalamus know that, when
the level of thyroxine is high, its secretion must be
stopped and, when it is low, its secretion must be increased?
How did this flawless system come into being?
To think that this intricately planned system came
to be by time, chance, and natural law is more outside
the realm of sound thinking than to think that a computer
or a television could come into being by a similar process.
In order for this system to be able to function, hundreds
of specially designed molecular sized structures (which
we have not described in detail) are required. It is
a clear fact that this system was created by a supreme
intelligence, that is, by God.
Four Out of Ten Thousand Molecules
The amount of thyroxine secreted is determined by the
amazing system we have described above. But together
with all this, there is another remarkable system that
keeps the level of thyroxine in the blood stable in
times of crisis.
Thyroxine molecules are secreted by
the thyroid gland into the blood and must soon become
attached to molecules specially designed to transport
them in the blood. While they are attached to this molecule,
they cannot perform their function. Of the thousands
of thyroxine molecules, only a few freely circulate
in the blood. It is only about four out of ten thousand
thyroxine molecules that affect the metabolic speed
of the cells.17
After the free thyroxine molecules enter the target
cells, other thyroxine molecules that detach from their
carrier molecules take their place. The carrier molecules
serve as a storage reservoir to ensure that enough thyroxine
is ready when needed.
We have already seen how delicately the balance of
the amount of thyroxine required to affect the cells
is adjusted and the medical problems that can result
if the amount of thyroxine rises or falls. This delicate
balance involves a proportion of four free to ten thousand
bound thyroxine molecules. In the light of this, these
questions must be asked:
Who counted these trillions of molecules and decided
that only close to four out of ten thousand are needed
for the health of human beings? Who calculated that
nine thousand nine hundred ninety-six molecules out
of every ten thousand molecules must stand by idly?
Who foresees that there will be a reduction of the number
of these four molecules out of every ten thousand molecules
roaming in the veins, and releases more molecules? Who
made this incredible mathematical calculation and created
this system that has existed in every human ever born?
Certainly this example is a proof that God is sovereign
over everything both visible and invisible, that He
encompasses and determines most exactly the number of
all things on the face of the Earth.
So that He may know that they have
indeed transmitted the Messages of their Lord. He encompasses
what is in their hands and has counted the exact number
of everything. (Qur'an, 72: 28)
16 Biological Science: A Moleculer Approach,
17 Biological Science: A Moleculer Approach, p. 521