One Hundred Trillion Micro-Heaters

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 hormone.

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 hormone.

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 C.

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 every minute.

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 B. 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, p. 521
17 Biological Science: A Moleculer Approach, p. 521