the miracle of the hormones

The Sensitive Calcium-Meters

The amount of calcium in the blood is a very important factor in human survival. In order for a human to survive, he needs to not only breathe and drink water, but he must also have a certain amount of calcium in his blood. If the level of calcium in the blood falls below what is required, death will result. Now, let us think of this hypothetical example: A container in front of you contains one liter of blood. This blood is to be transfused into a patient waiting for an operation. It has been discovered that there is a deficiency of calcium in this blood, but the amount of the deficiency has not been determined. You are asked to make a guess and supply the deficiency. You have been given a large container of powdered calcium to use.

How would you make this decision?

First, you would have to measure the amount of calcium in the blood in front of you. But you would need such advanced technological tools that you would have neither the time nor the opportunity to do it. In this situation, you would be completely helpless. The fact that you are unable to measure the amount of calcium in the blood in front of you may result in the patient's death.

Let us change our example slightly: Now you are given one liter of blood which contains no calcium, and you have to add the right amount of it. How many spoonfuls of calcium would you take from the container and add to the blood? What is the correct amount of this vital substance that must be added to one liter of blood?

You will never encounter this situation; the example has been given just to emphasize the importance of the amount of calcium in the blood. If a liter of blood were placed before you containing no calcium, the amount of calcium you would have to mix with it would be one tenth of a gram. In the five liters of blood in your body, there needs to be a total of only half a gram of calcium. If there is any more or less than this, serious illness or even death may result. Clearly, the human body has been created in a marvelously delicate balance. A person weighing 80 kilos requires only half a gram of calcium circulating in his blood-any more or less, and he will die.

Calcium ensures the operation of several vital functions in our bodies. Without calcium, the blood would not clot and a person could die from blood loss from to a small wound or even a scratch. Calcium also plays an important role in the transmission of nerve impulses. If nerve impulse transmissions were severed, death would result. Calcium also ensures that the muscles function and that the bones are healthy. The body of an adult person contains up to two kilograms of calcium, and of this, ninety-nine per cent is stored in the bones. The remainder is used in functions relative to body metabolism. Approximately 0.5 grams of calcium in the blood is sufficient for bodily functions.18

Above, we see the parathyroid glands. When the amount of calcium in the blood falls, the parathyroid releases a wonderfully designed hormone called parathormone. It is remarkable that a piece of flesh can recognize calcium, measure it and make a decision based on the results of that measurement.

As we said before, in 100 milliliters of blood, there is 10 milligrams of calcium-the equivalent of 0.1 gram in a liter. If the proportion falls from 10 mg. to 6-7 mg. (the total amount of calcium in the blood falls by 0.2 grams), tetany occurs, characterized by symptoms of painful muscle contractions and convulsions. These contractions happen first in the heart muscles and the muscles of the respiratory tract. The irregular contraction of these muscles makes the heart beat erratic and inhibits the respiratory function. Without treatment, the patient's heart will stop (or he will not be able to breathe). In either case, death results. As we can see, in order for such vital functions as heart beat and respiration to occur, only half a gram of calcium is needed.

If the amount of calcium in the blood increases to 12 mg. in 100 ml. (that is, if the total amount of calcium in the blood increases by one tenth of a gram), kidney stones could develop, the activity of the nervous system reflex could slow down, and the muscles could atrophy and (as a result) lose their strength. When the amount of calcium rises to 17 mg. per 100 ml. of blood, calcium phosphate spreads to every part of the body and poisons it.19 The fact that the human body is so dependent on a substance (and that this substance is used in several of this body's functions) demonstrates two important points: that human beings are created according to a wonderful plan, and that they are totally dependent on God Who created them.

After we have seen the importance of the amount of calcium in the blood, this question inevitably comes to mind: what is the mechanism that determines this amount that is so vital for life? The answer to this question reveals another wonder of creation. Buried inside the thyroid gland is another hormonal gland called the parathyroid. In order to ensure the balance of calcium in the body, this gland, working cooperatively with others, puts a highly intelligent plan into effect. The only function of the parathyroid is to measure how much calcium there is in our blood; it does this day and night throughout our whole lives, to keep the proportion of calcium at the ideal level.

If you placed the material seen on the left in front of someone and asked him what it was, he would not be able to recognize it unless he had special training. But the cells in our body immediately recognize calcium atoms from among the hundreds of materials in the blood.

Through the agency of a specially designed hormone that it produces (parathormone), the parathyroid regulates the level of calcium in the blood. If the level of calcium in the blood drops, it immediately secretes parathormone.20 This demonstrates a very important point: at the beginning of this section we asked whether you could determine the amount of calcium in a container of blood placed in front of you. We determined that, without laboratory devices specially designed for this task, you would not be able to succeed. Yet the tiny parathyroid can make a calculation that humans cannot do except in a laboratory. The cells that compose the parathyroid gland not only produce a hormone, but they also make measurements relative to the place where the hormone will be used.

How does a cell pick out the calcium atoms in the river of blood flowing in front of it? How can cells without eyes, ears or hands recognize calcium atoms among the millions of kinds of other substances in the blood such as salt, glucose, fat, amino acids, proteins, hormones, enzymes, lactic acid, carbon dioxide, nitrogenous waste, sodium, potassium, urea, uric acid, iron and sodium bicarbonate? How does a cell recognize calcium? How does it know how much calcium there should be in the blood? With what consciousness does it measure the calcium? With what intelligence does it decide whether there is too much or too little calcium present? Cells are tiny, only one percent of a millimeter in size, without conscious intelligence. The fact that they can successfully measure the amount of calcium in the blood is in itself a miracle.

18 Biyoloji 2 (Biology 2), p. 127
19 Biyoloji 2 (Biology 2), p. 129
20 Helena Curtis, Sue Barnes, Invitation To Biology, 4. Edition, New York, Worth Publisher, INC, August 1985, p. 472