The Adrenal Glands

Almost everyone knows that there are two kidneys and that they are of vital importance, but most people do not know that there are two small pieces of tissue, weighing only 5-6 grams each, on top of both kidneys that are also of vital importance.

When we examine these glands, called the adrenal glands, each one is two separate laboratories. The first of these is the external part of the adrenal gland (the adrenal cortex), which produces three different hormones; the second is the internal part of the adrenal gland (the adrenal medulla), which produces two different hormones. The hormones produced by these glands are so important that the secretion of too much or too little of them results in death.22

The Fight or Flight System

Adrenaline is secreted immediately in the body of a pilot whose airplane malfunctions. This fluid sends more sugar and blood to the brain, making the pilot more attentive. His blood pressure and heartbeat increase, making him more alert. These are only a few of the changes that adrenaline causes in the pilot's body.

Some people owe their lives to a miraculous hormone called adrenaline: when these people are in danger, this fluid makes them stronger, more agile, faster and more attentive. It even doubles their physical capacities as if they had drunk a very powerful potion to give them strength. For example, a pilot notices a mechanical failure in his plane while flying. After a mechanical failure, which threatened to bring down his plane, a heroic pilot lands safely at the airport, saving the lives of hundreds of passengers. But there is a very important point that journalists usually fail to add: what saved the lives of the pilot and the passengers was that marvelous fluid mentioned above.

The fluid sent an alarm to the pilot's brain cells, causing more blood and sugar to be sent to his brain and made him more alert. At the same time, it increased his heartbeat and blood pressure, enabling him to move faster and be more attentive. His respiratory system capacity increased so that he could utilize more oxygen (and more blood could flow to his brain and muscle cells). His muscles and limbs became more intensely focused and the increase in the level of sugar in his blood gave him the extra energy that he required.

Adrenaline (epinephrine) is produced and stored in the adrenal medulla—the inner portion of the adrenal glands. Everyone has this hormone in him all his life; you have it in you right now. If it is needed, the adrenal glands will produce it so that you may become stronger, faster, and much more alert. If you are in some danger, you will be given about twice your normal strength to enable you to fight against the source of the danger (or to run away) to save your life.

1. Adrenal glands 2. Kidney 3. Right adrenal gland 4. Right renal artery 5. Right renal vein	6. Interior vena cava 7. Celiac Trunk 8. Abdominal aorta 9. Left renal vein	10. Left renal artery 11. Left adrenal gland 12. Adrenal medulla 13. Adrenal cortex 14. Capsule
In the adrenal glands there are two separate laboratories that produce very important hormones. The first is the adrenal cortex; the other is the adrenal medulla. The hormones produced in these laboratories are essential for human life.

Although such an important hormone, the concentration of adrenaline in the bloodstream is surprisingly small compared to the work it does. It has been calculated, for example, that if the amount of blood in our bodies were compared to a lake 100 meters in diameter and two meters deep, the adrenaline in our blood would be the equivalent of one teaspoon of fluid poured into the lake.23

1. Anterior pituitary 2. Hypothalamus 3. Adrenal cortex	4. Corticosteroids 5. Body cells	a. Gluconeogenesis b. Relieves c. Physical stress
The adrenal cortex plays an important role in reducing stress on the body. When the body is under severe stress, the hypothalamus sends a command to the pituitary gland to secrete ACTH (adrenocorticotropic hormone). ACTH, on the other hand, stimulates the adrenal cortex, causing the production of corticosteroids. These corticosteroids ensure the production of glucose from molecules such as proteins, which contain no carbohydrates. As a result, the body receives extra energy and stress is reduced.

The powerful effect of a small amount of this fluid on the human body is the result of wonderful design. When we look at the functional system of an adrenaline hormone, we more clearly understand the perfection of God's creation.

1. Hypothalamus 2. Carotid sinus 3. Heart	4. Arteries 5. Adrenal gland
In times of danger, the body goes into a state of alarm by means of a link between the brain and the adrenal glands.

The physical requirements of a normal person will certainly not be the same as that of a person in danger. Consider the needs of a person who is confronted by a dangerous situation: he must run fast, his muscles must work more quickly, his blood pressure must rise, and his heart must beat more quickly. So, he will be able to run faster, escape more quickly or fight more strongly against the danger. How does all this happen?

When the danger occurs, an alarm button is pushed in the body, and the brain sends a lightening-fast command to the adrenal glands. The cells in the interior section of the adrenal gland then go into alarm mode and secrete adrenaline hormone to deal with the emergency. The adrenaline molecules mix with the blood and disperse throughout the various areas of the body.

Adrenaline molecules have a special function in the veins and arteries that ensures the vital organs receive a greater supply of blood at the times of danger, and to do this, they dilate the blood vessels going to the heart, brain and muscles. The cells surrounding the vessels obey the adrenaline and supply the extra blood required by the heart. In this way, the extra blood needed by the brain, muscles and heart is supplied.24

While dilating the blood vessels going to the heart, brain and muscles, adrenaline constricts the vessels that supply the liver and the skin to ensure extra support needed by the body. There is another reason for the reduced amount of blood pumped to the skin: in the likely case of a wound, the amount of blood loss would be reduced. The reason for paleness observed in the skin in times of excessive excitement is because less blood is pumped to the skin then.25

An error never occurs that dilates the vessels going to the heart (or the brain) that constricts vessels going to the liver (or skin); the adrenaline molecule knows what it must do. A microscopically small hormone adjusts the diameter of the hundreds of blood vessels in your body where the blood is to be directed.
For every organ in the body, the action of adrenaline is different; when the adrenaline molecule goes to the blood vessels, it causes them to dilate; when it goes to the heart, it quickens the contraction of the heart cells. This makes the heart beat faster and supplies the extra strength that the muscles need.

1. Nerve signal 2. ACHT 3. Medulla 4. Adrenal glands 5. Kidney	6. Epinephrine 7. Glucocorticoids (Cortisol) 8. Increased heart rate, breathing rate, blood sugar 9. Liver releases glucose
As we can see in the picture, when the woman sees the snake, she becomes afraid and an alarm button in her body is pushed. Her brain sends a lightening-fast command to her adrenal glands. The cells in the inner part of the adrenal glands go into a state of alarm and secrete adrenaline for the emergency. The adrenaline molecules mix with the blood and are distributed to various parts of the body. The body is then enabled to react appropriately to the danger. For example, the woman's heart beats faster, and the sugar in her blood increases, giving her muscles added strength and she is able to escape the danger.

When the adrenaline molecule reaches the muscle cells, the muscles can contract with much more strength. The adrenaline molecules that go to the liver command the cells located there to mix more sugar with the blood. This causes the amount of sugar in the blood to increase and supplies the extra fuel needed by the muscles.

This activity of the adrenaline hormone in the body requires a great amount of intelligence, knowledge and skill. This tiny molecule knows what it must do and when; when the body does not need it, the alarm mode is never set into operation. Apart from this, it knows very well to which cells it must go, and what kind of command it must give to them. Moreover, this shows that it is well acquainted with the cells, with the organs and their functions, and it never makes an error as to when the body must be taken out of this emergency mode.

If it made such an error, the body would be irreparably damaged. But these little molecules function with a keen awareness of their responsibility. How is it possible for an unconscious, lifeless fluid, without a brain, eyes or knowledge, and composed of a certain combination of atoms too small for the eye to see to act in such an intelligent, organized, and timely way?

This clearly shows that every molecule in our bodies is created by God and that, throughout our lives, every moment's activity is controlled by God's power, will and command. After knowing how the body works in detail, no one with intelligence can claim that living things, cells, hormones, molecules or atoms are the purposeless works of chance. God's power, strength and sublimely intelligent knowledge, witnessed to by creation, are manifested in every place and at every moment. As the Qur'an says:

What is in the heavens and in the Earth belongs to God. God encompasses all things. (Qur'an, 4: 126)

Ten Million People and One Gram of the Hormone Aldosterone

If the aldosterone of ten million people were pooled together, only one gram of the hormone would result. Despite the fact that there is so little of it in the human body, the function of this hormone is very important.

In order to survive, countless balances must be preserved in your body every moment. As a person lives his daily life, he is not aware of any of these balances. For example, at this moment various systems are adjusting your blood pressure. The "aldosterone" hormone produced in the adrenal glands has the duty of preventing a fall in your blood pressure and adjusting the sodium balance in your body.

In your body exists as little as one gram in ten million of aldosterone. Research has shown that from one ton of adrenal glands, only ten milligrams of aldosterone is secreted.26In order to obtain one gram of aldosterone, it would be necessary to collect the aldosterone secreted from the adrenal glands of a total of ten million people. The human body is created in such a delicate balance that a deficiency in such a small quantity of this hormone results in death.

As explained above, aldosterone has two purposes: to increase the concentration of sodium (Na+) in the blood and to raise blood pressure. These two requirements are intimately connected to each other and aldosterone is a finely designed solution for meeting these two needs at the same time. If the quantity of sodium in the blood increases, the fluid level in the blood also rises with it. This is because molecules of water have a tendency to go where sodium is high.

Here is where we see the excellence of the design of aldosterone. On the one hand, it increases the amount of sodium; on the other, it uses the capacity of sodium to absorb fluid. When the blood level of sodium falls, aldosterone warns the cells in the tiny tubes of the kidneys. These cells intercept the sodium ions in the urine and reabsorb them. This causes the sodium ions to enter the cells forming the tiny tubes, and from there they are released again into the blood.

a. Outside of cell	b. Inside of cell
Because there must be a certain level of sodium and potassium in the blood, the cells in the kidney channels reabsorb a sodium ion (Na+) and release a potassium ion (K+) to the urine. Aldosterone is responsible for ensuring this important balance.

In this way, the amount of sodium is raised, the ion balance is maintained, the amount of fluid in the blood is increased, and blood pressure is restored to its normal level. When the sodium ions in the tiny tubes of the kidneys are restored, potassium ions (K+) are secreted from the blood to the urine because the proportion of sodium and potassium in the blood mustbe at a very particular rate. The mineral proportion is very important to ensure the proper acid-base balance in the fluid inside and outside the cells, and for the proper functioning of the nervous system.
Aldosterone is produced in the exterior portion of the adrenal gland. The cells in this portion have never seen the cells in the depths of the kidneys (and there is no possibility for them to encounter them). How is it that these cells know how to produce the right hormone for the reabsorption of sodium and the release of potassium? How does the adrenal gland know how to balance electrolytes and reduce the blood pressure? Most people are unaware that such ions exist in their own bodies.

Every cell in the human body is created to fulfill a special function; they are given their special qualities and placed in an area where they can perform this function. In short, a human being is created, and every feature of his body is a proof of this creation.

He to Whom the kingdom of the heavens and the Earth belongs. He does not have a son and He has no partner in the Kingdom. He created everything and determined it most exactly. (Qur'an, 25: 2)

A Flawless Planning

The level of blood pressure is of vital importance for a human being.

The next system we will examine is a wonder of planning and design. As we examine the workings of this system, we must ask, "Could this system have come into being as the result of unconscious chance?"
This question is important because time, chance, and the results of natural law are the reasons offered by history's worst deceit for its denial of the existence of God; the theory of evolution bases its account of the development of living things on this foundation.

The deceit of evolution claims that human beings and everything else ultimately came into existence by chance. However, the system that we are about to examine is, by itself, enough to reveal the real nature of the myth of chance and to show the deceitful enterprise of evolution.

The system is constructed so that it will come into operation when there is a blood pressure drop. It begins its role when the blood pressure drops below a certain level, like a fire alarm sensor specially designed to detect smoke coming from a fire.

The angiotensiogen protein produced in the liver and the renin produced by the kidney cells come together for a common purpose. These two different materials produced in two different organs fit into each other like parts of a logo, demonstrating the flawless design of the body.

When the blood pressure falls, the alarm sounds because low blood pressure can be very serious. When the alarm sounds, a series of measures must be taken to raise it. These measures include the following:

1. The blood vessels must be constricted. (This constriction will cause a rise in blood pressure, as is the case when a garden hose is compressed in the end.)

2. More water must be absorbed from the kidneys and mixed with the blood to raise the blood fluid level.

3. A person must be made to drink water as soon as possible.

A flawless system has been placed in the depths of the human body to put these measures into effect.

At the moment when the blood pressure falls (or the amount of sodium in the blood becomes less), certain cells in the kidneys become aware of the problem. The Juxtaglomerular cells secrete a very important substance called "renin.27

It is a wonder that cells can detect a drop in blood pressure or in the amount of sodium present and then secrete renin, the first link in a long chain that raises blood pressure.
In blood plasma, there is a protein that normally has a neutral effect as it circulates in the blood. This protein, called angiotensiogen, is produced in the liver. The first stage of this incredible planning starts here. Angiotensiogen and renin have no functions of their own, but they were designed specially to unite with one another. How is it possible that they are specially produced like logo blocks designed to fit perfectly into one another?
Consider this: kidney cells and liver cells are far removed from one another. How is it that one of these groups of cells produces one part (renin) and the other group produces the other part (angiotensiogen) in such a way as to fit perfectly with the first part? Could this happen as the result of unconscious chance?

1. Kidney 2. Liver 3. Lung 4. Adrenal gland 5. Blood vessel (constricted)	a. Renin b. Angiotensiogen c. Angiotensin I d. ACE e. Anjiotensin II f. Aldosteron
When blood pressure falls, renin secreted by certain kidney cells and angiotensiogen secreted in the liver come together and unite, like two matching parts of a logo. After this union, an enzyme called ACE forms a molecule called angiotensin II. This molecule constricts the blood vessels and ensures the secretion of aldosterone in the kidneys. This hormone causes the kidneys to reabsorb much more fluid from the urine. This chain of operations adjusts the blood pressure, raising it to the proper level.

Certainly not! It is not possible that such a process could occur by chance.

Renin changes the composition of the angiotensiogen molecule, causing the emergence of a new molecule, angiotensin I:

Renin + Angiotensiogen --> Angiotensin I

This new molecule has no function either. Found in the lungs, an enzyme called Angiotensin Converting Enzyme (ACE for short) functions to break down the angiotensin I molecule. Because of this enzyme, angiotensin I changes into a different molecule, angiotensin II.

Angiotensin I + ACE enzyme --> Angiotensin II

Two different molecules produced in the kidneys and the liver act on each other and a new molecule is produced. Lung cells that have no relation to kidney cells and liver cells produce an enzyme to unite completely with this new molecule. Moreover, they produce this enzyme long before it unites with these molecules. How do lung cells produce the right enzyme for a process that has not yet developed to interact with a material that has not yet been produced? How does it know how to make an enzyme that will change a non-functional hormone into a functional hormone

Again, it is clear that each stage is a designed system. The angiotensin II produced as a result of these stages is a proof of design and planning. This enzyme has two vital functions that would lead the system to the desired end result: the first of these functions is the constriction of the blood vessels (the first of the three desired results that we enumerated at the beginning of this section). Angiotensin II stimulates the muscles surrounding the blood vessels and activates the mechanism that contracts these muscles. In this way, the muscles contract, narrowing the diameter of the blood vessels and raising the blood pressure.

Could this happen by unconscious chance?
Again, this is impossible; Angiotensin II is specially designed to constrict the blood vessels and these is no room for chance in this flawless design.

Another important function of angiotensin II is to summon into action the wonderful aldosterone hormone. Angiotensin II reaches the adrenal glands and gives the command to secrete aldosterone. This is another proof of planning: when aldosterone mixes with the blood, it causes the kidneys to absorb the fluid in the urine.

As a result, the blood pressure will rise. This is the second result we want to achieve.

The material produced in concerted effort (and according to a plan by the kidneys, lungs and liver) brings about the secretion of the hormone causing a rise in blood pressure. In order to do this, it is necessary that the kidney cells, lung cells and liver cells form a coalition.

Before all else, this coalition must investigate what they need to do when blood pressure drops to make a decision about the best way "to constrict the blood vessels" and "to ensure the secretion of aldosterone."

1. Hypothalamic receptors 2. Information taken from baroreceptors in the heart travel to the hypothalamus. 3. The adrenal glands produce the hormones that stimulate the thirst center. 4. When enough water is provided, the tongue, the stomach and the intestine send the message that the reserves are filled. 5. The hypothalamus orders the saliva glands to stop production, and the result is a dry mouth.
6. Adrenal gland 7. Kidney	8. Heart 9. Stomach
Many times in the course of a day we feel thirsty and so drink a glass of water. But we are generally unaware of what is happening in our bodies at that time. Cells in the various organs of the body determine the water needs of the body and work with one another in a series of operations by which a person is urged to drink water. We never think about where this urge comes from; we just drink the water that assists our bodies.

Later, they must again make an investigation and analyze the anatomy of the adrenal glands and that of the cells in the muscles of the blood vessels and determine the way in which they function. Later, they will have to determine the molecular make-up of Angiotensin II to cause the muscles of the blood vessels to contract, and the adrenal glands to secrete aldosterone.

That last thing that must be done is to determine how this molecule will be produced. Every organ must take responsibility for one stage in its production. In terms of the production plan, there is a three-stage assembly system in which every organ is given a function. The kidney will produce renin, the liver will produce angiotensiogen and the lungs will produce ACE. Afterwards, the cells must return to their normal roles.

If someone does not believe that this system was created by a supreme power according to a special plan, that person must accept the view that unconscious cells achieved this by the mechanisms of neo-Darwinism (mutation and natural selection). The claims of evolutionists are unbelievable and illogical because this system (comprised of the kidney, liver and lung cells), which is irreducibly complex, must have come into being all at once at the same time. The probability of this happening by chance would require very unlikely events. At the same time (and again ultimately by chance), cells would have had to be formed to measure the pressure in the kidneys, then aldosterone would have had to be formed in the adrenal gland, the kidney tube cells would have had to acquire a structure designed to respond to aldosterone, and the cells in the muscles of the blood vessels would have had to get a structure that could be affected by angiotensin II. Countless other elements would have had to be in place at the same moment for this system to come into being, and if just one element had been absent, the whole system would not have functioned.

A system as this could not come into being as a result of unconscious operations of chance. This system, created by the eternal intelligence and knowledge of God and placed in the human body, has worked perfectly in the bodies of every one of the millions of human beings that have ever existed (except in cases of illness). Human beings have become aware of the existence of this system through research done with the help of sophisticated technological tools. Every bit of research that is done makes it impossible to explain the existence of the systems operating in the human body in terms of the myth of chance. This is because human beings are created, and it is not possible to hide the magnificence of creation by creating imaginary and illogical scenarios.

At the beginning of this section, we listed three measures necessary to increase blood pressure. The third was the necessity of getting the person to drink more water. In order to get a person to drink water, he must want to drink it. This time, the unconscious cells of the lungs, kidneys and liver deep in the body must influence a person's psychology.

The required plan is just one more detail in the flawless system created by God. The angiotensin-II produced by the concerted efforts of the kidneys, lungs and liver goes to a special part of the brain and activates it. This area of the brain is the "thirst center" that stimulates a sense of thirst. But there, an impediment called the "blood-brain barrier," which protects the brain makes it very difficult for the angiotensin II to pass from the blood to the brain tissues. This protective system is found in several areas of the brain, and one of these is the "thirst center." Thanks to the special character created in angiotensin-II, it is able to stimulate the thirst center and to arouse the desire to drink water.28

Can this system have come to be by the operation of unconscious chance?

After so many proofs, there is nothing left to say to a person who answers "Yes." The heart and conscience of such a person has been blinded; he has been conditioned not to accept the truth. God reveals in the Qur'an what is to be said to such a person:

… Do you then disbelieve in Him Who created you from dust, then from a drop of sperm, and then formed you as a man? He is, however, God, my Lord, and I will not associate anything with my Lord. (Qur'an, 18: 37-38)

A Miraculous Medicine (Cortisol)

1. Adrenal gland

Shortly, we will examine the aspects of another marvel—a hormone called "Cortisol." But this hormone has such a varied function in the human body that we must note a point before we begin.

The fact that a hormone can activate a cell is in itself a wonder because, in order for a hormone to affect this cell, it must activate the inner systems of the cell. This happens either by attaching to a receptor on the membrane of the cell, or by direct entry into the cell and activating a mechanism inside. But in each case, it is necessary that the hormone molecule be specially designed for the cell it will act on. If there is the slightest incompatibility in the structure of the hormone molecule and its receptor, the cell will not be affected. For this reason, the relation between the hormone and the receptor on the cell it affects has been compared to a lock and a key.

When we examine the effects of cortisol, we discover a very important fact. God has created security systems in the human body and He has placed locks in the cells of each of these different security systems; only a single key can open these locks. For example, this key can be inside a capillary cell, or it can also be in a liver cell.

1. Liver 2. Blood vessel

Thanks to its flawless design, the cortisol hormone can affect the liver cells just as it affects the capillary vessels. This is compared to a lock-and-key relationship with the cells.

This allows different cells to go into concerted action towards a common goal. No doubt, this is an example of God's artistry in creation; it is also a proof of the evolutionist deceit. The fact that different cells are programmed to work together towards a common goal, and that there is a central system that makes this program work, shows once again the invalidity of the myth of chance as proposed by the theory of evolution.

The cortisol hormone works inside the human body fighting on different fronts against pain, wounds, infection, overheating, hypothermia, allergies, lack of oxygen, hunger, and factors that increase body temperature.

As we examine the functions of cortisol, we must not forget that unconscious cells that cannot know where it will be used produce this hormone. These cells can never be consciously aware of the fronts on which cortisol fights.

Now, let us examine briefly the functions performed by this wonder called "cortisol" produced in the adrenal glands, and let us see once again how the artistry of God is manifested in the aspects of the human body. At each stage, ask yourself if this system could have come into being by evolution, and the answer will show the real nature of the theory of evolution.

Kortizol Hormonunun Görevleri

It takes measures in advance to heal wounds:

Adrenaline prepares a person for the moment of danger, whereas cortisol prepares the human body for what is likely to happen after the danger has passed. For example, it mobilizes the amino acids to go into action in the case of a wound.29 At the moment a wound occurs, these amino acids are the raw materials that will be used in the reconstruction of the tissue.

It reduces the sense of pain when a wound occurs:

This is the reason that some people do not feel pain at the time they receive a wound (and even for some time afterwards).30As a result, a person can find the strength to defend himself, run away, or fight even though he has been wounded.

The sense of pain is communicated by the nerve cells. But how do the cells that produce the cortisol know the mechanism that slows down, and partially stops the electrical impulses of the nerve cells?

In times of emergency it converts fats and proteins into sugar:

When a person is injured, the cortisol hormone goes into action without his knowing it.

In order for body and brain cells to be nourished, sugar is required; all cells need a continuous supply of sugar, otherwise, the person will soon die.

When someone is hungry, if there are no nutrients from which sugar can be obtained, the amount of sugar in the blood will drop. In this situation, cortisol comes into play and does not allow the body to remain without sugar. It ensures the conversion of stored fats and proteins into sugar, keeping the level of blood sugar within safe limits.31

Fat or protein (or both) are converted to sugar. This function is really highly complex. To change one material into another is to completely alter the composition of the molecules. If a fat molecule or a protein molecule were enlarged trillions of times and placed on a table, most persons would not know which atoms had to exchange places with others. However, inside the cells are refineries that accomplish this change through a very complex operation. The cortisol hormone knows the stages in the process of this change. It is designed to open the lock that will allow this change to begin. How do the cells that produce cortisol know the shape of the key required to start the operation that will convert fat or protein to sugar? How do they know what operation is needed to convert the formula of the fat molecule (CH3-(CH2)n-COOH) into the formula of the sugar molecule (CH2OH)?

In emergencies it gives priority to the nourishment of the brain and heart:

Cortisol molecules go into operation in emergencies and produce a drop in the body's utilization of sugar. But here is another wonder; the effect of the emergency is not felt on vital organs such as the brain and the heart. To give an analogy, just as in times of emergency, economic resources are deployed in particular areas of a nation, so the cortisol molecules give a mobilization order and give priority to the nourishment of the heart and the brain, curtailing the nourishment of other cells.32

How do cortisol molecules know that some cells are more vital than others?

It arranges the contraction and constriction of the blood vessels:

There are highly efficient refineries within tiny cells converting fat to sugar.

Earlier we saw that blood vessels are not rigidly fixed pipes, but because the muscles around them can contract and relax, the diameter of the vessels can be changed when the need arises. The command to become narrow reaches the blood vessels by means of various hormones. Cortisol arranges the response of the blood vessels to the constricting and dilating factors that affect them, and thus performs another important function in emergencies.33

How does cortisol know the system according to which the muscles around the blood vessels contract, and how can it organize the response of these vessels to the contraction-dilation factors of the system?

It checks the movement of water:

Cortisol prevents fluid from entering cells when it is not required. Thus, it helps to maintain the stability of the blood volume. How does a cortisol molecule know that fluid has a tendency to enter the cells? And how does it know the methods required to keep the fluid outside? More importantly, how does it determine when fluid must be kept outside the cells, not all the time, but just at those times when it is necessary?

In times of danger, to prevent a rise in body temperature, it inhibits the production of the relevant hormone:

Another wonderful effect of the cortisol hormone is seen in the case of high fever. A rise in body temperature is a sign that the human body is fighting an illness. This rise in temperature requires that a person rest and sleep. The rise in temperature is not a side effect of the sickness; fever is a specially adjusted security precaution to force a person who is fighting an illness to rest. The rise in temperature is caused by the "temperature center" in the brain, which is activated by a substance called IL-1 (interleukin).

Cortisol is also designed to deal with excessive body temperature. When a person is in danger of death due to high body temperature, cortisol lowers the temperature by inhibiting the production of IL-1, which activates the temperature center.34

How does cortisol know that IL-1 raises a person's body temperature and that high body temperature is dangerous for a human being? How does it know where IL-1 is produced and how does it make a decision to inhibit its production?

It organizes the production of some proteins, which are very important for human life:

A rise in body temperature is caused by the temperature center in the brain. A complex molecule called IL-1 activates this center. If a condition becomes a threat, cortisol stops the secretion of this material.

When you are in a difficult situation, cortisol takes all your needs into account separately, one by one. It increases the production of hemoglobin, white corpuscles, and thrombocytes in the bone marrow and thereby raises their blood levels.35

A single molecule too small for the eye to detect has a number of particularities, skills and responsibilities. For this molecule to perform its functions, it must have been specially designed for these special tasks. This hormone is another instance of the harmony and flawless design in God's creation.

... My Lord encompasses all things in His knowledge so will you not pay heed? (Qur'an, 6: 80)