Blood is a miraculous fluid within our body. With millions of cells flowing in the blood system like stars in outer space, this fluid has a complex structure and composition that performs many vital tasks essential for our survival. For those who reflect, blood offers much to ponder.

Blood production begins around the second or third week in the mother’s womb within the vitellus, a sac that resembles the yolk of a bird’s egg. This production then continues in the liver, spleen, thymus gland, and bone marrow, respectively. After birth, long bones take on this task, with spongy flat bones such as the skull, breastbone, vertebrae, and hip bones producing blood in adulthood.

In a healthy individual, blood volume is about 7% of body weight in adults and 8% in infants. For example, an adult weighing 70 kg (154 lb) has about 5 liters of blood, while a baby weighing 4 kg (8.8 lb) has about 0.32 liters of blood. Of the total blood volume, 55% consists of a fluid called plasma, while the remaining 45% is composed of cells. Plasma is 90–95% water, with the rest made up of fats, sugar, plasma proteins (albumin, globulin, fibrinogen), clotting factors, electrolytes (salts), and hormones. Blood cells, which constitute 45% of the blood, originate from the same stem cell and undergo specific differentiation processes. They then enter the bloodstream as three distinct cell types: erythrocytes (red blood cells), leukocytes (white blood cells), and platelets (thrombocytes). Of these cells, the red blood cells—which give blood its red color—are directly related to the condition known as “anemia.” A healthy adult has about 25 trillion blood cells (20–100 billion leukocytes/white blood cells, the rest are red blood cells). The average lifespan of a red blood cell is about 120 days. During these four months of life, they circulate the blood vessels in the body 300,000 times. There are about five million red blood cells in one cubic millimeter of blood. Erythrocytes that have completed their function and are worn out are recognized and destroyed by the cells (macrophages) responsible for destruction and are recycled in the bone marrow to be used in the production of new red blood cells [1].

The body maintains a balance between the rate of erythrocyte (red blood cell) destruction and production, ensuring a stable number of active erythrocytes in circulation. New red blood cells are continually produced and introduced into the circulatory system at an astonishing rate—2.4 million per second, or 208 billion per day.

Red blood cells are morphologically disc-shaped, with a diameter of 6.2–8.2 micrometers. If we line up each of our red blood cells side by side, their length would be 192,500 km (120,000 miles, which is about five times the length of the equator). If we stack the same cells on top of each other, the height of the resulting tower would be approximately 60,000 km. When the membranes of all cells are opened and spread out, the total surface area would be 3,100 m2 in men and 2,500 m2 in women. (one can compare this with a football field which is 7,500 m2). If we spread all the cells each touching another and without opening their membranes, they would cover an area of more than 1000 m2. The large surface area of red blood cells is a merciful design, as it allows for the rapid supply needed to meet the body’s high oxygen demand. Such a large surface divided into small units as many as 25 trillion cells enables rapid diffusion of a large amount of oxygen from the lungs to the red blood cells, and its transportation to other cells through blood vessels. The exchange time between blood plasma (where the cells are suspended) and the fluid surrounding the body’s cells is just three seconds. Such an extraordinary system of transportation and supply can only be the work of an infinite wisdom that knows every detail in its finest features.

Functions of blood

The vast majority of functions essential for our survival are carried out by blood. These include transporting vital substances—such as oxygen, glucose, amino acids, fatty acids, vitamins, and minerals—to the cells, and removing waste products like carbon dioxide, urea, and lactic acid produced through metabolism. Other essential tasks, such as preventing blood loss through coagulation, providing defense cells (antibodies) and their substances, transporting hormones, and regulating body temperature and water balance, are also crucial for the smooth operation of the body.

What is anemia?

Anemia is a blood disease that occurs as a result of insufficient number of red blood cells or their oxygen carrying capacity. The task of transporting oxygen in the blood is the task of a molecule called hemoglobin, which is found in red blood cells. Hemoglobin is a protein-like molecule that carries the oxygen it takes from the lungs to the tissues and the carbon dioxide it takes from the tissues to the lungs. It contains iron and gives the blood its red color. More than 98% of the oxygen in the body is loaded with hemoglobin, and 2% is dissolved in the blood plasma. There are approximately 270 million hemoglobin molecules in each red blood cell [2]. Anemia occurs if the amount of hemoglobin in a blood test is <13 g per deciliter (less than 13 grams) in men, <12 g in women, and <11 g in pregnant women. In children, these values vary according to age [3]. The number of patients with anemia in children and women of childbearing age in a society is accepted as an important public health indicator by the World Health Organization [4]. According to the World Health Organization, anemia affects

approximately one in four people worldwide, though its prevalence varies across countries and communities. The rates are 47.4% in preschool-aged children, 25.4% in school-aged children, 12.7% in men, 30.2% in women, 41.8% in pregnant women, and 23.9% in people aged 65 and over [5].

The causes of anemia can be grouped into three main categories: bleeding, reduced red blood cell production, and increased red blood cell destruction. There are many types of anemia, each with its own diagnosis and treatment methods, and some are genetically inherited. The first group of anemias arises from blood loss due to internal bleeding, often in the digestive tract, uterus, or bladder. If left unaddressed, such bleeding can lead to iron deficiency anemia over time. Therefore, it is important to examine these systems and organs closely in patients with unexplained iron deficiency anemia. A common example in this category is anemia caused by excessive menstrual bleeding, which should be carefully monitored in women and adolescent girls. The second group is called “aplastic anemias,” in which blood cells are not produced in the bone marrow, and the third group is called “hemolytic anemias.” In these types of anemia, erythrocytes lose their resistance due to intracellular or extracellular causes and break down easily. If the production of the bone marrow cannot compensate for these losses, severe, life-threatening anemia occurs in the acute or chronic stages [6]. Aplastic and hemolytic anemias, which can also be genetically inherited, are more serious and dangerous than the anemias mentioned in the first group. In these cases, depending on the severity of the disease, treatment methods such as splenectomy (removal of the spleen), lifelong blood transfusion or stem cell transplantation may be considered.

Iron deficiency anemia

This type of anemia occurs when the body does not have the amount of iron required for blood production. It is the most common type of anemia in all age groups worldwide. The element iron is found in the structure of hemoglobin and is essential for its production. Anemia occurs when the iron intake in the body is low. The oxygen amount transported to cells and tissues is not enough. As a result, various complaints and symptoms may begin to appear, including weakness, loss of appetite, difficulty concentrating, decreased mental function and physical stamina, dizziness, palpitations and shortness of breath that worsens with exertion, headache, fatigue, chest pain, tinnitus, cold hands and feet, pale skin, cravings for non-food substances like soil, ash, ice, or paper, pain and flattening of the tongue, nail deformities, and hair loss. In some patients with long-standing or mild anemia, these symptoms may go unnoticed. In such cases, anemia can be detected through a blood test [8].

Iron is essential for producing hemoglobin and is a crucial component for brain development in fetuses and newborns. It supports neurological development in infancy and early childhood and plays a key role in the formation of the myelin sheath—a substance that surrounds nerve cells. When myelin production is reduced, issues arise in nervous system development. If brain cells’ iron needs are unmet, body, cognitive, and mental health issues can emerge in later life. This condition can also affect babies born to mothers with iron deficiency anemia during pregnancy [7, 8]. Due to its importance, nutrition guidelines recommend giving additional iron supplements to babies [9].

When we look at the data of the World Health Organization on the frequency of anemia, it is seen that there is an increase in anemia rates in infancy, adolescence, pregnancy and old age (65 years and older). The problems caused by anemia in the elderly are as serious as those in infancy and childhood. The most common causes of anemia in the elderly are chronic diseases (such as kidney, lung, heart, endocrine, intestinal diseases), iron deficiency, B12 and folic acid deficiency. In this age group, it was observed that there was a decrease in mental functions, and an acceleration in the development of dementia, physical injuries, confusion, behavioral disorders and mortality rates due to anemia [10, 11, 12].

For all age groups, the primary goal of treatment is to identify and address the underlying cause of iron deficiency. Treating iron deficiency anemia is generally straightforward and effective. Iron supplements can be administered orally or intravenously, depending on the need. A diet rich in iron-containing foods, such as red meat, eggs, and green leafy vegetables, is recommended, along with vitamin C sources (e.g., oranges, lemons, grapefruit, rosehip, vine leaves, fresh red and green peppers, parsley) to enhance iron absorption. Infants, adolescents, pregnant women and the elderly, who are at higher risk for iron deficiency anemia, should be closely monitored. In each case, the levels of substances such as vitamin B12, folic acid, and zinc in the body should be evaluated along with iron, and any deficiencies should be supplemented as needed. Since iron from animal sources is more bioavailable than from plant sources, vegetarians may require additional iron and vitamin B12 supplementation [13, 14].

“Atoms, especially those that come as a caravan of sustenance, travel with an astonishing order and wisdom through layers of existence and in many different modes. They pace along as if consciously without losing their direction and are strained through the four filters (digestive organs) in the body. In obedience to a law of generosity, they embark on red blood cells to come to the rescue of body parts and cells which are in need of that sustenance.” (Bediuzzaman, Thirtieth Word)

References

1. Birbrair A, Frenette PS. Niche heterogeneity in the bone marrow. Ann N Y Acad Sci. 2016;1370:82-96.

2. D’Alessandro A ve ark. Red blood cell proteomics update: is there more to discover?, Blood Transfusion. 2017;15:182-187.

3. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. WHO, 2011.

4. Global Reference List of 100 Core Health Indicators (plus health-related SDGs). WHO, 2018.

5. de Benoist B et al., ed. Worldwide prevalence of anaemia 1993–2005. WHO Global Database on Anaemia Geneva, WHO, 2008.

6. Rodak BF. Hematology: Clinical Principles and Applications, Philadelphia: Saunders Elsevier, 2007.

7. Basu S et al. Effect of maternal iron deficiency anemia on fetal neural development. J Perinatol. 2018; 38:233–239.

8. Doom JR et al. Infant Iron Deficiency and Iron Supplementation Predict Adolescent Internalizing, Externalizing, and Social Problems. J Pediatr. 2018; 195:199–205.

9. WHO Guideline: Daily iron supplementation in infants and children. Geneva, 2016

10. Andro M ve ark. Anaemia and cognitive performances in the elderly: a systematic review. Eur J Neurol. 2013;20:1234-1240.

11. den Elzen WP et al. Effect of anemia and comorbidity on functional status and mortality in old age: results from the Leiden 85-plus study. CMAJ. 2009; 181:151–157.

12. Girelli D, Marchi G, Camaschella C. Anemia in the Elderly. Hemasphere. 2018; 2:e40.

13. Pawlak R, Berger J, BS, Hines I. Iron Status of Vegetarian Adults: A Review of Literature. Am J Lifestyle Med. 2016; 12:486–498.

14. Pawlak R. Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians? Am J Prev Med. 2015; 48:e11-e26

Do you know what hemoglobin does? You should, because it has been perfectly created to keep you alive!

Hemoglobin is one of the miraculous molecules in the human body. While its most important function is to carry oxygen in the blood, it also plays a role in maintaining the body’s acid-base balance. It also carries carbon monoxide in the blood, though to a much lesser amount than oxygen. Hemoglobin is not yet free to roam in the blood; it is carried in red blood cells, which act as hemoglobin sacs. Red blood cells have almost no other function but to carry hemoglobin. They lose all their organelles, including the nucleus, to be able to carry more hemoglobin – and hence, our oxygen.

Hemoglobin is produced in the bone marrow by combining the “hem” molecule with the “globin” molecule. The hem part is produced in the mitochondria of the red blood cell. Two succynil coenzyme “A”s and two glycine amino acids are combined to form pyrrole. Four pyrroles are then combined to form protoporphyrin, which is combined with the iron atom to produce the hem. Four hems are combined with four globins, a kind of protein, to produce one hemoglobin molecule. Since each hem has one iron atom, every hemoglobin has four iron atoms. And since an oxygen molecule binds with each iron atom, every hemoglobin can carry a total of four oxygen molecules – or eight oxygen atoms.

The makeup of hemoglobin along with its production steps is very complicated and it features a precise and intricate design.

Hemoglobin functions much like a truck that hauls oxygen. The blood circulates between the lungs and tissues thanks to the continuous work of the heart. As hemoglobin moves through the lungs it binds with oxygen and as it flows through tissues it releases the oxygen.

For this process to work, the bond between oxygen and hemoglobin can be neither too strong nor too weak. If it were too strong, oxygen would not be able to break free in the tissues, and the tissues would go without oxygen. If the bond were too weak, hemoglobin would not be able to bind with enough oxygen in the lungs, in which case the tissues would again not get oxygen.

There are basically two kinds of hemoglobin. The first type is found in fetuses, and it is called fetal hemoglobin (Hb-F). The other is found in adult humans and is called adult hemoglobin (Hb-A). Before being born, the fetus gets oxygen from the mother’s womb. To get more oxygen from the mother, fetal hemoglobin is designed to bind more strongly with oxygen. One is tempted to ask: Because fetal hemoglobin binds so strongly with oxygen, will the fetus’ tissues not be deprived of oxygen? Yet there is no need to worry. Because there is less oxygen in fetuses than in adult humans, this different hemoglobin easily breaks free from the oxygen in the low-oxygen environment. After the baby is born, the body produces Hb-A instead of Hb-F because it starts to breathe through its own lungs.

Hemoglobin is charged with carrying 97% of the oxygen carried in the blood. 3% of the oxygen is carried in dissolved form in plasma. Because an increase in dissolved oxygen leads to oxygen poisoning, it is not desirable at all. If one breathes from a tube containing 100% oxygen instead of atmospheric air containing 80% nitrogen, the amount of dissolved oxygen in the blood increases, causing oxygen poisoning.

Hemoglobin is designed to store some oxygen, too. At rest, there is 20 ml of oxygen in the hemoglobin of 100 ml of arterial blood. Only 5 milliliters of this oxygen will be given to cells. The remaining 15 milliliters remains in the hemoglobin. In other words, not all oxygen in the hemoglobin is transferred to the body’s tissues. This is a security measure against possible risks. In the event that blood does not come from the lungs, this stored oxygen is used so that life can continue, though for a short time. The same situation is experienced when we do not breathe for a long time.

Exercise

During exercise or work that requires physical effort, the amount of oxygen demanded by the body increases twenty-fold. The heart works faster as does circulatory system. Hemoglobin is supposed to get 20 times more oxygen from the lungs so that it can take 20 times more oxygen to the cells. Body temperature increases, too. Hemoglobin is designed to respond to all these changes. During exercise, hemoglobin starts to give almost all the oxygen to the tissues. When it gets back to the lungs, it is like an empty truck and can load more oxygen.

The exercising person breathes more deeply and quickly; thus, the lungs work faster, the heart pumps blood with greater force and speed, and the design of the hemoglobin is just good enough to carry more oxygen to the tissues.

Inflammatory diseases

Cellular metabolism speeds up when a person has an inflammatory disease. More oxygen is needed because the chemical reactions in cells gain speed. The body’s temperature increases; so, too, the amount of acids and carbon dioxide in the blood due to increase in metabolic rate. In addition, the amount of a very important molecule in the blood increases. This molecule is called diphosphoglycerate. It is charged with protecting the cell during inflammatory diseases and preventing cell death. Diphosphoglycerate coaxes hemoglobin to send more oxygen to the body’s tissues. As we can see, the body has been perfectly created to ensure it receives enough oxygen, even during illnesses!

Transfer of carbon dioxide

Hemoglobin is also assigned the task of carrying carbon dioxide. Carrying carbon dioxide in the blood is easier than carrying oxygen, as carbon dioxide is twenty times more water-soluble than oxygen. Doctors, therefore, do not have to make an extra effort to reduce the amount of carbon dioxide in blood, and it is enough to give oxygen to patients with breathing problems. If carbon dioxide were not easy to dispose of, we would face an enormous problem, because there is no way of disposing of carbon dioxide and it is virtually impossible to develop one.

A vast amount of the carbon dioxide in the blood (70%) is carried in the form of bicarbonate. First, carbon dioxide combines with water, as a result of which carbonic acid, and then bicarbonate, are produced. After these reactions, carbon dioxide hides in bicarbonate (HCO₃) and arrives at the lungs. Then bicarbonate combines with H⁺, by which carbonic acid (H₂CO₃) is made. Then water (H₂O) and carbon dioxide (CO₂ ) are produced. The carbon dioxide that breaks up from the bicarbonate is discharged through the lungs into the atmosphere. 7% of the dissolved carbon dioxide in the blood is carried in plasma and 23% in hemoglobin. That is to say, as hemoglobin travels from the lungs to the cells, it carries oxygen, and as it returns from the cells it loads off some of the carbon dioxide.

Acid-base balance

The pH value of human blood is 7.4, on average. It is vital for cells that the pH of the blood remain stable. The regulation of the acid (H⁺) ion concentration in body fluids is called the acid-base balance. Little changes in H⁺ ions cause enormous changes in cellular chemical reactions. The regulation of the balance of H⁺ ions is therefore crucial for the body’s internal balance.

Hemoglobin plays an important role in the acid-base balance of blood. If strong acids find their way into the bloodstream because of certain diseases, hemoglobin help prevent an increase in the amount of acid (and a decrease in pH) by binding with the acid or carbon dioxide. A similar role is also true for times when the amount of base rises.

When we study hemoglobin and the chemical substances and reactions it is involved in, we can see that they are all arranged extremely precisely, and everything is in its proper place.

White blood cells (leukocytes) are fewer in number and their duty is to fight against germs. How this process works is to be expounded by the immune system under a separate title. The red blood cells are my main building blocks and they are born by the dividing of the main cells in the bone marrow. After passing through a few phases, they lose their nucleus and are filled instead with hemoglobin, a magnificent substance containing iron. Hemoglobin’s most vital function is its binding oxygen and then carbon dioxide after releasing it. Hemoglobin reaches everywhere, traveling with the blood stream. When it comes to the lungs, hemoglobin dumps the carbon dioxide and replaces is with oxygen. Then it supplies this oxygen to the cells and removes the carbon dioxide, which is produced by burning organic compounds. So its short life passes with the same ceaseless cycle to continue your life. Hemoglobin molecules’ longevity is approximately 120 days. They contain no cell elements like ribosome, mitochondria, and nucleus and therefore cannot repair themselves. They simply die when they get old. Sad? Not at all! Red blood cells fulfill the duty they were created for and leave the stage for new ones. They are broken down in the liver and bone marrow and the iron they contain is absorbed. A certain part is transformed into bilirubin, giving bile its yellow color. As you see, nothing is truly wasted.

The red blood cells in circulation number around 25 trillion, and this number does not vary greatly, as the dying ones are constantly replaced. Their measuring gives doctors an idea about possible diseases. The amount depends on various factors’ reciprocal balance. A hormone (erythropoietin) secreted by the kidneys increases the rate of production of red blood cells, in response to falling levels of oxygen in the tissues. If you lose blood due to an accident or medical operation, the stem cells in the bone marrow receive an emergency alert to produce more red blood cells. On the other hand, if you get a blood transfer, stem cells are ordered to stop producing, due to the excess of red blood cells. You see, even such basic knowledge about bodily systems fills the learner with wonder.

Deficiency of red blood cells, scientifically known as anemia, should not be ignored. It results in pallor and weariness; you feel like sleeping more. In order to avoid this condition, your body needs different things such as group B vitamins (B6, B11, B12), vitamin C, amino acids, and iron. Since it is hard to pinpoint the deficient substance, doctors generally prescribe iron-rich multivitamin supplements.

Red blood cells divide into four types, which determine the blood groups A, B, 0, and AB. In addition to the blood group, another feature known as Rh (rhesus) factor is important to know particularly before a blood transfer. Transferring the wrong type of blood may result in death.

Platelets, which are scale-shaped cells and circulate with me are not independent; they are pieces which came off bigger cells. In a cubic millimeter of blood, 250 to 350 thousand of these little scales are found and their duty is of vital importance. If it weren’t for these pieces, the slightest cut could cause death because your bleeding would not stop. Clotting is a great blessing. It usually blocks the surface of a wound within five minutes, stopping the flow of blood and saving your life. Clotting is realized through particular molecules in these minute scales as a result of a complex chain of reactions using enzymes, vitamins, and salts. Every step of this chain of reactions is another stitch to fix the wound. Other blood cells pile up and stick together behind this net and they dry up. If such clotting occurred inside the blood vessels, it would make a disastrous effect by blocking the bloodstream. I also have enzymes to break down little amounts of such clotting. As you see, everything is splendidly organized.

Peter! A blood test reveals very critical medical data. As I visit every organ, I exchange certain substances with them. Therefore, detection of an unusual substance in me can be an early warning for a disease. Nowadays, it even helps an early diagnosis of cancer.

It is not so easy for me to explain the wisdom behind all of my duties and capabilities. But to give you an idea, there are specialized departments for studying just me at medical faculties and research institutions throughout the world.

Blood is a highly specialized tissue circulating throughout the body to carry out essential functions for an organism. Some of the basic functions of blood can be listed as: warming or cooling the body, protecting it against infectious disease, supplying essential ingredients to the cells, getting rid of harmful and unwanted waste from cells, and carrying messengers to initiate physiochemical events at the cellular level.¹ An average adult has approximately five liters of blood which completes its cycle in several minutes.² Blood can be regarded as a flawless servant to human beings with a perfect design to fulfill delicate needs and tasks to maintain their lives. If blood stopped performing just one of these tasks in some way, the survival of humans would not be possible.

Plasma is one of the main components of human blood in which the red and white blood cells are suspended.³ These two “living cells” are responsible for the crucial job of maintaining the balance of the body. Blood cells have a definite life cycle, just as all living organisms do. The most generous and all-compassionate owner, God, even knows the needs of the tiniest creatures and for Him to recreate these two cells is as easy as resurrecting hundreds of thousands of fruits, vegetables and animals every spring. Interestingly, bone marrow acts as a factory to reproduce new blood cells in place of continuously dying cells.³

In order to generate energy required for all cellular processes, oxygen has to be carried into the cell and the resulting carbon dioxide should be carried away immediately. Red blood cells, known also as erythrocytes, contain an iron-rich protein called hemoglobin which performs this duty in an excellent way. Each red blood cell contains approximately 250 million hemoglobin molecules.⁴

Hemoglobin transports oxygen from the lungs to the rest of the body and carries carbon dioxide away from the body to the lungs by consecutive chemical events in harmony. Hemoglobin can bind oxygen and/or carbon dioxide reversibly and the preference for binding to either oxygen or carbon dioxide depends solely on the environment. Upon inhaling the air, the amount of oxygen will increase in the lungs and oxygen will bind to hemoglobin’s iron unit preferentially. Later, the heart pumps oxygen-rich blood all over the body to deliver it to where it is required. As blood travels through the body in artery veins, oxygen will be exchanged with the carbon dioxide, since the amount of carbon dioxide inside cells is higher than oxygen. Then, the bound carbon dioxide will be sent back to the lungs and this process will be cycled over and over again during the course of life.⁵ During these processes a lot of complex chemical and biological changes occur in a systematic way to optimize the speed, effectiveness and quantity of oxygen transportation.

Surprisingly, one hemoglobin unit can carry four oxygen molecules at the same time. However binding of four oxygen molecules does not happen at the same time, they rather prefer binding one after another. One of the most striking discoveries about these processes is that when the oxygen attaches itself to the iron in the hemoglobin, the shape of the hemoglobin changes and this phenomenon facilitates binding other oxygen molecules.⁶

At higher altitudes air contains less oxygen as compared to lower altitudes. In people accustomed to living at higher altitudes the amount of a chemical known as 2,3-BPG in blood was found to be higher than in people living at lower altitudes.6 Researchers showed that this chemical actually binds to hemoglobin to result in easier oxygen delivery in lower oxygen atmospheres. Without this chemical, at high altitudes people would start suffering from oxygen deficiency and some of the vital organs would start dying slowly. It is obvious that this is a decisive and self-evident proof that there is an ultimate power in the universe and He is the one Who is the most Merciful.

Also the hemoglobin in the fetus has a greater affinity for oxygen than its counterpart in adults. Fetal hemoglobin uses maternal oxygen from the mother’s bloodstream and this ability gives the fetus more access to oxygen for better survival.⁷ Otherwise, no baby would be able to grow fully in its mother’s womb. Divine mercy is aware of the need of even an incapable baby in the mother’s womb and His wisdom and generosity provide appropriate tools, decorations and ornaments to whoever is in need of them.

The human body can be seen as a perfect machine equipped with state-of-art components that functions magnificently to sustain human life without any conflict. It is designed to such an extent that even its slightest needs are satisfied with an amazing design planned by great wisdom and engineering. This beauty, extreme skill, and utmost perfection testify to the existence of the All-Wise Maker and All-Knowing Inscriber. Claiming that this masterpiece is not the work of a purposeful artist is as foolish as claiming that a beautiful painting is not the art of a good painter. Even in one of the sub-structures of red blood cells (hemoglobin) the highest degree of mastery and the exquisiteness of administration for each process show an irrefutable wise Creator who has utmost knowledge and proficiency. His unique power for marvelous creation is even more visible on the surface of the earth.

“He Who has created seven heavens in harmony. You do not see any fault or incongruity in the creation of the All-Merciful. Look yet again: can you see any rifts?” (Mulk 67:3)

Mutations somehow alter the sequences of genes responsible for producing hemoglobin and as a result of inheriting these genes, some kinds of hereditary diseases may occur in future generations, such as thalassemia and sickle-cell.⁸ Since hemoglobin in these cases does not have the ability to carry oxygen properly, in some extreme cases blood transfusion is necessary to supply healthy hemoglobin for survival of patients. Instead of producing super quality hemoglobin, mutations lead to malfunctioning of the system. No observable mutation can generate meaningful and healthy changes in an organism. Trying to explain the formation of these beautiful, complex, harmonious, and utterly perfect cells by chance or coincidence and attributing the creation of these systems to unconscious nature as their creator is far beyond any reasonable scientific explanation.

“Was he not once a mere drop of semen poured forth? Then he became a clot clinging (to the womb wall), and He created and fashioned (him) in due proportions.” (Qiyama 75:37-38)

Ibrahim Yildiz is a graduate student of chemistry at the Miller School of Medicine, University of Miami.

Notes

1. Previte, J. J. Human Physiology McGraw-Hill, 1982.

2. Cecie, S., Taggart, R. Biology: The Unity and Diversity of Life. California: Wadsworth, 1989.

3. Jones, B. D. Delmar’s Comprehensive Medical Terminology. Thomson Delmar Learning, 2000.

4. Roberts, M. B. V. Biology: A Functional Approach Cheltenham: Thomas Nelson and Sons, 1986.

5. Mehler, R. E. How the Circulatory System Works Blackwell , 2000.

6. Ganong, W. F. Review of Medical Physiology McGraw-Hill, 2005.

7. Champe, P. C., Richard, A. H. Biochemistry Lippincott Williams & Wilkins, 2005.

8. Steinberg, M. H. Disorders of Hemoglobin: Genetics, Pathophysiology, and Clinical Management. Cambridge University Press, 2001.

The air that we breathe consists of 78% nitrogen, 21% oxygen and 1% other gases, such as water, carbon dioxide, and carbon monoxide. First of all, the level of oxygen in the air is of extreme importance; that is, if the air were to contain 40% oxygen instead of the normal 21%, then there would be no life on Earth. Most living organisms, if not all, would die due to oxygen poisoning. Their proteins and DNA would be oxidized and become non-functional. Metals would be corroded and trees would burn at slightly higher temperatures than normal.

Vertebrates have been equipped with two principal mechanisms to supply their cells with an adequate and continuous flow of oxygen. The first one is the circulatory system and the second one is oxygen-carrying molecules; hemoglobin in the red blood cells and myoglobin in the muscles. The air we breathe is filtered even before it reaches our lungs. Then, it dissolves in the mucus, a highly viscous material, which coats the inside of our lungs. Next, the dissolved oxygen diffuses into the blood through alveolar cells and the walls of the capillary vessels. Finally, the oxygen is picked up by the red blood cells; these are what make our blood red. The red color is due to a molecule called heme that is present in hemoglobin and myoglobin. Every heme molecule in hemoglobin can bind four oxygen molecules together. Every oxygen molecule bound to hemoglobin increases the affinity of hemoglobin to bind to another oxygen molecule. The hemoglobin becomes saturated if the dissolved oxygen is above a certain level; this can be seen in the lungs. If the level of dissolved oxygen drops below a certain level, as can be seen in tissues like the muscles, brain, and liver, then the oxygen molecules start to dissociate from the hemoglobin. Likewise, every dissociating oxygen molecule facilitates the dissociation of another oxygen molecule from the hemoglobin. This is one miraculous design that is known to us: a molecule devoid of any wisdom and intelligence grasps a very crucial cargo where it is abundant, carries it to a place where the cargo is most needed and less abundant, and releases it. The myoglobin in the muscle tissue then binds the oxygen and serves as an oxygen backup resource for times when there is inadequate oxygen supply during exertion.

Fetuses have their own specific hemoglobin, called hemoglobin-F, which is different from that of adult hemoglobin, hemoglobin-A. Before birth, the fetus gets its oxygen from the mother’s blood through the placenta. The higher affinity of hemoglobin-F than hemoglobin-A to oxygen makes the oxygen exchange between the maternal and fetal blood possible. It is interesting to note that right around the time of birth the fetus switches the production of hemoglobin-F to hemoglobin-A, as this is more efficient under normal breathing conditions. Our current knowledge is insufficient to completely understand how this switch-over occurs and how it is regulated. Future studies will shed light on this complex but magnificent mechanism of regulation and this superb design.

Why are we so dependent on oxygen? In fact, our energy metabolism is completely dependent on oxygen. The chemical breakdown of nutrients by a dozen enzymes releases energy, which as is cannot be stored or transferred to the places where it is required. We are equipped with a second mechanism, which involves another set of different proteins that converts the released chemical energy to a more useful and transferable molecular form, called ATP. ATP, which we can think of as small packages of energy, is the main form of energy within our cells that can be readily used by all reactions that require energy. The first set of enzymes abstracts electrons from the nutrients during their chemical breakdown. These so called high-energy electrons are transferred from one protein to the next by the second set of proteins that form the electron transport chain. The final acceptor of these electrons is molecular oxygen. If oxygen were not there to pick up the electrons at the end of this chain, the last protein (cytochrome oxidase) would lead to a dead end, as it would be rendered inactive with the electrons that it is carrying. This would make this superb design of complex mechanism useless and wasteful; the synthesis of every new and active cytochrome oxidase would require more energy than is produced in one cycle of an electron transfer in the absence of oxygen.

It has been known for some time that cells can sense the level of oxygen in their environment. They are equipped not only with a sensing mechanism, but also with a response mechanism, by which they can survive for a short period of time. In 1995, a protein called HIF (Hypoxia Inducible Factor) was identified and was shown to regulate cellular response to hypoxia, i.e., a reduced oxygen level. HIF is a transcription factor, which induces the expression of a set of genes that are required for survival under hypoxia. Several genes encoding glycolytic enzymes are regulated under hypoxia; this allows cells to produce ATP even without oxygen. Nevertheless, oxygen-independent energy generation is very inefficient and the yield is insufficient. Another set of genes induce angiogenesis (vascularization), or the making of new capillary vessels. VEGF (vascular endothelial growth factor) is one of the best known HIF target genes that induces the formation of new vessels where expressed.

One of the most remarkable aspects of HIF-based oxygen sensing is that under normal oxygen levels the HIF protein is simultaneously synthesized and degraded. Only under low levels of oxygen does HIF accumulate and induce its target genes. At first sight, this continuous production and degradation of HIF may look wasteful, whereas in reality it is a very well designed precautionary mechanism. The HIF protein is marked and sent for degradation by a class of enzymes called HPH/PHD. These enzymes also use the oxygen molecule to tag the HIF protein. If there were not enough oxygen around, HPH/PHD enzymes would not be able to tag HIF. As a result HIF accumulates and induces its target genes to ensure the adequate supply of oxygen. With this mechanism cells can quickly adapt and survive. Therefore, continuous production and degradation of HIF turns out to be a necessary precautionary measure which is taken against the risk of death arising from a low oxygen level.

This article is by no means a complete picture of the miraculous world of oxygen, perhaps it is no more than a brush stroke on the entire picture. Yet, even this incomplete glimpse is enough to help us realize how perfectly we have been created, and how well we are taken care of. We do not have even the slightest control over any of these aforementioned mechanisms. We breathe day and night, and every breath should be taken in gratitude to God, who created us as this masterpiece.