Blood is a liquid that is created to give our bodies life. As long as it circulates within the body, it warms, cools, feeds and protects by cleansing the body of toxic substances. It is almost solely responsible for communication within our bodies. In addition, it immediately repairs any fractures in the walls of veins and so the system is rejuvenated.
On average, there is 1.32 gallons (5 litres) of blood in the body of a human weighing 132 pounds (60 kilograms). The heart can make this amount of blood circulate in the body easily within a minute. However, while running or exercising, this rate of circulation can increase to five times as high. Blood flows everywhere: from the roots of the hair to the toes, inside veins of varying sizes. The veins have been created of such a flawless structure that no clogging or sediments are formed. A variety of nutrients and heat are carried through this complex system.
The air that we breathe is the most crucial substance for our survival. The oxygen is as necessary for the cells' burning of sugars in energy production as it is for setting a log on fire. This is why oxygen has to be carried from the lungs to the cells. The blood circulatory system, resembling a complicated network of pipelines, serves this very purpose.
Haemoglobin molecules inside the red blood cells carry the oxygen. Each one of the disk-shaped red blood cells carries about three hundred million haemoglobin molecules. The red blood cells display a flawless working order.
They not only carry the oxygen, but also release it wherever it is necessary, e.g. in a working muscle cell. Red blood cells deliver oxygen to tissues, carry the carbon dioxide, which is produced after the burning of sugar, back to the lungs and then leave it there. Following this, they again bind to oxygen and take it to the tissues.
Diagram showing gaseous exchange in the alveolus (above) and oxygen transport by haemoglobin (above)
A Pressure Balanced Fluid
Haemoglobin molecules also carry nitrogen monoxide (NO) gas in addition to oxygen. If this gas were not present in blood, its pressure would change constantly. Haemoglobin also regulates the amount of oxygen to be delivered to tissues by means of nitrogen monoxide. Amazingly, the source of this 'regulation" is nothing but a molecule, i.e. a mere collection of atoms that does not have a brain, eyes or conscious mind. Regulation of our bodies by a collection of atoms, of course, is a sign of the infinite wisdom of God Who created our bodies without flaws.
Cells of Ideal Design
Red blood cells make up the majority of all blood cells. An adult male blood contains thirty billion red cells, which would be enough to cover almost half the surface of a soccer field. These cells give colour to our blood and therefore to our skin.
Red cells look like discs. Due to their incredible flexibility, they can squeeze through capillaries and the minutest holes. If they were not so flexible, they would surely be stuck in various areas of the body. A capillary is normally four to five micrometres in diametre, whereas a red cell is about 7.5 micrometres (one micrometre is one thousandth of a millimetre, which is 0.000039 inch).
What would happen if red cells were not created with such flexibility? The researchers of diabetes gave some answers to this question. In diabetic patients, red blood cells loose their flexibility. This situation frequently gives way to clogging with inflexible red blood cells in the delicate tissues of the patients' eyes, which can lead to blindness.
Automatic Emergency System
The lifespan of a red blood cell is about 120 days after which they are removed by the spleen. This loss is balanced by the continuous production of new cells. Under normal conditions, 2.5 million red blood cells are generated per second, a number which can be increased if necessary. A hormone called 'erythroproietin" regulates the rate of generation. For example, as a result of heavy bleeding due to accident or nose bleeds, the loss is immediately balanced. In addition, the rate of generation is increased if the oxygen content of the air is reduced. For instance, while climbing at very high altitudes, due to the continuously declining oxygen content, the body automatically takes this action in order to make the most efficient use of the oxygen available.
Perfect Transportation System
The fluid portion of blood called plasma carries numerous other substances present in the body apart from just blood cells. Plasma is a clear yellowish fluid, which comprises 5% of the normal body weight. In this fluid, 90% of which is water, salts, minerals, carbo-hydrates, fats and hundreds of different types of proteins are suspended. Some of the proteins in the blood are transport proteins, which bind lipids and carry them to tissues. If the proteins did not in this way carry the lipids, the lipids would randomly float anywhere, giving way to fatal health problems.
Hormones in the plasma take on the role of special couriers. They facilitate com-munication between organs and cells by means of chemical messages.
Albumin is the most populous hormone in the plasma, which is in a sense a transporter. It binds lipids such as cholesterol, hormones, billirubin, a toxic yellow bile pigment, or medicines like penicilin. It leaves the poisonous substances in the liver and takes other nutrients and hormones to wherever they are needed.
When all these things are considered, it becomes clear that the body is created in an extremely detailed way. The abilities of a single protein to distinguish between lipid, hormone and medicine, and to determine not only the locations in need of them but also the amounts to be delivered, are all indications of flawless design. Furthermore, these surprising examples are only few out of dozens of thousands of different biochemical events taking place in a body. All of the trillions of molecules in the body work in a marvellous harmony. And, in fact, all of these molecules spring from the division of a single cell that forms in the womb of a mother. It is clear that this miraculous system of the human body is a wonderful artistry of God, Who created man from a single drop of water.
Special Control Mechanisms
Nutrients have to cross from the arteries through the artery wall, in order to penetrate into the necessary tissues. Although the artery wall has very small pores, no substance can penetrate it by itself. It is the blood pressure that facilitates this penetration. However, nutrients crossing over into the tissues in larger quantities than necessary causes inflammation in the tissues. Therefore, there is a special mechanism instituted for balancing blood pressure and withdrawing fluid back to the blood. This is the responsibility of albumin, which is larger than the pores in the artery wall and numerous enough in the blood to suck up the water like a sponge. If there were no albumin in the body, it would swell like a dry bean left in water.
On the contrary, materials in the blood should not enter the tissues of the brain uncontrolled, since unwanted substances can severely damage nerve cells (neurons). Therefore, the brain is protected against all possible scenarios of harm. Dense cell layers close off pores. All substances are required to pass through these layers as if passing through a security checkpoint, which facilitates a balanced flow of nutrients into the most sensitive organ of the whole body.
Thermostat in the Body
Apart from toxins, red blood cells, vitamins and other substances, blood also carries heat, a by-product of energy generation in the cells. Distributing and balancing body heat in accordance with the outside temperature is vitally important. If there were no heat distribution system in our bodies, our arms would overheat and the rest of the body would be cool when the arm muscles are used, which would greatly damage the metabolism. This is why heat is evenly distributed throughout the body, which is facilitated solely by the circulatory system. In decreasing the body-heat that is distributed all over the body, the perspiration system is activated. In addition, blood vessels enlarge under the skin, enabling excess heat in the blood to be transmitted to the outside air. This is why when we run or do other high-energy activities, our faces become red. Blood circulation is as responsible in preservation of the body heat as in cooling. In colder temperatures, the blood vessels under our skin shrink, which serves to reduce the amount of blood in the area where heat escape is most probable and hence to keep cooling to a minimum. The reason for a person's face turning white when cold is the precaution that the body automatically takes.
Everything taking place in the blood is extremely complicated and intertwined. Everything has been created flawlessly down to the smallest detail. In fact, there is such a wonderfully intricate balance in the bloodstream that the smallest breakdown could potentially cause very serious complications. Blood has been created with all its necessary properties by the One Creator in a moment. This Creator, the owner of superior knowledge and power, is God.