We tend to overlook our skin, but it performs many vital functions for our bodies – including coming to our rescue in emergencies.

Since it is designed to function within very precise limits, our body is very susceptible to small temperature changes. Since abnormalities in these changes occur, the body has various mechanisms to keep its temperature constant. One of these mechanisms works by changing the amount of blood in the veins underneath the skin. When talking about body temperature, it is important to distinguish between the internal and external body temperature. The internal temperature is the temperature of the brain and internal organs, while the external body temperature is the temperature of the skin.

Normally, arteries that transport clean blood, and veins that carry dirty blood, are not connected; therefore clean and dirty blood never mix. However, as a consequence of some illnesses or birth defects, an abnormal bridge between arteries and veins may be present. This kind of condition is usually called arteriovenous shunts, or arteriovenous fistula. In these kinds of situations, blood is pumped directly from arteries to veins. In other words, clean blood flows towards dirty blood. Normally, the clean blood has to travel the body, providing oxygen and other supplements to cells, while collecting carbon dioxide and returning to the heart to be cleaned again.

An incredible network for the transportation of substances from the blood in arteries and veins has been created. If this system, known as the “capillary network,” did not exist, none of our organs could be fed, and the circulatory system would not be able to provide its vital function.

The system is necessary for two reasons. The speed of the blood in the arteries and veins is too fast for anything to be transported to the organs, and their walls are too thick to allow transportation of substances. Therefore, the blood travels from the arteries to the capillaries, and after the trading of oxygen and other substances with carbon dioxide is completed, it flows to the veins. If any kind of abnormalities exist, the blood flows directly from the arteries to the veins, therefore skipping the capillaries. As a consequence, the organs aren’t fed and the blood gathers in the veins without fulfilling its purpose. Naturally, the oxygen and nutrition balance of the organs gets messed up. The blood is pumped out of the heart with no purpose and heart failure becomes inevitable.

The capillary network has been assigned the task of communication between arteries and veins. The skins is our only organ where the blood flows directly from arteries to veins; AV shunts accomplish a very important duty in this function.

There is a network of veins underneath the skin. The number of veins in this network is so many that if they were completely filled up, they could hold up to two liters of blood in the skin. Blood is pumped to the skin for two purposes: to provide oxygen and nutrients to the cells, and to collect carbon dioxide and waste products in the cells, as is done with every organ; and to monitor the internal temperature of the body by sending blood to the skin if the temperature gets too high, similar to what radiators in cars do when the engine gets too hot.

There is also the subcutaneous fat tissue underneath the skin which acts as an insulator. The vein network mentioned above is inside this fat tissue. There is a continuous flow of blood from the capillaries that feed the skin towards this network of veins. Moreover, especially in areas where the skin is exposed – such as the hands, feet, face and ears – there is a blood flow from the small arteries towards this network of veins. Contrary to other organs in the body, blood flows directly from the arteries to the veins. If this direct blood flow did not exist, the amount of blood in the skin’s veins would be close to zero, because the amount of blood necessary for skin nutrition is very little. However when the internal temperature rises too much, the amount of blood, which is normally close to zero, can suddenly increase to as much as 30% of the blood pumped by the heart. In this case, the body’s internal temperature is being transported to the skin. This is an incredibly efficient cooling system. However, if the weather is cold, the AV shunt veins are switched off and the skin’s blood flow is decreased until close to zero, therefore maintaining internal temperature. The fat tissue underneath the skin also has a very important function, as it acts as insulation, helping maintain temperature.

Body temperature and the body’s systems work in perfect coordination with each other. We can observe a very simplified version of this system in computer based air conditioners. However, when we reflect upon the incredibly sophisticated cooling system of the human body, we come to the conclusion that no other system is as perfect as that.

The hypothalamus, which has various vital duties for the brain, was also given the very important mission of controlling the body’s temperature. There are hot and cold heat receptors in various parts of the hypothalamus. When body temperature increases, these receptors are activated. As a consequence of this warning, skin veins all over the body expand. Simultaneous with the expansion of the veins, sweat is excreted.

The hypothalamus also has the duty of suppressing the mechanisms that produce heat throughout the body. For example, trembling is stopped and general metabolism is slowed down to decrease body temperature. As metabolism slows down, the production of heat becomes minimal, and cooling takes place. In conditions where the body temperature is too cold, some hormones secreted in the hypothalamus trigger the pituitary, and then the thyroid, hormones. Since thyroid hormones are responsible for increasing metabolism, body temperature increases. However if body temperature increases above normal, the control of the hypothalamus on the thyroid is reversed, and thyroid hormones are decreased, therefore decreasing body temperature.

There is one more reason for placing so many veins in the perfect and miraculous body’s skin: except for extremely cold weather conditions, quite a large amount of blood exists in these veins that are not used for nutritional purposes. Some of our organs act as storage for blood; two of the most important ones are the spleen and liver. Another one is the skin. In the course of losing blood, or an illness that increases the need for blood, the spleen and liver shrink. As a consequence of this shrinkage, the blood inside them is sent to the heart, through veins, and distributed to the areas in need of blood. This increases the heart rate.

A similar scenario occurs in the skin. The veins responsible for cooling shrink, and the blood they contain is sent to the heart with the help of the main veins, therefore helping the heart pump. During heavy loss of blood, the blood in the skin comes to the rescue. Patients who are losing blood have incredibly cold and pale skin. This is because the blood in the skin has reduced to a minimum.

The obverse of this happens in an illness called erythromelalgia, where more blood than normal flows from the arteries to the veins in the skin. This is mostly seen in the hands, feet, nose, and ears, since AV shunts are more prevalent in these areas of the skin. The symptom of this illness is burning pain, which is triggered by heat and soothed by cool temperatures. The nutrition of the skin decreases and some substances produced because of the absence of oxygen increases redness, heat, and pain, since some of the capillaries feeding the skin shut down and all of the blood flows from arteries to veins with the AV shunts.

Our skin protects our muscles and bones, and contributes to the beautiful aesthetic of our body. It provides our sense of touch, and is therefore a means for us to experience the material world, as well as providing temperature control for our bodies. It can clearly be seen that the relationship between the skin and the veins could not have evolved by the consequence of coincidence.

Harming our bodies or health is a betrayal against this incredible gift. One of the major ways people harm the body is through smoking cigarettes.

Smoking harms human health in countless ways. It is one of the main causes of many diseases, such as lung and throat cancer, along with cardiovascular and respiratory track diseases, such as chronic bronchitis. According to the latest report from the World Health Organization, smoking remains the fourth of the top ten risks that threaten human health. Approximately 20-30% of adult fatalities are caused by ailments contributed to by smoking. Recent studies have shown the negative effects smoking has on human reproductive functions.

Effects on fallopian tubes

Smoking has a negative impact on female reproductive organs; this impact is determined by how long, and how much, a woman smokes. It may cause infertility by damaging the fallopian tubes that serve as a ground for the egg to be fertilized by sperm. In many studies, the risk of damage to the fallopian tubes was very high – this danger increases if a woman starts smoking a pack a day before the age of 18.

Effects on female hormones

Many toxic substances in cigarette smoke, including nicotine, directly inhibits the activity of the enzyme called aromatase, which plays a major role in the synthesis of the female hormone (estrogen) in the ovaries. Depending on the biological function, estrogen can be found in three different forms: as estrone, estriol and estradiol. Polyaromatic hydrocarbons found in cigarette smoke stimulate the microsomal cytochrome P-450 enzyme system that degrades hormones in the liver and, consequentially, increases conversion of estradiol with high biologic activity into estriol with the lowest activity. Alkaloids, one of the harmful substances found in cigarette smoke, were discovered to prevent production of progesterone in the ovaries. This plays a role in preparing the womb and in continuation of the pregnancy during the first three months. Therefore, smoking leads to progesterone deficiency during the early stages of pregnancy, causing miscarriages.

Effects on the maturation of the egg

The concentrations of the FSH hormone that is involved in the maturation of reproductive cells in the ovaries are especially high in young female smokers. In other words, a resistance develops against the FSH hormone in the ovaries and higher FSH hormone levels are required for the maturation of the egg. Thus, fertilization problems and missed periods can occur because of an absent reproductive cell. During the treatment of such patients with insufficient egg cell maturation, there is a 50% decrease in the success of the implantation (placement of the fertilized egg into the womb) and the continuation of the pregnancy in smokers when compared to nonsmokers. This means smoking significantly reduces ovarian functions, and ovarian stimulation becomes inadequate at earlier ages in women.

The negative effects of smoking on the reproductive system are also observed during the implementation of reproduction methods such as in vitro fertilization and assisted fertility technologies. The presence of high androgenic hormone levels (pre-metabolites of gender related hormones: androstenedione, DHEAS and testosterone/SHBG) in female smokers has been found to decrease the possibility of pregnancy during in vitro fertilization efforts.

Effects during pregnancy

There are many harmful consequences of smoking during pregnancy, especially for older women who are pregnant. Some of these consequences are premature birth, miscarriage, retardation of development, inadequate baby weight, perinatal mortality, ectopic pregnancy, placental praevia, and placental abruption. Placental praevia is the abnormal placement of placenta in the womb. In this case, depending on the excessive bleeding that occurs after the eighth month of gestation, the lives of the mother and fetus become imperiled, and fetal development is hindered. Placental abruption occurs depending on the premature separation of placenta from the womb, causing excessive bleeding that can also endanger the lives of the mother and baby.

In pregnant smokers, the postnatal ratio of infant mortality and disability increases as a consequence of deficiencies involving lung function and nerve development. These effects are directly proportional to how much a woman smokes. There are also negative impacts when a pregnant woman is exposed to second hand smoke by a spouse or close friend. Harmful metabolites of nicotine reach the baby via the placenta. Furthermore, nicotine is degraded slowly in the liver of a pregnant woman. Inadequate baby weight is related to smoking dosage and time.

Due to smoking in the early stages of pregnancy, the hormone levels of estriol, estradiol, progesterone and hCG, hPL which is secreted from the placenta, have been found to decrease. This reduction, which is observed in parallel with the amount of smoking, can result in miscarriages.

Toxic polyaromatic hydrocarbons have been found to accumulate at elevated ratios in the wombs of women who were exposed to cigarette smoke for a long time. During pregnancy, this situation leads to the deterioration of sertoli cells located in the reproductive glands of male fetuses. These glands assist in sperm production during adulthood, and damage to them can therefore cause a reduction in sperm generation.

An insufficient placental development occurs because of the negative effects of nicotine, cadmiums, and polyaromatic hydrocarbons damage the reproduction of trophoblast cells that make up the placenta. This situation explains the increasing miscarriage ratios among female smokers.

The free T4/TSH ratio in the serum of the umbilical cord, which connects the fetus to the placenta, increases in the babies of smokers compared to those of nonsmokers. This means that in babies of smokers, the thyroid glands may become overactive during birth. Depending on a mother’s smoking habits, this hyperactivity of the fetal thyroid increases the metabolic speed and the amount of consumed oxygen in the body, thus leading to the inadequate development of fetus.

Menopause occurs two-to-four years earlier due in women who smoke, as compared to non-smokers. This is due to the aging of the eggs. The risk of entering menopause before the age of 45 in women who quit smoking at least ten years prior is 87% less than smokers who don’t quit. Therefore, the earlier a woman stops smoking, the lower the risk of early menopause.

Effects of smoking on men

In research studies, it has been discovered that smoking has many harmful effects on testicular development and functions. These effects can be summarized as follows:

• Reduction of semen volume and quality, increase in its adhesiveness, delay in its becoming liquid, and resulting deformation of the sperm.

• Reduction in the number and mobility of sperm cells.

• Delayed sperm nucleus maturation, deteriorated DNA integrity.

• Decrease in the production of testosterone from Leyding cells.

• Decrease in the egg fertilization capacity of the sperm.

As a consequence of these negative effects, male infertility can occur. As the amount of daily cigarette consumption increases, the number, strength, and types of anomalies also increase. In a study conducted in 2010, smoking has been showed to decrease zinc levels in the seminal plasma. As a result of this decrease, oxidative agents populate and DNA breaks take place, thus causing a disruption of sperm functions and infertility. Zinc deficiency at the same time leads to the destruction of seminiferous tubule cells where sperm cells are produced. Paternal smoking generates negative results during the application of assisted fertility methods (such as in vitro fertilization). The damage in the sperm DNA of the father can disrupt the embryo development. The risk of anomalies, cancer, and genetic diseases increases for the fetus.

Cigarette smoking clearly occupies a position as one of the worst enemies of mankind because of its destructive effects on the body. In this case, it does not make any sense to try finding excuses for smoking, for it is harmful to the body that has been loaned to us as a gift and a temporary property.

Cihanoglu is a professor of medicine in KATU, Trabzon, Turkey.

When we have been sitting or lying for a long time we can suffer from orthostatic hypotension due to an insufficient operation of the sympathetic nerves.

When we are lying down, the blood pressure in our arteries is pretty much equal throughout the body. When we stand up, the blood pressure is affected by the gravity and increases in the vessels under the heart, while decreasing in the brain. If we lie down again, the blood pressure in the arteries balances once again. If these changes cannot be naturally controlled, then we may suffer an increase or decrease in blood pressure, which could result in a fatal injury.

There are baroreceptors in the walls of main arteries whose tasks are to measure constantly the blood pressure and to send data (electrical signals) to the brain, informing it about the blood pressure in the body. These baroreceptors are located in the aorta as it leaves the heart and in the carotid artery as it enters the brain. With the onset of hypertension, the frequency of the signals that are sent to the brain increases and this drops in case of hypotension. The center of vessel movement in the brain, with regard to the frequency of electrical signals it receives, perceives a low or high blood pressure.

In the brain is a vasomotor center; this continuously controls the blood pressure and regulates it. This center constantly receives data about blood pressure. If the pressure decreases, the signals of the sympathetic nerve increase. If the pressure increases, the signals to the parasympathetic nerves are suppressed. As a result of sympathetic irritability, the heart begins to beat faster and stronger. It pumps much more blood in a unit of time, and thus the blood pressure increases. The arteries and veins also constrict and owing to this constriction in the arteries, the blood pressure increases further. As a consequence of constriction in the veins, the extra blood that is stored inside the veins is pumped into the heart. Now, as the heart is receiving greater volumes of blood, it works faster and contributes to the increase in the pressure. In the meantime, as a result of the suppression of parasympathetic nerve signals, the heart contracts faster and stronger, thus pumping much more blood.

As the blood pressure rises, the mechanism which is in charge of reducing the pressure via vasomotor center is triggered. While pressure is applied to the sympathetic nerves, the signals that are being sent to the heart and vessels decrease. Thus, the rate of systole and the amount of blood which is being pumped decreases. As the arteries receive less blood the volume of blood in the system falls off and as the arteries and veins expand, the blood pressure falls. Due to the dilatation in the veins, the volume of blood which is sent to the heart also decreases and as a result the heart pumps less blood and the blood pressure drops.

However, by triggering the parasympathetic nerves, the signals that are sent to the heart increase. This helps to slow the heart down and ensures that there is less blood pumping through the system. As a result, the blood pressure which has been reduced via the sympathetic system is reduced even further with the parasympathetic system. At this point, it is necessary for there to be a rapid drop in blood pressure, which is provided by the simultaneous functioning of different mechanisms.

We cannot control this system and it acts extremely rapidly and with great elegance. Even in the systole period, when the heart is pumping the blood and there is a short and sudden increase in pressure and in the diastole period, when the heart relaxes and there is a short and sudden decrease in pressure, the system is in charge and functioning at every second, operating to increase the hypotension and to decrease the hypertension. The average healthy human heart beats 70 times per minute. Consequently, there are 70 systole and 70 diastole stages every minute; thus a normal balance can be maintained by decreasing the pressure, which increases 70 times every minute, and by increasing the pressure, which decreases 70 times every minute; this is how the body maintains a normal balance. In other words, this system functions 140 times every minute. Is it possible that this system, which operates throughout our life, a system that we are not aware of, a system that is so sensitive and vital to our lives, a system the details of which have only recently been understood after centuries of observation could be nothing more than a coincidence?

The pressure regulating system mentioned above carries out other important tasks while we are sitting and standing as well. The amount of blood going to the brain is related to the maintenance of a difference in blood pressure between the arteries and veins and to the recirculation of blood. In connection with hypotension, the pressure in the veins to the brain decreases, in order to partially compensate for the decrease in the arteries. By preventing a decrease in the difference of pressure (perfusion pressure) between the two systems, the continuity of blood going to the brain can be maintained.

In addition, a small decrease in the blood going to the brain can lead to an increase in acidity and carbondioxide in the brain tissues and to a decrease in oxygen; this results in the dilatation of the blood vessels in the brain. When these systems go into action anyone who is not suffering from orthostatic hypotension will have a stable amount of oxygen consumption in the brain when they stand up, and thus not experience dizziness.

In fact, scenes from karate movies are wonderful displays of the perfect functioning of this system. In such scenes, the fighter will jump up, and then suddenly fall to the ground; he will then suddenly spring up and performs different moves. Certainly with every movement, the blood pressure changes suddenly, but as a sign of the Creator’s mercy and grace, the body is able to maintain a balance. Should not the person watching these scenes stand in amazement, thinking: “Oh my God, what an incredible order! How great is Your knowledge, power, wisdom and art!”

As mentioned at the beginning of the article with reference to an actual sad incident, when a person whose sympathetic system is not functioning normally suddenly stands up, they can suffer from dizziness and perhaps even faint due to irregular blood pressure.

For patients suffering from orthostatic hypotension patients, it is important that they do not stand up rapidly. In addition, exercises that encourage the use of leg muscles before standing up will help pump blood towards the brain.

Pause for a minute… What would happen if this miraculous system did not exist? Consider how much time it would take you to merely get out of bed every day!