Today, many people are interested in the effects of direct sunlight on the body, especially those who want to spend the summer with benefit for themselves, stock up on solar energy and get a beautiful healthy tan. What is solar radiation and what effect does it have on us?

Definition

The sun's rays (photo below) are a stream of radiation, which is represented by electromagnetic oscillations of waves of different lengths. The spectrum of radiation emitted by the sun is diverse and wide both in terms of wavelength and frequency, and in terms of its effect on the human body.

Types of sunbeams

There are several regions of the spectrum:

1. Gamma radiation.
2. X-ray radiation (wavelength - less than 170 nanometers).
3. Ultraviolet radiation (wavelength - 170-350 nm).
4. Sunlight (wavelength - 350-750 nm).
5. Infrared spectrum, which has a thermal effect (wavelengths - more than 750 nm).

In terms of biological influence on a living organism, ultraviolet rays of the sun are the most active. They contribute to the formation of sunburn, have a hormone-protective effect, stimulate the production of serotonin and other important components that increase vitality and vitality.

Ultraviolet radiation

In the ultraviolet spectrum, 3 classes of rays are distinguished, which affect the body in different ways:

1. A-rays (wavelength - 400-320 nanometers). They have the lowest level of radiation; they remain constant in the solar spectrum throughout the day and year. There are almost no barriers for them. The harmful effect of sunlight of this class on the body is the lowest, however, their constant presence accelerates the process of natural aging of the skin, because, penetrating to the growth layer, they damage the structure and base of the epidermis, destroying elastin and collagen fibers.
2. B-rays (wavelength - 320-280 nm). Only at certain times of the year and hours of the day do they reach the Earth. Depending on the geographic latitude and air temperature, they usually enter the atmosphere from 10:00 to 16:00. These rays of the sun take part in the activation of the synthesis of vitamin D3 in the body, which is their main positive property. However, with prolonged exposure to the skin, they are able to change the genome of cells in such a way that they uncontrollably begin to multiply and form cancer.
3. C-rays (wavelength - 280-170 nm). This is the most dangerous part of the UV spectrum, unconditionally provoking the development of cancer. But in nature, everything is very wisely arranged, and the harmful C rays of the sun, like most (90 percent) of the B rays, are absorbed by the ozone layer before reaching the surface of the Earth. So nature protects all living things from extinction.

Positive and negative impact

Depending on the duration, intensity, frequency of exposure to UV radiation, positive and negative effects develop in the human body. The former include the formation of vitamin D, the production of melanin and the formation of a beautiful, even tan, the synthesis of mediators regulating biorhythms, the production of an important regulator of the endocrine system - serotonin. That is why after the summer we feel a surge of strength, an increase in vitality, a good mood.

The negative effects of ultraviolet exposure are skin burns, damage to collagen fibers, the appearance of cosmetic defects in the form of hyperpigmentation, provoking cancer.

Synthesis of vitamin D

When exposed to the epidermis, the energy of solar radiation is converted into heat or spent on photochemical reactions, as a result of which various biochemical processes are carried out in the body.

Vitamin D is supplied in two ways:

• endogenous - due to the formation in the skin under the influence of UV rays B;
• exogenous - due to intake with food.

The endogenous pathway is a rather complex process of reactions that occur without the participation of enzymes, but with the mandatory participation of UV irradiation with B rays. With sufficient and regular insolation, the amount of vitamin D3 synthesized in the skin during photochemical reactions fully meets all the needs of the body.

Sunburn and vitamin D

The activity of photochemical processes in the skin directly depends on the spectrum and intensity of exposure to ultraviolet radiation and is inversely related to sunburn (degree of pigmentation). It has been proven that the more pronounced the tan, the more time it takes for the accumulation of provitamin D3 in the skin (instead of fifteen minutes, three hours).

From the point of view of physiology, this is understandable, since tanning is a protective mechanism of our skin, and the melanin layer formed in it acts as a certain barrier to both UV B rays, which serve as a mediator of photochemical processes, and class A rays, which provide the thermal stage of transformation in the skin provitamin D3 to vitamin D3.

But vitamin D supplied with food only compensates for the deficiency in case of insufficient production in the process of photochemical synthesis.

Formation of vitamin D when exposed to the sun

Today it has already been established by science that to meet the daily need for endogenous vitamin D3, it is enough to stay under open solar UV rays of class B for ten to twenty minutes. Another thing is that such rays are not always present in the solar spectrum. Their presence depends both on the season of the year and on the geographic latitude, since the Earth, during rotation, changes the thickness and angle of the atmospheric layer through which the sun's rays pass.

Therefore, the radiation of the sun is not constantly able to form vitamin D3 in the skin, but only when UV B rays are present in the spectrum.

Solar radiation in Russia

In our country, taking into account the geographical location, periods of solar radiation rich in UV rays of class B are unevenly distributed. For example, in Sochi, Makhachkala, Vladikavkaz they last about seven months (from March to October), and in Arkhangelsk, St. Petersburg, Syktyvkar last about three (from May to July) or even less. Add to this the number of cloudy days a year, the smoky atmosphere in large cities, and it becomes clear that most of the inhabitants of Russia experience a lack of hormonotropic solar exposure.

This is probably why we intuitively strive for the sun and rush to the southern beaches, while forgetting that the sun's rays in the south are completely different, unusual for our body, and, in addition to burns, can provoke strong hormonal and immune surges that can increase the risk of cancer and other ailments .

At the same time, the southern sun is able to heal, just a reasonable approach must be observed in everything.

Back in the Soviet time no one was afraid to sunbathe under the sun, sunbathing was considered an event that has a beneficial effect on health and helps strengthen immunity. People were convinced that the more you are under the sun in summer, the less you get sick in winter, and acne and rashes completely disappear on the skin after intense tanning.

Some traveled south and sunbathing to come home chocolate-skinned. But in recent years, doctors and cosmetologists have increasingly warned that prolonged exposure to the sun without applying sunscreen to the body is dangerous to health. What is it - an advertisement for sunscreens or environmental degradation?

As we know from the lessons physics, infrared rays make up the bulk of solar radiation. Only recently, scientists have discovered that these rays reach the deep layers of the skin and accelerate its aging. In addition, the infrared spectrum of sunlight contributes to the formation of free radicals that damage DNA cells. But the worst thing for the skin in the sun is ultraviolet radiation. It not only contributes to skin aging and lowers immunity, but can also lead to the degeneration of moles into melanoma.

Some Experts put the harmful effects of the sun on health and the impact on the occurrence of malignant neoplasms on the skin are questioned. However, as medical statistics show, skin cancer is five times less common in people living in the North than in the population of middle latitudes. In addition, the harmful effect of sunlight on the condition of the skin is proved by the fact that rural residents who work for a long time under the sun develop deep wrinkles on their faces very early, despite the fact that they, like urban women, devote a lot of time to skin care. behind the skin.

UV rays dry out skin, as a result of which it loses elasticity and ages early. The ozone layer of the Earth protects us from harmful ultraviolet rays, but after the Americans launched the famous Concorde satellite into space, this layer began to collapse. Therefore, now it is necessary to protect yourself from the sun's rays more intensively than before.

However, consider the sun dangerous and hide whole days from its rays the house does not follow. Moderate portions of the sun are necessary for the body, because without sunlight there would be no life in the world. Being 15 minutes under the direct rays of the sun, you speed up the metabolism in the body, improve muscle tone, the functioning of the immune and nervous systems. Without the sun, vitamin D is not synthesized in the body, which plays an important role in strengthening bones and preventing rickets in children. Sun deficiency increases the risk of colon, prostate, and breast cancer. That is why a moderate tan is good for our body, but you need to sunbathe in compliance with the following simple recommendations:

1. Choose the right time for sunbathing. Staying under the sun before 10 am and after 5 pm is the safest for health.
2. If you have body there are a large number of moles, it is best to completely refuse to tan. You also cannot go to the solarium.

3. Sunbathe gradually, stay under the sun for no more than 15 minutes on the first day. If your skin is dark and you tolerate the sun well, increase your exposure time by 10 minutes daily. But being in the sun for more than 30 minutes a day without the use of sunscreen is not recommended.

4. If after sunburn your skin turns red, this indicates that it has received a sunburn. Try to avoid excessive exposure to the sun, sunburn is an unpleasant and undesirable phenomenon. It can contribute to the development of skin cancer.
5. After swimming in sea rinse your body with fresh water. Salty water droplets refract the sun's rays and create a lens effect, which can cause skin burns.

6. Use sunscreen cosmetics for with SPF filter. Do not buy sunscreens and oils without knowing their ingredients.

As part of sunscreen creams there must be microparticles of mineral substances, such as titanium dioxide or zinc oxide. These substances are not absorbed into the skin, creating a protective barrier on the skin and reflecting the sun's rays. But do not forget that most of the sunscreens we sell are not resistant to water. This means that after each bath in the water they must be applied again to the body.

Taking advantage sunscreens You can gradually increase the time spent under the sun. Moreover, you can calculate the maximum allowable time like this: if your cream has an SPF index of 12, then multiply 12 by 10 and you get the number - 120 minutes, during which you can safely bask in the sun.

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Objective

The purpose of the work: To establish the positive and negative effects of solar insolation on the human body, to identify the significance of the sun for the human body, to formulate the basic rules for sunbathing, and also to determine the tactics of the behavior of people with neoplasms on the skin.

2. Introduction

The topic of practical work in biology I chose "The influence of sunlight on the human body." This topic is of great interest to me due to the fact that recently people have begun to spend more time in the sun. We began to visit solariums, we began to relax more often in southern countries. A tanned person looks more beautiful and successful, so we began to use more cosmetic products to attract a tan.

I analyzed the literature (including medical literature), used the resources of the Internet, conducted a sociological survey to study the level of awareness of my friends, acquaintances, and relatives about the effects of ultraviolet rays on the human body. Here's what I got out of it:

3. What is solar insolation?

Solar energy is the source of life on Earth. This is light and warmth, without which a person cannot live. At the same time, there is a minimum level of solar energy at which human life is comfortable. In this case, comfort means not only the presence of natural light, but also the state of health - lack of sunlight leads to various diseases. In addition, the energy of the sun can be used not only to provide a comfortable existence of living beings (humans, plants, animals) with light and heat, but also to obtain electrical and thermal energy. A quantitative indicator in assessing the flow of solar energy is a value that is called insolation.

Insolation - irradiation of surfaces with sunlight (solar radiation), the flow of solar radiation to the surface; irradiation of a surface or space by a parallel beam of rays coming from the direction in which the center of the solar disk is currently visible. Insolation is measured by the number of units of energy falling on a unit surface per unit of time.

The amount of insolation depends on:

From the height of the Sun above the horizon;

From the geographical latitude of the place;

From the angle of inclination of the earth's surface;

From the orientation of the earth's surface in relation to the sides of the horizon;

The indicator of insolation affects many areas of our life, ranging from the comfort of living and ending with energy.

3.1 Types of ultraviolet radiation.

The sun emits three types of ultraviolet rays. Each of these types affects the human body in different ways. Ultraviolet rays vary in wavelength.

Ultraviolet rays a.

These rays have a lower level of radiation. It used to be believed that they were harmless, however, it has now been proven that this is not the case. The level of these rays remains almost constant throughout the day and year. They even penetrate glass.

Ultra-violet rays BUT penetrate the skin, damage the structure of the skin, destroy collagen fibers and lead to the appearance of wrinkles. They also reduce skin elasticity, accelerate premature aging of the skin, weaken the skin's defense system, making it more susceptible to infections and, possibly, cancer.

Therefore, when buying photoprotective products, it is necessary to look at the presence in this cosmetic product of protective factors against type A rays.

UV rays B.

Rays of this type are emitted by the sun only at certain times of the year and hours of the day. Depending on the air temperature and geographic latitude, they penetrate the atmosphere from 10 am to 4 pm.

ultraviolet type AT cause more serious damage to the skin, as they interact with DNA molecules that are in skin cells. AT- rays damage the epidermis, which leads to sunburn. Ultraviolet rays cause sunburn, but lead to premature aging of the skin and the appearance of age spots on it, make the skin rough and rough, accelerate the appearance of wrinkles, and can provoke the development of precancerous diseases and skin cancer.

ultraviolet rays C.

C-rays have the greatest destructive power for the skin. However, the ozone layer of the Earth, located in the Earth's atmosphere, prevents the penetration of these rays to the Earth's surface. But if the ozone layer of the Earth's atmosphere is destroyed or there are holes in it, then we will fully feel the damage that these rays cause to the skin.

3.2 The Earth's ozone layer is the protective layer of the stratosphere.

The ozone layer is a part of the stratosphere at an altitude of 20 to 25 km, with the highest content of ozone, which is formed as a result of the action of ultraviolet radiation from the Sun on molecular oxygen.

The more ozone in the atmosphere, the more ultraviolet radiation it can absorb. Without protection, the radiation will be too intense and can cause significant damage and thermal burns to all living things, and can lead to skin cancer in humans. If all the ozone in the atmosphere is evenly distributed over an area of ​​45 square kilometers, its thickness will be only 0.3 cm.

The harm of ozone on the surface of the planet.

When exhaust gases and industrial emissions react with the sun's rays, ground-level ozone is formed as a result of photochemical reactions. This phenomenon usually occurs in metropolitan areas and large cities. Inhalation of such ozone is dangerous. Since this gas is a strong oxidizing agent, it can easily destroy living tissues. Not only people suffer, but also plants.

Destruction of the ozone layer.

In the 70s, during research, it was noticed that freon gas, which is used in air conditioners, refrigerators and spray cans, destroys ozone with great speed. Having risen in the upper layer of the atmosphere, freons emit chlorine, which decomposes ozone into ordinary and atomic oxygen. In the place of such interactions, an ozone hole is formed.

The first large ozone hole was discovered over Antarctica in 1985. Its diameter was about 1000 km. Subsequently, another large hole (smaller) was discovered over the Arctic, and now scientists know hundreds of such phenomena, although the largest one is still the one that occurs over Antarctica.

There are many reasons for the appearance of ozone holes, but the most important of them is human pollution. Nuclear tests have no less effect on the ozone layer. It is estimated that from 1952 to 1971 alone, about 3 million tons of harmful substances entered the atmosphere during nuclear explosions.

Jet planes also contribute to the emergence of ozone holes.

Another reason for the destruction of the ozone layer is mineral fertilizers, which, when applied to the ground, react with soil bacteria. In this case, nitrous oxide enters the atmosphere, from which oxides are formed.

That is why environmentalists are now sounding the alarm and trying to take all necessary measures to protect the ozone layer, and designers are developing environmentally friendly mechanisms (airplanes, rocket systems, ground vehicles) that emit less nitrogen oxides into the atmosphere.

What does the ozone layer protect against?

Ozone holes are ubiquitous, but as many factors change, they are covered by ozone from neighboring layers of the atmosphere. Those, in turn, become even thinner. The ozone layer acts as the only barrier to the destructive ultraviolet and radiation radiation of the sun. Without the ozone layer, the human immune system would be destroyed. According to scientists, a decrease in the ozone layer by only 1% increases the likelihood of cancer by 3-6%. A decrease in the amount of ozone in the atmosphere will unpredictably change the climate on the planet. Since the ozone layer traps heat that is dissipated from the Earth's surface, as the ozone layer is depleted, the climate will become colder, which will lead to natural disasters.

4. Pigment-forming function of the skin.

Being the outer cover of the body, the skin has specific properties aimed at protecting the body from various external influences. Light is an indispensable and obligatory part of the world around us, a source of heat and energy. Intense ultraviolet irradiation of the skin is accompanied by a response in the form of reddening of the skin with further formation of pigmentation in the skin. The pigment-forming function is to produce melanin pigment. In addition to melanin, the iron-containing blood pigment hemosiderin can be deposited in the skin, as well as trichosiderin - in red hair, carotene.

Protective function of the skin.

The skin largely protects the body from radiation exposure. Infrared rays are almost completely blocked by the stratum corneum, ultraviolet - partially. Penetrating into the skin, ultraviolet rays stimulate the production of a protective pigment - melanin, which absorbs these rays. In people of the Negroid race, almost all ultraviolet radiation is absorbed by a large amount of melanin in the skin, which provides protection from the high doses of radiant energy characteristic of those areas of the globe where these races live. Therefore, people living in hot countries have darker skin than people living in countries with a temperate climate.

4.1 Formation of moles on the human body.

Many are interested in the nature of the origin of moles on the human body. And this is not surprising, because at birth the baby's skin is clean and does not have such features. No one can say for sure where the next mole will appear, and also explain why they can appear and disappear.

The reasons for their appearance are different, but basically they are formed under the influence of a special hormone - melanotropin. In different people, it is contained in different anatomical zones and in different amounts. Experts have found that the level of melanotropin in the body determines the number of moles in specific areas.

Specialists in the field of medicine managed to make some discoveries and shed light on the mystery of the appearance of moles.

One of the common causes of moles on human skin is the harmful effects of the direct rays of the sun, namely, the ultraviolet that it contains. The bottom line is that under the influence of ultraviolet radiation, the skin begins to produce a pigment - melanin, which is the basis of all moles. Therefore, it is not surprising that people who are exposed to the sun for a long time of their lives may notice an increase in moles in size over time. Thus, most new moles appear precisely in the hot summer period, when a person is tanning in the sun and spending holidays by the sea. There is an opinion among medical professionals that an excessive number of moles on the human body can cause skin cancer - melanoma. Under the influence of the sun, some groups of moles can develop into a malignant tumor.

As other reasons for popping moles on the body, dermatologists distinguish:

Damage to the body by a viral infection, X-ray and radiation exposure, skin microtraumas, as well as long-term non-healing foci of diseases on the integument trigger the processes of grouping and moving pigmented cells to the outer layer of the epidermis.

Pathology of the liver.

Belonging to the skin to a light type.

Irrational distribution of energy in the body.

Hormonal changes in human life.

4.2 When should I see a doctor about moles?

When many moles appeared on the body, it is necessary to learn how to distinguish them according to the criterion of the danger of degeneration into a malignant tumor. All pigmented foci dermatologists are divided into groups such as:

Melanoma dangerous, posing a threat in terms of transformation into melanoma.

Melanogenic elements - harmless to the body, but causing discomfort in everyday life due to frequent trauma (during daily shaving or with constant friction on clothes).

How to understand that a mole is dangerous?

Doctors from the American Academy of Dermatologists have developed for non-specialists, that is, people without medical education, how to detect early signs of melanoma. They popularize a fairly effective method of self-diagnosis: the danger of a mole can be preliminarily assessed personally, and in case of suspicion, you can already contact a dermatologist directly. Use it to check how dangerous moles are on your body! The ABCDE test, developed by specialists from the United States, helps to identify signs of a mole's degeneration into any type of skin cancer, including melanoma. This method does not require any special tools and does not take much time. At the same time, not only moles or other neoplasms on the skin, but also the slightest spots that cause at least a shadow of suspicion are subject to verification using this simple test. It is also worth taking note of any new moles or growths. The ABCDE test is recommended to be performed every month, fully examining the entire body.

A symmetry (asymmetry): half or part of the mole is not like its other half. If the two halves are not identical, such a mole is considered asymmetrical, and this is already a warning sign!

Border: Birthmark borders are irregular, blurry, blurry, and poorly defined. A benign mole has smooth, even borders, unlike a malignant one.

C olor (color) The vast majority of benign moles on the entire surface are painted in one color and have a shade of brown. The presence of three colors on the surface of a mole is a prognostic unfavorable sign.

D iameter (diameter): Benign moles usually have a smaller diameter than malignant ones.

E volving (development): Ordinary benign moles look the same for a long time. Be on the lookout when a mole begins to develop or changes any of its characteristics, from those described above, in a short time!

Oncologists recommend seeking medical help if they detect the slightest changes in the shape, size and structure of a mole. Delay in visiting a medical institution or ignoring the signs of malignant transformation is fraught with neglect of the stage and death.

In Izhevsk, over the past 5 years, the specialists of the Republican Dermatovenerological Dispensary, together with oncologists, have been holding the Melanoma Day in May. On this day, any resident of Udmurtia can get an appointment with qualified specialists and show all their moles, as well as ask all their questions. During the consultation, patients are given competent recommendations on existing moles or patients are sent for further removal of moles using modern methods of treatment.

4.3 Methods for the study and removal of moles in modern conditions.

With the modern development of technology, the examination and removal of moles has become a quick and practically safe procedure. One of the main methods for the study of moles, in addition to visual examination, is the method of dermatoscopy. Dermoscopy is an examination of skin neoplasms for malignancy using a special device. This study is very simple. It takes only a few minutes - and the doctor will be able to examine in detail the structure and other characteristics of a dubious formation. This method is used by specialists of the Republican Dermatovenerologic Dispensary when examining patients with moles.

The desire to part with moles in a person arises only for very good reasons for him. Firstly, for aesthetic reasons, when due to the presence of moles in certain places, the patient begins to experience self-doubt.

Very often, moles that rub and cling to clothes, are damaged during shaving and interfere with walking are also removed: along the gate line, under the hair, etc. This is especially true for large convex moles, damage to which is highly undesirable.

If good quality is not in doubt, the removal of moles on the face and body can be done by any of the methods available today. It is possible to verify the absence of abnormal cells only on the basis of a dermoscopic examination. Therefore, before removal, it is necessary to consult a dermatologist or oncodermatologist. Based on the study, the method and depth of influence on the neoplasm are also determined. After removal of the mole, a histological analysis of the excised tissues is performed. To date, there are the following ways to remove moles: surgical, cryodestruction (removal of moles with nitrogen), electrocoagulation, as well as using a CO2 laser. The right method of treatment guarantees the best result, so the removal of moles on the face and body should be trusted to professionals.

Removal of moles with a laser.

Despite the variety of different methods of treatment, laser removal of moles is recognized as the most effective of modern methods. Due to the adjustable depth of exposure and the small diameter of the laser beam, it works very precisely, with minimal damage to surrounding tissues. This is important when removing moles, for example, on the face and other visible areas.

Laser removal of moles is performed under local anesthesia, with the help of modern lasers, the surface of the mole is gradually treated, evaporating one layer after another. High accuracy is provided by the ability to control the diameter of the beam and the depth of exposure.

Laser mole removal has a number of advantages:

100% removal after the first procedure.

Rapid healing (5-7 days).

No bleeding.

Low percentage of possible complications (pigmentation, scars and scars after removal of moles).

Laser removal of moles is an absolutely painless method that takes a few minutes, provided that it is performed by a qualified specialist. Removal of moles is a responsible step, so they need to be removed in specialized clinics by competent specialists.

4.4 How to sunbathe properly so as not to harm the skin.

Summer is the time to relax and have a pleasant time on the beach near various types of reservoirs. Under the influence of direct sunlight, our skin receives a lot of not only beneficial enzymes, but also negative ones. How to avoid a large number of ultraviolet and infrared rays that dry out the skin, provoke premature aging of cells, and contribute to burns? To do this, you need to sunbathe correctly.

It is known that the most dangerous sun in the period from 12 to 14 hours, when its rays are directed almost perpendicular to the surface of the Earth. At this time, it is better to stay indoors or lace shade (shadow cast by trees, bushes, umbrellas). It is recommended to be in the sun until 11 am or after 3 days, and be sure to apply sunscreen to the body.

You can not sunbathe on the first day for a long time. It is best to gradually increase the amount of time you spend in the sun. 2 hours per day is the maximum allowable time.

Sunscreen should not be neglected.

The effectiveness of a sunscreen is primarily determined by the level of sun protection it provides. This is reported by the abbreviation SPF (sun protection factor - sun protection factor), which is necessarily indicated on the packaging. The degree of protection varies from 2 to 100 units. This index indicates how long a safe exposure to the sun will last. That is, by treating the skin with a cream with a sun protection factor of 15, you can be sure that within 75 minutes you will not be in danger of sunburn. If the SPF index is 30 units, then the estimated time increases to 125 minutes. If the product is not resistant to water, then after each entry into the water it will need to be applied again.

Modern sunscreens must be labeled UVA/UVB, which indicates protection against both types of rays (ultraviolet A rays and B rays).

If there are many moles on the body, sunbathing is not recommended at all.

Vitamin-forming effect of ultraviolet rays on the human body.

Sunlight is a powerful therapeutic and prophylactic agent, extremely important for maintaining health. No wonder the old proverb says: "Where the sun rarely looks, there the doctor often comes." The effect of magical ultraviolet rays on the body varies and depends on the wavelength. Some of them have a vitamin-forming effect - they contribute to the formation of vitamin D in the skin. The vitamin-forming effect of ultraviolet radiation is primarily associated with its effect on the synthesis of vitamin D (calciferol). The presence of this vitamin is necessary to maintain a constant level of calcium in the blood. With a lack of calcium in the blood, it is “sucked out” from the bone tissue, leading to its deformation, osteoporosis. Children may develop a well-known disease - rickets, which later leads to severe skeletal deformities and other adverse consequences. To prevent such consequences, it is necessary to satisfy the physiological need of the body for vitamin D. It is 20-30 micrograms per day. However, it is difficult to provide it only through food, since even in the main dietary sources of vitamin D it is relatively small. The Sun, its Ultraviolet component, can help in this situation. It turns out that the sebum secreted by the surface layer of the skin contains a chemical precursor of vitamin D. Under the influence of ultraviolet radiation, it is converted into vitamin D, compensating for its “undersupply” from food.

Lack of sunlight shortens life, scientists from the Medical College (USA) are sure. They conducted a major review of the latest research, thanks to which it became clear that people with the lowest concentration of vitamin D in their blood are at risk of dying earlier than others. The risk of early death for them is higher by 26%. According to scientists, a lack of vitamin D contributes to a rise in blood pressure, disrupts sugar metabolism, and causes a tendency to obesity.

Also, residents of large cities need to remember that polluted air and smog reduce the amount of sunlight that is necessary for the formation of the "Vitamin of the Sun", that is, vitamin D. Therefore, city children in the summer should be more outside the city, where there is clean fresh air and more sun.

6. Disinfectant (bactericidal) action of the sun.

Many microorganisms surround man. There are useful ones that live on the skin, mucous membranes and in the intestines. They help digest food, participate in the synthesis of vitamins and protect the body from pathogenic microorganisms. And there are a lot of them too. Many diseases are caused by the activity of bacteria in the human body. Bactericidal action is the ability to destroy the cell wall of bacteria and thereby cause their death.

Have a bactericidal effect:

ultraviolet rays, radioactive radiation.

antiseptic and disinfectant chemicals, for example: chlorine, iodine, acids, alcohols, phenols and others.

chemotherapeutic drugs of antibacterial action for oral administration.

UV rays increase the body's resistance to infectious and viral diseases. The percentage of antibodies in the blood increases. The formation of antibodies gives the body additional strength to resist viral diseases such as chickenpox, rubella and smallpox. Experiments carried out on a large scale in factories and schools have shown that UV rays can reduce by one third the possibility of getting sick with influenza, colds and rheumatism.

This irradiation has a detrimental effect on most types of pathogenic bacteria, on many viruses and fungi, and therefore is widely used for air disinfection in operating rooms and other hospital premises, as well as in medical practice.

7. The sun is the main source of human joy.

Since the origins of human civilization, the role and significance of the Sun has attracted special attention of people. The population of all ancient communities deified the Sun, gave it miraculous properties.

A study conducted by scientists from the Medical School showed that sunbathing is not only not harmful, but also beneficial, as this activity prolongs our life. By reducing the risk of acquiring heart disease and diabetes, the sun's rays allow you to live longer and stay healthy, scientists say. But the same scientists warn that the sun should be dosed and should not be abused.

In addition to the above, the sun's rays stimulate the production of special substances - endorphins, which raise the level of mood and generally have a positive effect on the emotional state. Deficiency of natural solar radiation (due to climatic conditions, age, various diseases, forced long stay in enclosed spaces) is associated with adverse consequences. It adversely affects the general well-being of a person, his neuropsychic tone, reduces mental and physical performance, resistance to infectious and other diseases, increases the risk of fractures and other lesions of the musculoskeletal system, slows down recovery and recovery processes.

8. Practical part. Conducting a survey among the population on the subject of their attitude to the sun, knowledge of means of protection against the harmful effects of ultraviolet radiation and

After analyzing the literature, having studied the materials on the computer, I decided to find out what information our population has regarding solar effects on the human body. To do this, I compiled a small questionnaire, and offered to answer my questions to others. The survey involved 30 people aged 12 to 76 years. And here's what came out of it:

The diagram shows that 90% of respondents believe that the sun's rays are good for the body, and only 10% percent (3 people) believe that the sun is harmful to the body.

The diagram shows that 20% of respondents have heard about such tools and use them. And 80% have heard, but do not use.

The survey revealed that the majority of respondents do not know what sun protection factor (SPF) is and what function it performs.

It can be seen from the diagram that most of the respondents are aware of the harmful effects of the sun and the possibility of the formation of malignant diseases on the skin.

It can be seen from the diagram that only one respondent visits the doctor regularly (once a year) and shows him his moles.

Despite the fact that everyone tans and has a positive attitude towards tanning, not all respondents understand that tanning, as a skin reaction to ultraviolet radiation, is useful in a limited amount, and an excess of solar ultraviolet radiation is just as dangerous as solarium radiation.

Contradictions in understanding the benefits and harms of solar insolation on the human body were also revealed. On the one hand, the respondents believe that ultraviolet radiation is harmful to the human body, and on the other hand, that it is not harmful, but even beneficial. But the majority of respondents could not say what is the benefit or harm of the sun.

Also, not everyone understands the need to use sunscreen in the summer and have absolutely no idea what a sun factor is and why it is needed.

And the majority of the population rarely seek medical advice before sunbathing.

9. Conclusion:

In the course of my practical work, I learned about the positive and negative effects of ultraviolet rays on the human body. I developed a questionnaire and conducted a survey, and after analyzing it, I concluded that the population is not sufficiently informed about the dangers and benefits of ultraviolet rays.

Although ultraviolet rays in a reasonable amount have a beneficial effect on the human body (promote the formation of vitamin D in the skin, affect calciphosphorus metabolism, as well as the nervous processes in the human body). At the same time, if you neglect the rules of sunbathing, the harmful effect of ultraviolet rays on the human body increases.

The paper considers preventive measures to protect the skin from the adverse effects of the sun, as well as ways to eliminate this effect. I also found out that if you deprive yourself of ultraviolet radiation, this also leads to various diseases - from a general decrease in immunity (in adults) to rickets (in children).

Given the low level of education of our population, I believe that my work will be of interest to others. We need to tell people more about this and it is better to start from an early age. The sooner the child learns this, the less harm the sun will do to him, and he will receive only health from solar radiation.

10. List of references.

"Internal Diseases" F.V. Kurdybailo; B.I. Shulutko; N.N. Shastin; V.N. Shestakov; A.N. Shishkin; S.A. Boldueva; THEM. Skipsky.

"Guide to skin diseases" edited by Yu.K. Skripkin.

"Great Soviet Encyclopedia".

Mizun Yu.G., Mizun P.G. Space and health. - M Knowledge, 1984;

Mizun Yu.G., Mizun P.G. Magnetic storms and health. - M., 1990;

Mizun Yu.G. Processes in the biosphere. - M.: Knowledge, 1988

Medical geography and health: Sat. scientific tr. L.: Nauka, 1989;

Moiseeva N.I., Lyubetsky R.E. Influence of helio-geophysical factors on the human body. - L .: Nauka, 1986.

Pleshakova, Kryuchkov "The world around 4th grade".

The sun radiates its energy in all wavelengths, but in different ways. Approximately 44% of the radiation energy is in the visible part of the spectrum, and the maximum corresponds to the yellow-green color. About 48% of the energy lost by the Sun is carried away by infrared rays of the near and far range. Gamma rays, X-rays, ultraviolet and radio radiation account for only about 8%.

The visible part of solar radiation, when studied with the help of spectrum-analyzing instruments, turns out to be inhomogeneous - absorption lines are observed in the spectrum, first described by J. Fraunhofer in 1814. These lines arise when photons of certain wavelengths are absorbed by atoms of various chemical elements in the upper, relatively cold, layers of the Sun's atmosphere. Spectral analysis makes it possible to obtain information about the composition of the Sun, since a certain set of spectral lines characterizes a chemical element extremely accurately. So, for example, with the help of observations of the spectrum of the Sun, the discovery of helium was predicted, which was isolated on Earth later.

In the course of observations, scientists found that the Sun is a powerful source of radio emission. Radio waves penetrate into interplanetary space, which are emitted by the chromosphere (centimeter waves) and the corona (decimeter and meter waves). The radio emission of the Sun has two components - constant and variable (bursts, "noise storms"). During strong solar flares, the radio emission from the Sun increases thousands and even millions of times compared to the radio emission from the quiet Sun. This radio emission has a non-thermal nature.

X-rays come mainly from the upper layers of the chromosphere and the corona. The radiation is especially strong during the years of maximum solar activity.

The sun emits not only light, heat and all other types of electromagnetic radiation. It is also a source of a constant flow of particles - corpuscles. Neutrinos, electrons, protons, alpha particles, and heavier atomic nuclei all together make up the corpuscular radiation of the Sun. A significant part of this radiation is a more or less continuous outflow of plasma - the solar wind, which is a continuation of the outer layers of the solar atmosphere - the solar corona. Against the background of this constantly blowing plasma wind, individual regions on the Sun are sources of more directed, enhanced, so-called corpuscular flows. Most likely, they are associated with special regions of the solar corona - coronary holes, and also, possibly, with long-lived active regions on the Sun. Finally, the most powerful short-term particle fluxes, mainly electrons and protons, are associated with solar flares. As a result of the most powerful flashes, particles can acquire velocities that make up a significant fraction of the speed of light. Particles with such high energies are called solar cosmic rays.

Solar corpuscular radiation has a strong influence on the Earth, and above all on the upper layers of its atmosphere and magnetic field, causing many geophysical phenomena. The magnetosphere and the Earth's atmosphere protect us from the harmful effects of solar radiation.

Speaking about the influence of the sun on the human body, it is impossible to accurately determine the harm or benefit it brings. The sun's rays are like kilocalories from food.. Their deficiency leads to malnutrition, and in excess they cause obesity. So it is in this situation. In moderate amounts, solar radiation has a beneficial effect on the body, while an excess of ultraviolet radiation provokes burns and the development of numerous diseases. Let's take a closer look.

Solar radiation: general effect on the body

Solar radiation is a combination of ultraviolet and infrared waves.. Each of these components affects the body in its own way.

Influence of infrared radiation:

1. The main feature of infrared rays is the thermal effect they create. Warming up the body contributes to the expansion of blood vessels and the normalization of blood circulation.
2. Warming up has a relaxing effect on the muscles, providing a slight anti-inflammatory and analgesic effect.
3. Under the influence of heat, metabolism increases, the processes of assimilation of biologically active components are normalized.
4. Infrared radiation from the sun stimulates the brain and visual apparatus.
5. Thanks to solar radiation, the biological rhythms of the body are synchronized, sleep and wakefulness modes are launched.
6. Treatment with solar heat improves the condition of the skin, relieving acne.
7. Warm light uplifts the mood and improves the emotional background of a person.
8. And according to recent studies, it also improves the quality of sperm in men.

Despite all the debate about the negative effects of ultraviolet radiation on the body, its lack can lead to serious health problems. It is one of the vital factors of existence. And in conditions of ultraviolet deficiency in the body, the following changes begin to occur:

1. First of all, immunity weakens. This is caused by a violation of the absorption of vitamins and minerals, a malfunction in metabolism at the cellular level.
2. There is a tendency to develop new or exacerbate chronic diseases, most often occurring with complications.
3. Lethargy, chronic fatigue syndrome are noted, the level of working capacity decreases.
4. The lack of ultraviolet light for children interferes with the production of vitamin D and provokes a decrease in growth.

However, you need to understand that excessive solar activity will not benefit the body!

Sunbathing contraindications

Despite all the benefits of sunlight for the body, not everyone can afford to enjoy the warm rays. Contraindications include:

• acute inflammatory processes;
• tumors, regardless of their location;
• progressive tuberculosis;
• angina pectoris, ischemic disease;
• endocrine pathologies;
• damage to the nervous system;
• dysfunction of the thyroid and adrenal glands;
• diabetes;
• mastopathy;
• uterine fibroids;
• pregnancy;
• recovery period after surgery.

In all cases, active radiation will aggravate the course of the disease, provoking the development of new complications..

Do not get involved in the sun and the elderly, infants. For these categories of the population, treatment with sunlight in the shade is indicated. The necessary dose of safe heat will be enough there.

Stories from our readers

Vladimir
61 years old

The negative influence of the sun

The time of exposure to infrared and ultraviolet waves must be strictly limited. In excess solar radiation:

• can provoke a deterioration in the general condition of the body (the so-called heat stroke due to overheating);
• negatively affects the skin, causing permanent changes;
• impairs vision;
• provokes hormonal disruptions in the body;
• can provoke the development of allergic reactions.

So that hours of lying on the beach during periods of maximum solar activity cause enormous damage to the body.

To get the necessary portion of light, a twenty-minute walk on a sunny day is enough.

The effect of the sun on the skin

Excessive solar radiation leads to serious skin problems. In the short term, you risk getting a burn or dermatitis. This is the smallest problem you can face when you get carried away with a tan on a hot day. If such a situation is repeated with enviable regularity, the radiation of the sun will be the impetus for the formation of malignant formations on the skin, melanoma.

In addition, UV exposure dries out the skin, making it thinner and more sensitive. And constant exposure to direct rays accelerates the aging process, provoking the appearance of early wrinkles.

In order to protect yourself from the negative effects of solar radiation, it is enough to follow simple safety measures:

1. Be sure to use sunscreen in the summer? Apply it to all exposed areas of the body, including the face, arms, legs and décolleté. The SPF badge on the packaging is the same UV protection. And its degree will depend on the number indicated near the abbreviation. For going to the store, cosmetics with an SPF 15 or SPF 20 level are suitable. If you plan to spend time on the beach, use special products with higher rates. For children's skin, a cream with a maximum protection of SPF 50 is suitable.
2. If you need to be outdoors for a long time at maximum intensity of sunlight, wear clothes made of light fabrics with long sleeves. Be sure to wear a wide-brimmed hat to hide the delicate skin of your face.
3. Control the duration of sunbathing. The recommended time is 15-20 minutes. If you are outside for a longer time, try to get some shade from the direct sunlight.

And remember that in the summer, solar radiation affects the skin at any time of the day, with the exception of night hours. You may not feel the obvious warmth from infrared waves, but the ultraviolet remains high in activity, both in the morning and in the afternoon.

Negative effect on vision

The influence of sunlight on the visual apparatus is enormous. After all, thanks to light rays, we receive information about the world around us. Artificial lighting to some extent can become an alternative to natural light, but in conditions of reading and writing with a lamp, eye strain increases.

Speaking about the negative impact on a person and vision of sunlight, it means damage to the eyes during prolonged exposure to the sun without sunglasses.

Of the unpleasant sensations that you may encounter, one can single out cutting pains in the eyes, their redness, photophobia. The most serious lesion is a retinal burn.. It is also possible dry skin of the eyelids, the formation of small wrinkles.

1. Wear sunglasses. When buying, first of all, pay attention to the degree of protection. Image models often slightly obscure the light, but do not prevent the penetration of ultraviolet radiation. Therefore, it is recommended to put aside a bright frame and opt for quality lenses.
2. Make sure that direct rays do not fall on your face. Stay in the shade, wear a hat, cap or other headgear with a visor.
3. Don't look at the sun. If you do not experience discomfort, this does not indicate the safety of this undertaking. Even the winter sun has enough activity to provide vision problems.

Is there a safe time of year

The use of solar radiation as a health treatment is a common practice. That ultraviolet, that heat belongs to the category of strong irritants. And abuse of these benefits can earn serious problems.

Sunburn is the production of melanin. And to be more precise, the protective reaction of the skin to an irritant.

Is the radiation of the sun so dangerous at any time of the year? It is difficult to give a definite answer to this question. Everything will depend not so much on the season as on the geographical location. So, in the middle latitudes, the activity of solar radiation increases by 25-35% in the summer. Therefore, the recommendations regarding staying outside on a clear day apply only to the hot season. In winter, residents of these regions are not threatened by ultraviolet radiation.

But the inhabitants of the equator face direct sunlight all year round. Therefore, the likelihood of a negative impact on the body is present both in summer and in winter. The inhabitants of the northern latitudes in this regard were more fortunate. After all, with distance from the equator, the angle of incidence of the sun's rays on the earth changes, and with it the radiation activity. The length of the thermal wave increases, and at the same time the amount of heat decreases (energy loss). Hence the winter all year round, as the surface of the earth does not have enough heat to warm up.

Solar radiation is a friend of our body. But do not abuse this friendship. Otherwise, the consequences can be the most serious. Just enjoy the warmth without forgetting the precautions.