What is the color of a person's skin called? What determines the color of the skin of people. Why does everyone have a different shade

Health

1. Skin - largest organ in the human body

2. If you stretch the skin of an average person, it will cover an area of 2 square meters

3. Skin is about 15 percent of your body weight.

4. There are two types of skin: hairy and hairless

5. Your skin has three layers:

Epidermis - water repellent and dead layer

Dermis - hair and sweat glands

Subcutaneous fat - fat and large blood vessels

6. Every inch of your skin has a certain elasticity and strength, depending on the location. So the skin on the knuckles is different from the skin on the stomach.

7. Scar tissue lacks hair and sweat glands

8. The thinnest skin on your eyelids - about 0.2 mm

9. The thickest skin on your feet - about 1.4 mm

10. In humans an average of 100,000 head hairs. Blonde hair has about 140,000 hairs, dark hair has 110,000, and redheads have about 90,000.

11. Each hair has a small muscle that lifts the hair in cold and various emotional states.

12. Body hair grow 2 to 6 years

13. We lose 20 to 100 hairs a day

14. Keratin forms the outer dead layer of the skin and nails.

15. More 50 percent of the dust in the house is made up of dead skin

16. Every 28 days your skin is renewed.

17. Lipids are natural fats that keep the outer layer of skin hydrated and healthy. Detergents and alcohol destroy lipids.

18. Skin sheds over 30,000 dead cells every minute.

19. As we age, we begin to shed less skin. In children, old cells are shed faster. This is why babies have such a pink fresh complexion

20. The skin produces about 500 ml of sweat per day.

21. Sweat itself is odorless, and it is thanks to bacteria that body odor is produced.

22. Your skin is a microcosm in which more than 1000 species of bacteria live and about 1 billion individual bacteria.

23. The glands that produce earwax are special sweat glands.

24. On average, you live between your toes about 14 types of fungus.

Melanin pigment and human skin color

25. Skin color is the result of a protein called melanin. Huge skin cells in the form of tentacles - melanocytes, produce and distribute the pigment melanin.

26. People have the same number of melanin cells. Different skin color is the result of their activity, not quantity.

27. Human skin varies greatly in different parts of the world. According to the well-known classification - the Lushan scale, there is 36 basic types of human skin color.

28. 1 in 110,000 people is albino that is, it does not have melanin cells.

29. Melanin is also responsible for eye color, and itself the skin covering the eye is transparent and very sensitive.

30. Permanent skin color in a child is formed within about 6 months.

Acne and skin treatment

31. The cause of acne or pimples is the overproduction of cells that line the sweat glands.

32. Even babies suffer from acne. Some newborns develop acne in the first few weeks of life. The cause of acne in newborns is not fully known, but it does not require treatment and goes away on its own.

33. About 80 percent or 4 out of 5 teenagers experience acne.

34. But this is not only a problem of adolescence. One in 20 women and one in 100 men suffers from acne in adulthood

35. The appearance of a boil is associated with a staphylococcal bacterium. It penetrates into tiny cuts in the skin, getting into the hair follicles.

Appearance of human skin

36. Type and texture of the skin talking about your health. With illness, the skin turns pale, and with fatigue, bags under the eyes appear.

37. Smoking negatively affects the condition of the skin, depriving it of oxygen and nutrients, slowing down blood flow, and also contributing to the appearance of wrinkles.

38. Skin heals very quickly. Since the top layer of the skin is a living tissue, the body begins to heal the wound immediately. Blood from a cut forms a scab and seals the wound.

39. Most moles are genetically predetermined even before we were born.

40. People who have more moles on their bodies live longer and look younger those who have fewer moles.

41. Almost every person has at least one mole.

42. Moles can appear anywhere including genitals, scalp and tongue.

43. Freckles most often appear in people with fair skin color.

44. Freckles fade in winter since melanin is not produced in large quantities during the winter months.

45. Freckles can be red, yellow, light brown and dark brown.

46. Unlike moles, freckles do not appear at birth, they appear after a person has been exposed to sunlight.

47. Vitamin A heals skin from sun damage and cellulite

48. Vitamin D- reduces rashes and neoplasms

49. Vitamin C– antioxidant, restores vitamin E and protects from the sun

50. Vitamin E- Antioxidant, protects against sun damage and aging.

What is the difference between people living on our planet? To answer this question is not so - it's really difficult. Of course, physique, religion, race, gender, worldview, temperament and, most importantly, skin color. It can be white, black, swarthy, have a reddish tint.

What is it connected with?

Let's start with the fact that people with a certain skin color could be found only in certain areas of our planet. Redskins - in America, blacks - in the countries of the African continent, whites - in Europe. In this case, we are talking about the territories in which their ancestors lived, since in the modern world, thanks to the migration process, people with different skin colors can be found anywhere.

Of course, the place of residence left its mark on the skin color of the people living there. Climate features, solar activity, zoning - all these factors, one way or another, affect the amount of melanin produced by special cells of the human body - melanocytes. But the color of human skin depends on the amount of melanin in the epidermis. The more of this pigment, the darker the skin.

But back to the territory of residence, and how it affects the production of melanin. Let's take a simple example. The body of a person sunbathing in the sun acquires a swarthy hue. This is because under the influence of sunlight, melanocytes begin to produce more melanin, which makes the skin darker. That is why people living in hot countries can have black skin. The thing is that they spend a lot of time in the sun, and their epidermis is maximally saturated with melanin. That's the whole secret of black skin.

In white people, melanin is either completely absent or contained in minimal amounts. Hence, the color of their skin can be white or have a pinkish tint, which is due to the presence of a large number of blood vessels in the skin. So, for example, albinos have not only completely white skin and hair of the same color, but also a completely colorless iris.

And yet, what role does melanin play in the human body?

As it turns out, its main function is to protect the skin from ultraviolet solar radiation. It is no secret that a person who has received an increased dose of solar radiation is at risk of developing skin cancer. Melanin, in this case, is a protective filter. It makes the skin swarthy, and thereby changes its reflective ability. It turns out that dark skin is less susceptible to ultraviolet rays.

But how, after all, did dark-skinned and white-skinned people appear?

The body of an ancient man was covered with a thick layer of wool, which protected his skin from ultraviolet sunlight. In the process of evolution, the hair on the human body began to disappear. Why this happened is not known for certain. One way or another, their skin was unprotected from solar radiation.

People living in hot countries were at particular risk. Representatives with swarthy and dark skin turned out to be in a more advantageous position. It was they who were able to survive in such extreme conditions. There was a real natural selection, as a result of which the Negroid race appeared.

The exact opposite situation occurred in people with white skin. They lived in cold northern regions, with a small amount of ultraviolet radiation. With its deficiency, human bones become brittle, and beriberi occurs in the body. Under such conditions, only people with lighter skin, which is able to absorb more ultraviolet radiation, could exist. They then replaced dark-skinned people whose skin blocked ultraviolet rays. For this reason, their offspring suffered from rickets, and the bones could not withstand the load and broke. As a result, only fair-skinned people, whom we call white-skinned, could survive in these places.

We will be enlightened further =). Since skin color has been analyzed, today there is some scientifically popular information about skin color. Consider combinatorics and genetics.
Information used
http://halibi.livejournal.com/231820.html#cutid4

Skin color depends on three elements - melanin (saturation, brown), hemoglobin (reddish tint) and carotene (yellowish tint). Each person has their own combination of these three elements, which gives a unique skin tone. In men, the skin is slightly darker - the hormonal background also affects. The skin on different parts of the body is colored unevenly.

The darkness of the skin depends on melanin. Two genes are responsible for the production of melanin, each of which carries two characteristics - dominant and recessive. Dominant characteristic - black skin, recessive - white. But this does not mean that one constantly dominates - they mix. Therefore, 16 combinations are possible.

Let the first gene be labeled with the number 1, and the second - with the number 2. The dominant characteristic of black skin color will be M, and the recessive characteristic of white skin color will be m.

Let's decipher the picture

1 - M1M1M2M2 - all dominant characteristics - Black skin

2. MMMm - three dominant and one recessive characteristic - Dark brown skin.

3.MMmm - two dominant and two recessive characteristics - medium brown leather .

4. Mmmm - one dominant and three recessive characteristics - light brown skin color

5. mmmm - all characteristics are recessive - white skin color

There are transitional combinations between them.

If you wish, you can calculate what skin saturation your children can have if you are friends with combinatorics. Just like that - just for fun.
my type Mmmm, my husband's type Mmmm. We can pass on two genes to a child. I got several combinations. Of these, a little MMMm , a little Mmmm, and mostly Mmmm. Everything is predictable with us. =) The lightest skin color can be like mine, the darkest - like my husband's. And it happens much more interesting - when the child is darker or lighter than both parents.

Carotene and hemoglobin determine the dominant skin tone (semitone) - either pink (hemoglobin) (top line of the picture) or yellowish (carotene) (bottom line of the picture)

Usually these semitones are taken into account by the manufacturers of tonal means, but this will be a separate topic.

Anthropologists often use the Von Luschan scale to describe skin color. (Von Luschan Chromatic Scale)
To find out the color of your skin, look at the skin under the forearm, which usually does not tan.

Here is the natural version of the scale

Here is a more convenient digital

I can't determine exactly my skin type - either 15 or 16. I can only say that it is clearly beige, i.e. not 14, and obviously not olive, i.e. not 17. 16 seems closer, because the skin is a little yellowish on the hands - but the color may depend on the monitor settings ..

Skin saturation is closely related to phototype - the reaction of the skin to ultraviolet light. I will talk about this next time.

Why do some people have lighter skin color than others? Scientists sought to prove the difference by examining human evolution over tens of thousands of years. Everyone knows that people with darker skin protect themselves better who live closer to the equator from the intense radiation of the sun. But a new study of ancient DNA concludes that the color of Europeans has continued to change over the past 5,000 years, suggesting that additional factors, including diet and sex drive, may play a role.

Human skin color depends on evolution

Homo sapiens, modern humans, first appeared in Africa about 200,000 years ago, and researchers have speculated that the first humans were dark-skinned Africans like today because dark skin is more advantageous in Africa. Dark skin has higher levels of the pigment melanin, which blocks UV and protects it from dangers such as DNA damage - which can lead to skin cancer - and the breakdown of vitamins A and B. On the other hand, skin cells need exposure to a certain amount of UV light to in order to produce vitamin D.

These competing dependencies mean that as soon as primitive people moved away from the equator, their outer cover began to lighten.

Recent studies, however, have suggested that the picture is not so simple. First, a number of genes control the synthesis of melanin (which itself comes in two different forms in the human body), and each gene appears to have a different evolutionary history. In addition, everything manifested itself after the ancient people migrated from Africa to Europe starting about 40,000 years ago. The scientists looked at variants of four pigmentation genes in modern Portuguese and African populations and calculated that at least three of them evolved strongly tens of thousands of years after the migration from Africa. Another group of scientists sequentially examined the genome of an 8,000-year-old male hunter-gatherer skeleton found at the site of La Brana Arinterro in Spain and found that the outer coat was dark but with blue eyes - again indicating that natural selection came into play relatively late in prehistory. .

DNA studies on the composition of melanin

To get a better idea of how Europeans' skin pigmentation changed over time, a team of geneticists at University College London extracted DNA from 63 skeletons previously found at archaeological sites in present-day Ukraine and nearby areas. The researchers were able to isolate three genes associated with pigmentation from 48 skeletons ranging in age from 4,000 to 6,500 years. The TYR gene, which is involved in melanin synthesis, the SLC45A2 gene, which helps control the distribution of pigment enzymes in skin cells, and the HERC2 gene, the main gene that determines whether the iris is brown or blue. These three genes, like all pigmentation genes, are found in numerous variants that result in different skin tones, hair, and eye colors.

By comparing variants of these ancient skeletal genes with modern humans living in these areas, as well as a larger sample of modern genes, the scientists found a significant increase in the frequency of variants associated with lighter skin and hair, as well as blue eyes, between ancient and modern populations. For example, contemporary Russians and Ukrainians living in those areas have, on average, more than eight times fair skin and four times as many blue-eyed variants.

Thus, prehistoric Russians and Ukrainians seem to have undergone comparatively fair skin and hair and a higher frequency of blue eyes while their ancestors left Africa.

To further test this conclusion, the team of scientists showed computer simulations designed to distinguish between natural selection and "genetic drift". These tests of ancient populations have determined the rate at which genetic change occurs and can determine whether there is genetic drift in the modern world. Using ancient DNA, scientists have provided direct evidence for choice in pigmentation.

Natural selection of fair skin

But why did strong natural selection for fair skin, hair, and eye color occur thousands of years after humans migrated from Africa with their harsh UV rays?

With regard to skin color, scientists suggest that these ancient populations previously received a lot of vitamin D from their food, such as vitamin D in fish and animal liver when they were hunter-gatherers. But after the advent of agriculture, when grains such as wheat and barley became a major part of their diet, early Europeans synthesized large amounts of vitamin D into their bodies from these foods. That's when lighting became very beneficial. The study provides evidence that getting regular vitamin D as a result of shifting to a more heavily farmed lifestyle may have caused the evolution of skin lightening.

As well as a tendency to lighten and color hair and blue eyes, scientists also speculate that it may be due to sex drive - something that in evolutionary terms is called sexual selection.

If so, then the originally rare men or women with blond hair and blue eyes would have been more attractive to the opposite sex, and so there would have been more offspring. This kind of sexual preference for humans has been confirmed in other animals.

Of course, in some modern cultures, summer tanning is also considered sexy, and here the study may provide some positive news: Modern tanning options can also turn golden skin like sun exposure.

But the ancient philosophers were absolutely right: everything is known only in comparison. Living without a break on one of their continents for thousands of years, people did not even suspect that their skin color could be completely different. And the first Europeans who set foot on the soil of South America were simply amazed: the red-skinned people fell prostrate before them! The Indians sincerely believed that it was their white-skinned gods who had once flown to heaven. And since that ancient time of the Great Geographical Discoveries, it was the color of human skin that played and continues to play a significant role in the life of society.

What colors are the skin?

Usually, starting to list the names of the color of a person's skin, they first cheerfully bend their fingers: white, black, yellow, red ... And at this they are puzzledly silent. Indeed, how many of these colors are actually, and why are they different for different people, what does it depend on? Anthropologists in their practice, when determining skin color, use the Lushan color scale. These are reference samples, which are a set of opaque glasses. There are only 36 of them: from pinkish-white to completely black.

Thus, "officially" there are 36 shades of different colors. Why do people have different skin colors?

Why the different color?

According to anthropologists, the color of the skin of any person depends on the area in which his distant ancestors lived. It is very possible that the bodies of our ancestors were covered with light patchy skin, the same as that of modern chimpanzees. There is also a theory, confirmed by experiments, of how people developed different skin tones. But for now, it's still just a theory. It is only well established that color is directly dependent on a substance called melanin, which is determined by genes.

The longer a white-skinned person is under the sun, the more melanin is formed, which means that his skin will become darker. Darker skin is better at protecting against UV radiation. Since Africa is considered the cradle of all modern people, the conclusion is clear: those who were better protected from the merciless sun got a better chance of survival. Accordingly, the “start in life” was received by the darkest individuals.

As people settled around the planet, they fell into new, completely different territories in terms of climatic conditions. Much weaker solar radiation in Europe, especially in its North. And if an excess of ultraviolet radiation is detrimental to humans, then its lack is doubly detrimental. Without sunlight, the human body does not produce vitamin D, which is essential for the formation of strong bones. It is clear that light, white skin “absorbs” life-giving light better. That's why people of the North and the South have different skin colors.

Skin: colors or shades?

So what skin colors do humans have? Experts call the main ones: olive, red, golden and neutral. The real, natural skin color of a particular person is most accurately determined near the collarbone, on the neck. And since the skin on the face and hands is always under the influence of the environment, then, accordingly, it can significantly change color.

Olive color includes shades of gray, green and yellow. Red consists of red-brown, red and red-blue shades. And golden - from golden brown, gold and peach tones. Neutral skin color is a natural balance of cold and warm tones. Usually it is called ivory, beige.

All this is the result of the work of three pigments: carotene (yellow), melanin (brown) and hemoglobin (red). And if they talk about normal skin color, then this means that, first of all, a monochromatic skin is meant, that is, evenly colored, without any spots of a different tone.

There are three major human races identified today. Each of them has only her own skin color. Caucasoid race (Europe, North Africa, Western Asia) - light or swarthy color. Mongoloid (Asia, America) - yellowish skin. Negroid (Africa) - dark brown or black skin.

What does genetics say?

Heredity is most clearly manifested in the color or shade of the skin. But the mechanism itself, why the color of hair, eyes, skin is transmitted from parents to their children, has long been a mystery to everyone. There is evidence, confirmed by ancient literature, that the answer to this question was sought at the dawn of human history.

And only in the middle of the 19th century, the scientist Gregor Mendel discovered and formulated the basic laws of heredity. And a hundred years later, already in the middle of the 20th century, experts began to study the very chemical processes that control heredity. The new science was called genetics.

Today, such words as "genetics", "genes" no longer surprise anyone. And just a little over half a century ago, thousands of people died defending the right of this science to exist.

Now every modern high school student will be able to tell quite sensibly about DNA. This deoxyribonucleic acid is a real "gene bank" in which all the physical data of each person is recorded and stored. That is, it is not difficult for scientists to determine how many human genes determine skin color.

A bit of theory

Every cell in our body has two codes: one from the father, the other from the mother. The cell, analyzing this information, forms a combination of those features that will be inherent in only one person.

The DNA molecule is very complex and large. The answer to the question why one and not another sign is formed is not yet completely clear. And although any cell in the body has two sets of DNA, at one stage of the division of the sperm and the egg, they only have one set.

Thus, at the moment of fertilization and formation of the very first cell of the future organism, a set of codes from both parents is laid in it. Statistics have determined that four to eight sets of codes are responsible for skin color.

It is also very interesting that the set of codes in the egg and sperm does not correspond to the code of the grandfather and grandmother.

Genetics against racism

Having proved from a scientific point of view what explains the color of a person's skin and what determines its formation, genetics has put a fat cross on all theories of racism. Seeing people with a different skin color, for various reasons, standing at a lower level of social development, some "scientists" hastened to declare them "second-class" people.

Unfortunately, such "theories" have brought untold suffering and misfortune to millions of people of color. To date, racism, preaching the dominant role of the white race, is rejected by all progressive mankind.

Our skin is a true mystery

The human body is a real storehouse of mysteries and complex problems, the answers to which will have more than one generation to look for.

Even such familiar to us human skin also keeps many unsolved secrets. To date, the veil is ajar only over a very small part of them, while the rest of the clues are yet to come.

Here are some interesting facts.

The largest organ of the human body is the skin.
15 percent of the weight of the whole body falls on the skin, and the area of the skin of an adult is about two square meters.
In all people, the number of melanin cells in the skin is approximately the same. The color determines not the number, but the activity of these cells.
Albinos (such people do not have melanin cells) are one in 110,000.
The same melanin is “responsible” for the color of the eyes.
In a newborn, a permanent skin color will form during the first six months of life.