What determines the thickness of the skin? The structure of facial skin in cosmetology

Older people and children have thinner skin than adults. In children in the first months of life, the average skin thickness is 1 mm; at the age of 3 to 7 years – 1–1.5 mm; from 7 to 14 years – 1.5–2 mm and only by 20–25 years it reaches 3 mm.

The skin in the area of natural openings (nose, mouth, vagina, anus, urethra) passes into the mucous membrane.

The skin consists of 3 layers:

1) upper - epidermal or epidermis;

2) the skin or dermis itself;

3) subcutaneous fat.

The epidermis is represented by stratified squamous keratinizing epithelium. Due to the ability to keratinize, or keratinize, the main cellular element of the epithelium is called a keratinocyte. There are five layers of cells in the epidermis, each of which represents a certain stage of differentiation (development) of keratinocytes.

The deepest layer, the basal or germinal layer, borders the dermis and consists of a single row of cells. In the cytoplasm of the keratinocyte, i.e. intracellularly, there are granules of dark brown or black pigment - melanin. In fair-skinned people, the pigment melanin is found only in the cells of the basal layer. In dark-skinned individuals, it occurs both in the cells of the stratum spinosum and in the stratum corneum. The basal layer also contains melanocytes, which make up about 10–25% of the cells in the basal layer and produce the pigment melanin. The ratio of melanocytes to keratinocytes in the epidermis is 1: 36. Black people and white people have approximately the same number of melanocytes. Melanin is involved in wound healing processes and protects body cells from the damaging effects of ultraviolet radiation.

Among the basal (main) keratinocytes there are tactile cells - Merkel cells (Merkel discs). There are especially many Merkel cells in the basal layer of the fingertips and lips. Langerhans and Greenstein cells, or immune cells, work together to regulate immune responses in the skin. Langerhans cells are capable of phagocytosis: by capturing foreign antigens and holding them on the surface, they provide immunological memory. Langerhans cells can synthesize biologically active substances: γ-interferon, interleukin-1, etc. Langerhans cells secrete met-enkephalin, an endogenous modulator (internal pathogen) of pain and a strong stimulator of the immune system. Above the basal layer is the spinous layer. Then the granular layer is located. On the palms and soles, the granular layer consists of 3–4 rows; in other areas, this layer is represented by 1–2 rows of cells. The cells of the granular layer have lost the ability to divide.

Flattened, anucleate keratinocytes form a stratum lucidum consisting of 3–4 rows of cells. The shiny layer is clearly visible on the skin of the palms, where the epithelium is thick. The cells of the stratum lucidum contain eleidin, glycogen, and oleic acid. The boundaries of the cells of the stratum pellucida are poorly visible.

The nonnuclear outer part of the epidermis is the stratum corneum. The thickest stratum corneum is on the skin of the palms and soles, on the extensor surface of the limbs. Thinner is the stratum corneum on the abdomen, on the flexor surface of the limbs, on the lateral surfaces of the body, especially thin on the skin of the eyelids and external genitalia in men. The stratum corneum is represented by horny plates (scales, corneocytes) - cells that are at the final stage of keratinization (keratinization). The horny plates in the outer part of the epidermis are gradually rejected. This process is called epithelial desquamation. Horny scales come in two types: with loose and dense filling of keratin fibrils (fibers). Loose horny scales are located closer to the granular layer, in them you can find the remains of cellular structures (mitochondria, etc.); these scales are called T cells. Dense horny scales are located superficially. The thickness of the stratum corneum depends on:

1) on the speed of reproduction and movement in the vertical direction of keratinocytes;

2) on the speed of their rejection.

The entire process of skin renewal, i.e., the appearance, differentiation, and maturation of keratinocytes, takes about 26–27 days. The main characteristics of the epidermis are shown in Table 2.

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. Leather is approx. 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 its location. So the skin on your knuckles is different from the skin on your 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 hairs per head. In people with blond hair about 140,000 hairs, dark-haired people have 110,000, and red-haired people 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 we lose from 20 to 100 hairs per day

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

15. More 50 percent of house dust is dead skin

16. Every 28 days your skin renews itself.

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

18. Skin loses more than 30,000 dead cells every minute

19. As we age, we begin to shed skin less often. 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 has no odor, and it is thanks to bacteria that body odor appears.

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 have about 14 types of fungi.

Melanin pigment and human skin color

25. Skin color is the result of the action of a protein called melanin. Huge tentacle-shaped skin cells - melanocytes - produce and distribute the pigment melanin.

26. People have the same number of melanin cells. Different skin colors are a result of their activity, not quantity.

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

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

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

30. A child’s permanent skin color is formed within about 6 months.

Acne and skin treatment

31. The cause of acne or pimples is the excessive production of cells lining the sweat glands.

32. Even kids suffer from acne. Some newborn babies develop acne in the first few weeks of life. The cause of newborn acne 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 suffer from acne in adulthood

35. The appearance of a boil is associated with staphylococcal bacteria. It penetrates tiny cuts in the skin and enters the hair follicles.

Appearance of human skin

36. Skin appearance and texture talks about your health. When you are sick, your skin turns pale, and when you are tired, bags appear under your eyes.

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

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

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

40. People with more moles on their body 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 the genitals, scalp and tongue.

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

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 treats skin damaged by sun exposure 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.

After all, it is on her condition that our appearance and how others perceive us. Especially now, in the summer, when we are not burdened with extra clothes. And in the next issue of our Encyclopedia, you will learn about how to maintain the health of the kidneys - perhaps one of the main filters of our body.

Layer by layer

Skin is the largest organ of our body. It is a barrier between the body and the external environment. However, the skin performs not only a protective function.

Our skin consists of three layers. The topmost one is called the epidermis. Its thickness is no more than 1 mm. It is this thin layer that is the first “outpost” that protects us from adverse external factors. For example, from excess solar radiation. The epidermis contains special pigment cells; in response to ultraviolet radiation, they trigger the production of melanin, which protects us from sunburn.

By the way, the human body receives the bulk of vitamin D through the epidermis. This vitamin is formed under the influence of the skin ultraviolet rays. Vitamin D promotes the body's absorption of calcium and phosphorus and is essential for growth and strong bones. However, tan lovers should know that throughout our life our skin can only protect the body from a certain amount of sunlight. Depending on the skin type, this number varies from 50 to 150 thousand hours. It is in our interests not to exceed this limit.

Below the epidermis is the dermis. This layer of skin is much thicker. Our appearance largely depends on the state of the dermis - if it lacks moisture, vitamins or minerals, wrinkles will appear on the face, and its color will become dull and grayish. Thanks to the huge number of vessels and capillaries, the dermis maintains our body temperature constant. By the way, it is she who is responsible for the appearance of “goosebumps” on the skin. “Pimples” appear due to a sharp narrowing of blood vessels from the cold. And in the heat, the dermis cools us with the help of millions of sweat glands.

The deepest layer of skin is called subcutaneous fat. It protects us from shock and internal damage, cold and heat, and creates an “emergency reserve” for the body in case of an emergency. It contains hair roots and numerous nerve endings. There are 250 thousand cold receptors, 30 thousand heat receptors, a million pain endings, and half a million touch receptors scattered across the entire surface of our skin. Thanks to them, a human finger is able to feel vibrations with an amplitude of two ten-thousandths of a millimeter!

The skin is also an organ of the immune system. At least 182 species of bacteria live on human skin. And their total number reaches 500,000 billion. Moreover, not all of these bacteria are pathogenic. Most of them constitute normal microflora, which protects the body from various diseases.

The structure of the skin of a human finger: 1-5 - epidermis (1 - basal layer, 2 - spinous layer, 3 - granular layer, 4 - shiny layer, 5 - stratum corneum); 6 - excretory duct of the sweat gland; 7-8 - dermis (7 - papillary layer, 8 - reticular layer); 9 - terminal section of the sweat gland; 10 - hypodermis.

Skin in facts and figures

The surface of the skin is on average about 2 square meters.

Skin weight is approximately 16% of body weight.

2460 milliliters of blood passes through the skin in one minute.

Human skin is completely renewed in approximately 28 days.

Together with the lungs, the skin participates in the breathing process. The skin “inhales” 3–4 g of oxygen per day and “exhales” about 9 g of carbon dioxide.

The skin of women who smoke ages four times faster than that of those who do not smoke.

The thickness of the skin of an adult is 2 mm and depends on the area of the body. The thickest skin is on the palms of the hands and soles of the feet, where its thickness can reach 10 mm.

Get lost, mold!

For dermatologists, summer is a “fruitful” time. Heat and humidity are excellent conditions for the formation of abrasions and abrasions on our body, through which many viruses and microbes penetrate into the subcutaneous tissue.

Mycoses. Most often, fungal diseases (mycoses) affect the feet and toes - in a warm and slightly moist environment between the toes and in the skin folds, microorganisms feel especially comfortable.

Source of infection. Fungal spores can lie in wait for your feet on a treadmill or exercise mat in a fitness club, in a swimming pool, in a gym, on the sand that others have walked on, in the shower. Another source of infection is the shoes of a person suffering from mycosis of the feet. For example, home slippers, which he can offer to relatives and friends who come to visit him. You can also become infected with a fungal disease in a store by trying on shoes that others have tried on.

Security measures. Do not wear someone else's tight shoes, do not walk barefoot in public places. For prevention, after visiting a pool or bathhouse, treat your feet with a 2% iodine solution mixed with cologne or 2–5% salicylic alcohol.

Papilloma virus. It's easy to catch warts in the summer. Their appearance is caused by infection with the human papillomavirus. The most common are the familiar vulgar (that is, simple) warts. Plantar and flat ones “sit” on our body a little less often. And they are much more difficult to treat. The first - due to their depth: having formed on the feet and heels, plantar warts often send out strong, painful roots into the skin. The second - due to the large area of the lesion: slightly protruding above the surface of the skin, flat warts are most often localized on the back of the hands, forearms, and face.

Source of infection. The main source of warts is a person or household items that he used. And the main factor predisposing to infection is reduced immunity, as well as increased sweating of the skin of the hands and soles of the potential victim.

Security measures. Avoid microtrauma to the skin (cracks, cuts). If they appear, disinfect the wound as quickly as possible. And do not use other people’s household items, do not walk barefoot where many feet have walked before you. If a wart appears, the only way to say goodbye to it is to lubricate it with special ointments and pastes. Or more radical methods of treatment: electrocoagulation, laser hair removal, freezing with liquid nitrogen.

Streptoderma. In terms of the severity of its manifestations, this infectious disease caused by staphylococcus or streptococcus entering a wound or abrasion cannot be compared with warts. Initially, the areas affected by streptoderma are covered with purulent nodules, turning into honey-yellow crusts, which quickly spread to other parts of the body.

Source of infection. As a rule, it is the sick person himself. After all, streptoderma is a very contagious disease, and therefore you should not hug him and share the same towel.

Security measures. The best thing is to urgently take the victim to a skin and venous dispensary. Self-medication is excluded. Without proper attention, streptoderma develops into deep scarring ulcers with pronounced pain and elevated temperature.

Prepared by Tatiana IZMAILOVA

Sun Mark

Everyone dreams of bringing a beautiful tan back from vacation. And many achieve their dreams, sometimes at the cost of their own health. Fans of tanning run the risk of developing melanoma - a dangerous disease that turns a seemingly banal mole into a time bomb.

Weak spot of the skin. Have you ever thought about what moles are, how they appear on our body and what they are needed for? Experts answer this question very definitely: moles (or nevi) are weak points of our skin, its defect.

There are several factors that contribute to the degeneration of moles and age spots. The main one is the sun. In order to “get” a harmless mole, it is enough to get sunburned at least once.

Under the influence of ultraviolet radiation, the nucleus, the genetic code of the melanocytes that make up the nevus, is affected, and the process of their dying is disrupted. As a result, the “stagnant” cells are degenerated, forming colonies of crazy cells, which can ultimately lead to a tumor process.

Another sure way to get melanoma is through injury. With any damage, a dangerous mole turns into a small “Chernobyl”, releasing a huge number of deadly cells into the blood.

Dangerous decoration. An experienced oncodermatologist can detect incipient melanoma immediately. A change in color, peeling, the appearance of an inflammatory halo around the nevus, its enlargement or thickening, the appearance of cracks, bleeding is an extremely alarming signal for a professional.

As a rule, the killer mole is blue-black or dark brown, with irregular contours. The death generator can be as small as a grain. Giant moles, completely covered with hairs, are also dangerous. If you have such a “decoration”, keep an eye on it! However, there is no clear pattern here. Very small (only 1.5 cm) moles - so-called dysplastic nevi, precursors of melanoma - can also develop into malignant ones. It is not at all necessary that they protrude above the surface of the skin. Both convex and flat moles can pose a threat.

Better delete it! The sooner you remove a potentially dangerous mole, the less likely it is that the process of its degeneration will go too far. Thanks to similar tactics in America and Australia, where a real epidemic of skin cancer has broken out in recent decades, the mortality rate from melanoma has declined.

You yourself can prevent the appearance of melanoma. How? Explore your body! Study the topography (location) of your moles and the moment of birth of new ones. If necessary, resort to the help of loved ones: we don’t have eyes on our backs. If among your moles there are ones that cause concern, don’t wait, run to the doctor!

Prepared by Tatiana YURIEVA

Our information

Representatives of the first and second phototypes - white-skinned, red-haired and blue-eyed - are most at risk of getting a “bad” mole. When traveling to the south, these citizens need to be especially careful and protect themselves from open sunlight. But owners of the third phototype should not relax: the optimal time for tanning is from 9 to 11 am and from 16 to 19 pm.

Away, wrinkles!

For most women, every wrinkle, if not a tragedy,

then at least a reason for frustration. Unfortunately, until scientists have invented the elixir of youth, it is impossible to “cancel” the appearance of new wrinkles. But you can get rid of existing ones.

Cream. The most affordable way to combat wrinkles is to use an anti-aging cream. The main thing is that it is chosen correctly. The choice of cream does not depend on the number of wrinkles. But it is necessary to take into account the type of skin, the location of wrinkles and the age of their “carrier”, so it is advisable to still resort to the help of a professional, and not rely on your own knowledge or the advice of friends. Typically, anti-aging creams contain antioxidants (ascorbic acid, retinol), which protect the skin from harmful effects environment, as well as fruit acids, which have a mild exfoliating effect.

It is usually recommended to start using anti-aging cream at the age of 30, although much depends on the individual characteristics of the skin. True, in most cases, one cream is not enough to smooth out even small wrinkles, and from time to time you have to pay visits to a cosmetologist, whose arsenal also has some other means to “exterminate” folds on the skin.

One of the most popular ways to eliminate wrinkles is dermabrasion, or exfoliation of the top layer of skin using a laser or aluminum chips. Redness on the skin persists for several days after dermabrasion, so many people prefer more gentle procedures.

Myostimulation. This is the effect of electric current on the muscles of the face or body. Under the influence of current, the muscles contract, their blood circulation increases, and the tissues are saturated with oxygen. Depending on the goals you want to achieve, the doctor chooses a special program. Myostimulation allows you to reduce a double chin, sagging cheeks, reduce the number of wrinkles; with this procedure, the skin texture is evened out, elasticity increases, and a reduction in the volume of problem areas is achieved. Sometimes the effect of electric current is combined with the effect of heat. This allows you to increase the efficiency of the procedure.

Ionization. During this procedure, the effect of electric current is combined with the effect of cosmetic preparations. Under the influence of current, these drugs penetrate into the deeper layers of the skin and restore its elasticity. This allows you to eliminate wrinkles on the face and neck, and get clearer body contours.

Injections. Usually, by the age of thirty, the burden of life's problems forces us to constantly wrinkle our foreheads, move our eyebrows, and generally show our dissatisfaction with the world around us through facial expressions. As a result, expression lines appear on the forehead, around the mouth or between the eyebrows. If measures are not taken in time, expression lines will become permanent, or static. You can get rid of them using a substance with the terrible name “botulinum toxin”. If you are not afraid of injections, this is your method. Botulinum toxin is injected under the skin and prevents certain facial muscles from contracting. As a result, no matter how hard you try, you will never be able to move your eyebrows or wrinkle your forehead. This means you won't have facial wrinkles! However, after 6–8 months the effect of botulinum toxin weakens and the injection will have to be repeated.

Surgery. Unfortunately, at a certain age (usually between 50 and 60 years old) the skin becomes sluggish, flabby, scientifically speaking, atonic. Neither anti-aging creams, nor physiotherapy, nor injections will help here. The only way out is plastic surgery or surgical lifting. Naturally, a visit to a cosmetologist is no longer enough, and you will have to go to a plastic surgeon who will tell you how the intervention will be carried out and its consequences.

Acne simple and vulgar

How to get rid of teenage acne? And can summer help with this?

Causes of acne. Acne (or, as doctors say, acne, acne vulgaris) is most often observed in both boys and girls aged 11–17 years during puberty. Previously, it was believed that the face becomes covered with acne due to the increased content of testosterone - the male sex hormone - in the blood. It is found in the body of both men and women. But recent studies have clarified: it’s not the amount of the hormone, but its activity, which leads to increased sebum secretion. And testosterone is overly active in those, for example, who suffered perinatal encephalopathy in infancy and were very restless infants.

Acne also affects those teenagers who do not treat sinusitis, tonsillitis, or teeth, that is, they constantly carry an infection in their body. Acne can be caused by stress, taking hormonal contraceptives, and inherited oily, porous skin.

What to do?

What should poor children covered with acne vulgaris do?

1. Cure a runny nose, if you have one, fill your teeth, don’t be nervous.

2. Eat less food with preservatives, which have a bad effect on the pancreas, worsen the metabolism in the body, causing the skin to suffer. Eat more fresh vegetables and fruits.

3 . In the evening, do not wash oily skin, do not spread infection from pimples across the face, but cleanse it of dust and dirt with lotions for oily skin or rose water. You can boil the petals of one rose flower, cool the broth and wipe the skin with it until the cotton wool is clean.

4 . In the morning it is useful to wash your face with acidified water. In an acidic environment, microbes die. Boiled water should be put in the refrigerator overnight, and in the morning squeeze half a lemon into it per liter of water or acidify it with one or two tbsp. spoons of 4% apple cider vinegar (but not vinegar essence!).

5 . Oily, porous skin must be cleaned. Once or twice a week, while taking a shower, steam your face. Take a washcloth, preferably made from natural materials, pour half a teaspoon of baking soda and half a teaspoon of sea salt on it, which you passed through a coffee grinder twice in advance so that large crystals do not hurt the skin, and thoroughly clean your steamed face with the washcloth. Then be sure to narrow the pores. Take 2 tbsp. spoons of boiled water, 1 tbsp. spoon of apple cider vinegar, 1 tbsp. a spoonful of the simplest cologne, mix everything and wipe the skin with this solution.

6. Do not expose pimples to the hot sun, as the sun causes the infection that lives in the pustules to feel great and multiply quickly. So you need to sunbathe in the morning and in the afternoon, and during the day you need to protect your skin from ultraviolet radiation with special creams. The degree of protection for children and adolescents should be maximum – 60.

7 . But what can be done in the summer to treat acne is to rinse, rinse the skin thoroughly in the sea or in a pool with natural mineral water.

Acne, or acne, – chronic inflammation of the sebaceous glands, mainly of the face, back and chest.

Our information

It is believed that the love of sweets - baked goods, sweets, chocolate - increases the number of teenage acne. In fact, craving for buns is not the root cause of acne growth. This is rather an indicator that the child has disturbances in the functioning of the hormonal system, which is responsible for the appearance of acne. Such children have a very rapid metabolism, it requires a quick replenishment of calories, so they are satisfied with buns.

Marina MATVEEVA

Curdled milk will help

The following procedure will help you cope with enlarged pores and excessive paleness of the skin: apply thick yogurt or fermented baked milk to your face and cover it on top gauze pad. Lie quietly for 10–15 minutes and rinse off the mask with warm water. If your skin is sensitive, then after this procedure redness may appear on your face, which will go away within 20–30 minutes, but in this case you should not make a mask immediately before leaving the house.

What a fruit!

Fruit masks will help get rid of skin problems. What exactly to choose as “raw materials” for home cosmetics depends on what effect you want to achieve.

● Grapes, strawberries, and raspberries moisturize and smooth the skin.

● Bananas and peaches have a softening effect.

● Apricots, zucchini and pumpkin soothe dry, inflamed skin.

● Lingonberries, cherries, currants, and lemon tighten the pores (the juice of another fruit is always added to lemon juice, as it has a very strong effect).

swan neck

The skin on your neck will always look young and elastic if you nourish it with this mask from time to time: mix 1 teaspoon of honey with an egg yolk and 1 teaspoon of butter. Place the mixture on a towel, wrap it around your neck, put oilcloth or cellophane on top and secure the compress with a bandage. After 20 minutes, rinse off the rest of the mixture with warm water and apply nourishing cream to your neck.

Proper nutrition

To keep your skin young, do not forget about nourishing masks.

● Oatmeal mask. Take 2 tablespoons of oatmeal, pour 1/3 cup of hot milk. Apply the warm mixture in a thick layer to your face and neck. The mask perfectly tones the skin, especially in winter period.

● Honey mask. Mix honey (2 tablespoons) with 2 tablespoons of flour and 1 egg white at oily skin or yolk for dry skin. The resulting mass is applied to the face, kept until it dries well, after which it is washed off first with hot and then with cold water. This mask nourishes the skin and improves blood circulation. However, you should not make a honey mask often - once a month is enough. And with vasodilation, it is completely contraindicated.

● Banana mask. Mash 1/4 banana thoroughly, add 0.5 tablespoons of your nourishing cream, 3 drops lemon and 3 drops olive oil. Mix everything well and apply it to your face for 15 minutes. In winter, this mask will provide good skin support. Banana pulp is an excellent natural moisturizer, and its rich vitamin A content is important for dry, irritated skin.

● Apple-carrot. Grate 0.5 carrots and 0.5 apples, add 1 tablespoon of cottage cheese. Mix all ingredients thoroughly and place on your face. Leave on for 15 minutes and then rinse thoroughly. This mask will give your skin a healthy look and improve its elasticity.

The secret of broccoli

Broccoli extract protects the skin from the damaging effects of ultraviolet rays, according to scientists from Johns Hopkins University (USA). According to researchers, the protective effect of broccoli is due to sulforaphane. This substance stimulates the formation of certain proteins in the skin that provide protection against ultraviolet radiation. However, sulforaphane does not absorb sunlight and cannot be used as a substitute for sunscreens.

Sign of a healthy heart

Boys covered in pimples are less likely to die from heart disease in old age. This conclusion was made by scientists from Scotland and New Zealand. It turned out that the likelihood of a heart attack is 33% less among those who adolescence suffered from acne, which is an indicator of high testosterone activity in the body. And these hormones protect the heart in adulthood.

Cell Printer

American scientists have developed a new technique for healing extensive wounds and burns using a “cellular printer”. The device sprays skin cells onto the affected areas of the body using the principle of a color inkjet printer, disinfecting and healing wounds several times faster than what happens with skin transplants.

The “ink” for such a “printer” is a mixture of several types of cells, which researchers obtain from pieces of healthy skin by “melting” it. The “ink” is sprayed layer by layer: first fibroblasts, then keratinocytes, which form the outer skin.

Now the developers are waiting for permission to conduct clinical trials of the “cellular printer” in humans.

Wrinkles are worse than cancer

Fake tanning not only increases the risk of developing melanoma, the most dangerous form of cancer, by 75%, but also leads to the appearance of wrinkles. It is the latter argument, according to American dermatologists, that can influence young tanning salon lovers who do not think about the likelihood of getting skin cancer, but are worried about the appearance of early wrinkles. The fear of becoming unattractive can discourage girls from wanting to sunbathe all year round, experts say.

Chewing gum ages your mouth

The habit of chewing gum leads to the appearance of wrinkles and worsens the lip line, say American dermatologists. Frequent chewing of gum results in “excessive stress” on certain muscle groups, which leads to loss of skin elasticity and leads to wrinkles. Even plastic surgery is sometimes powerless to correct the damage caused by chewing gum.

, deep mycoses and many others. etc.).

As a covering of the body, the skin has a huge receptor field (1.5-2 m2) and at the same time is perfectly integrated into the entire human body. The composition of normal skin includes all tissues, excluding only bone and cartilage (but they can also appear in pathology). The skin is a three-layer system that includes the epidermis (and its appendages), the dermis and subcutaneous fatty tissue (hypodermis). The thickness of the skin is on average 2 mm (from 0.5 to 5 mm). “Active skin” is distinguished - from the surface to the lower border of the superficial choroid plexus. The processes in this zone are to a certain extent independent of the body as a whole. The deeper layers of the dermis perform mainly “support functions.”

Human skin is unique. It is not just a complex covering of the human body. This is a complex system of organs, closely connected with all internal organs person. Despite significant progress in its study, the skin is still an insufficiently studied part of the human body, which creates certain difficulties in understanding the pathological processes in this organ.

The main component of the skin is water (69-73%). However, in terms of the number of functions it performs, it surpasses any other organ.

Let us list the functions of the skin known to us today:

protective;
receptor;
thermoregulatory;
respiratory;
resorptive;
excretory;
exchange;
immune;
endocrine;
cosmetic;
hematopoietic;
communicative;
depositing.

The skin participates in maintaining homeostasis, protects the body from the damaging effects of mechanical, physical, chemical and infectious agents; has the ability to quickly repair damage during the epithelization process.

The epidermis consists of 4 layers: basal, spinous, granular and horny. They represent successive stages of differentiation from the germinal cells of the basal layer to the horny corneocyte. In the epidermis of the palms and soles, between the granular and stratum corneum, there is another layer, the shiny layer. Normally, the epidermis is characterized by a clear demarcation of layers (stratification).

The dermis is the connective tissue base of the skin, in which the appendages of the epidermis, blood and lymphatic vessels, nerves and smooth muscles are located. It consists of 70-80% collagen (mainly types I and III). In the upper parts of the dermis, collagen fibers are thin and randomly located, while in the deeper parts they are coarser and oriented parallel to the surface of the skin. Between the collagen fibers there are a small number of fibroblasts and fibrocytes, which produce collagen. The collagen structures surrounding the skin appendages and blood vessels make up the so-called adventitial dermis. The remaining part of the dermis, consisting of thick bundles of collagen fibers, is the so-called reticular dermis.

The papillary and reticular layers of the dermis are distinguished. The papillary layer lying directly below the epidermis and the part of the reticular layer located below it constitute the upper dermis. The layer of dermis at the level of the pilosebaceous complexes is conventionally designated as the middle dermis, and the underlying layer, containing the sweat glands and bordering the subcutaneous fatty tissue, is called the deep dermis.

Features of the structure of the skin of different parts of the body

In different areas of the skin, the amount of hair, sebaceous and sweat glands, elastic tissue and pigment differs significantly. These features must be taken into account when assessing pathomorphological changes and dictate the mandatory availability of accurate information about the location of the biopsy.

On the skin of the palms and soles, all layers are clearly visible, including the shiny layer that is often absent in other areas. The stratum corneum is especially dense and wide here, the skin papillae are highly developed and uniform; there are a large number of sweat glands, hair and sebaceous glands are absent. The epidermis in these zones has the greatest thickness, which is 0.5-0.8 mm. The dermis is thickest (up to 5.17 mm with an average thickness of 3.3 mm) on the hands, feet, back and buttocks. The papillae of the dermis are most pronounced on the pads of the terminal phalanges of the arms and legs; here they often have a mushroom shape.

On the skin of the face, all layers are indistinct and weakly expressed; the amount of hair and sebaceous glands is significant. In the upper part of the dermis of the facial skin there is a lot of elastic tissue; its fibers are often thickened and can be (especially in the elderly) lump-like and basophilic. In the eyelid area, the thickness of the epidermis is the smallest, it does not exceed 0.06-0.09 mm. The minimum thickness of the dermis (up to 2.64 mm) is also in the eyelid area and, in addition, in the area of the foreskin and labia majora. The dermal papillae are usually shorter here than in other areas of the skin and have the form of nodules or warts.

The scalp contains a large amount of hair, the follicles of which are found in the subcutaneous tissue.

In the skin of the genital organs and breast nipples, a large amount of pigment is found not only in the epidermis, but also in the dermis.

There are free sebaceous glands in the red border of the lips, but no sweat glands. In the skin armpits There are apocrine sweat glands. Sebaceous glands are absent in the skin of the palms and soles.

On the skin of the body, the papillae of the dermis are small, tuberous, club-shaped or horn-shaped, located either separately or severally on one base (compound papilla). Most papillae are nourishing, but there are also sensitive ones.

The subepidermal zone is made of argyrophilic fibers; its border passes at the level of the deepest processes of the epidermis.

Age-related skin features

When assessing the clinical and pathomorphological picture, it is important to consider age characteristics skin in persons over 60 and under 7 years of age. The skin of people over 60 years of age is characterized by a decrease in the thickness of the epidermis (mainly due to the spinous layer), its stratum corneum and subcutaneous fatty tissue. In persons over 70 years of age, these changes are pronounced significantly, and subcutaneous fatty tissue can completely disappear, being replaced by coarse collagen and elastic fibers, among which there are few cellular elements (especially young fibroblasts and histiocytes).

Later, the contours of the epidermis are smoothed out due to sharp atrophy with perinuclear vacuolization of cells, and some glands and hair disappear. The granular layer becomes thinner, and in some places completely disappears. The layer of basal cells loses its palisade-like appearance, and areas of atypical growth with increased melanin content may occur.

The stratum corneum is not only thinner, but also has a looser structure. The number of sweat glands in people over 70 decreases, the membranes of the secretory tubes become sclerotic, undergo degenerative changes, and subsequently the glandular cells disintegrate and are replaced by connective tissue. The sebaceous glands atrophy in the following order (reverse to their development in the embryonic period): small hair-related - medium-sized hair-related - non-hair-related glands. Thinning of the dermis occurs mainly due to the papillary layer, as a result of which the papillae become flattened, up to complete disappearance, and the epidermal-dermal boundary takes on the appearance of a straight line. In addition, the number of cellular elements decreases, also primarily in the papillary layer.

Collagen and elastic fibers of the dermis undergo atrophy (especially in open areas of the skin), and their tinctorial properties also change (basophilia appears). These changes can already be observed in 40-year-olds in the skin of the face, neck and hands.

The number of blood vessels in the dermis decreases. Their walls become sclerotic, and vacuolar degeneration is observed in the cells of the muscle layer. The lumens of arterial vessels become obliterated, while venous vessels, on the contrary, expand. The subepidermal plexus atrophies; in people over 65 years of age, only individual loops remain.

The skin of children under 7 years of age is much thinner than that of adults. At the same age, the papillary layer of the dermis is well expressed only on the palms, soles, dorsum of the hands and feet, lips, skin of the foreskin and labia minora. In other areas it is weakly expressed. The dermis is much richer in cellular elements (especially in the subepidermal layer). Among the cells there are many undifferentiated connective tissue and fat cells.

In the early childhood bundles of collagen fibers, even in the reticular layer, are loose and thin, their contours are unclear.

With age, their number and size increase, their contours become more distinct. In general, in children over 7 years of age, the skin structures are formed and differ slightly from the skin of adults.

In addition, there are some gender differences in skin structure. The thickness of the epidermis and dermis in women is slightly less than in men. Subcutaneous fatty tissue, on the contrary, is thicker in women. The number of sebaceous (especially in the skin of the chin) and sweat glands is greater in men.

Skin (cutis) is an organ that covers the human body, repeating the relief of muscles and bones. The skin is a large receptor field (about 1.6 m2), where there are nerve endings that perceive general irritations (thermal, pain, touch, pressure, vibration). Body temperature and skin respiration are regulated through the blood capillaries of the skin. The skin, forming the general covering of the body, protects the body from the penetration of microbes. The barrier function of the skin also acts against various liquids and gases. The skin contains sweat, sebaceous glands and hair. In addition, derivatives of the skin are nails and mammary glands.

The skin is divided into the epidermis, represented by stratified squamous keratinizing epithelium, and the skin itself (derma), consisting of collagen, elastic, and reticular fibers. The skin itself contains papillary and reticular layers. It contains hair follicles, sebaceous and sweat glands, as well as smooth muscles, pigment and other cells (Fig. 535).

535. Skin structure.
1 - epidermis; 2 - corium; 3 - glandula sebacea; 4 - m. arrectores pilorum; 5 - tela subcutanea; 6 - folliculus pili.

There are also well-developed networks and plexuses of blood and lymphatic vessels. An essential feature is skin color, which depends on the number of pigment cells, which is one of the signs human races. In people of all nationalities, pigmentation is more pronounced in the skin of the nipples of the mammary glands, external genitalia and perineum. The skin of the cheeks, lips, ears, kneecaps and buttocks is reddish in color. Skin in the form of a case covers all parts of the human body, it is elastic and durable. Due to elasticity, when the connective tissue layer of the skin is cut, the edges of the wound diverge. Elastic fibers are located in a certain direction (Fig. 536).

536. Direction of skin lines.

537. Direction of palm skin lines.

The thickness of the skin largely depends on the thickness of the epithelium and connective tissue layer and ranges from 1 to 4 mm. In the thick skin of the sole, palm, and back, both layers are well developed and are inactive. The skin of the face, neck, anterior surface of the torso, genitals and perineum, medial surface of the limbs is thinner, easily mobile, and freely gathers into folds, since subcutaneous tissue consists of loose and fatty connective tissue. During inflammatory processes, large edema can develop in the subcutaneous tissue. Upon external examination, elevations are noted on the skin due to the papillae formed by its connective tissue layer, which fold into ridges. The ridges are clearly visible in the skin of the palms and soles and are characterized by an individual pattern that is constant throughout life (Fig. 537). In other parts of the body, these scallops are less developed. The ducts of the sebaceous and sweat glands open into the grooves between the scallops, so when they come into contact with smooth objects, a pattern of scallops of the fingers and palm remains on them, which is used in forensic practice (fingerprinting). In the skin of the joints, neck, and face there are folds formed by all skin layers. The number of these folds and the depth of the furrows increase with age, which is associated with the destruction of the elastic fibers of the skin, as well as a decrease in its turgor. In older people, the skin atrophies and resembles parchment; it is inelastic and easily folds; deep furrows and wrinkles appear (Fig. 538).

538. Age-related changes in facial relief and skin folds (according to I. Kirpatovsky, V. Bocharov).

The skin itself is connected to the subcutaneous tissue, which consists of loose and adipose tissue. Subcutaneous tissue is a good reservoir of nutrients (fat), and also participates in thermoregulation and protects the body from mechanical damage. In children, women and older people, the subcutaneous fat layer is better developed. Its thickness depends on nutrition, gender, age, professional and national characteristics. The subcutaneous fat layer in women is more pronounced on the hips and in the pelvic girdle (Fig. 539). In men, the subcutaneous fat layer is developed more evenly (Fig. 540). Under the skin everywhere except the face, there is a superficial fascia, which at protruding bony points (spina iliaca anterior superior, trochanter major, acromion, etc.) connects with the periosteum, and in the spina scapulae, the area of the scalp, palms and soles - with aponeuroses. Therefore, in such areas the skin is motionless, and the subcutaneous fatty tissue is divided into cells by connective tissue plates running perpendicularly from the skin to the aponeuroses. Due to this peculiarity of the structure of the subcutaneous connective tissue in the scalp, on the soles and palms, hematomas and exudate during inflammation spread in depth, and not in width, as in other parts of the body.

539. Sexual and individual characteristics deposits of fatty tissue (according to Gritsescu).
1 - fatty tissue is evenly distributed; 2 - fatty tissue is distributed evenly with a slight predominance in the pelvic and shoulder girdle; 3 - fat deposits predominate in the pelvic area.

540. Male external form. Subcutaneous fat is distributed more evenly than in a woman (according to Gritsescu).

In the facial area, facial muscles are woven into the skin, which change the width of the eye, nasal and oral slits, and also form folds, which determines a person’s facial expressions. Systematic contraction of the facial muscles leads to the formation of permanent folds on the face, the pattern of which is especially clearly contoured in the elderly (Fig. 541).

541. Distribution of furrows in the skin of the face and neck in the elderly.

In places of significant friction in the subcutaneous tissue, mucous bursae are isolated, for example, patellar, deltoid, etc., which are adaptive and protective formations.

Embryonic development
The epithelial layer, hair, sweat and sebaceous glands of the skin develop from the ectoderm, the connective tissue base, blood and lymphatic vessels - from the mesenchyme. The epithelial layer is formed at the 5th week intrauterine development, and by the 16th week, keratinization of the epithelium and its desquamation begins. The sebaceous glands begin to function at week 20; their secret permeates the desquamated epithelial cells, forming a fat-like lubricant.

The skin itself develops from connective tissue cells, which form fibrous structures.