» Hyperkeratosis and acne
» Comedogenic cosmetics and acne
» Subcutaneous demodex mite
» Propionibacterium acnes and Propionibacterium granulosum
» Irritated skin and acne
» Heredity and acne
» Nutrition and acne
» Medicines and acne
» Steroids and acne

Types of acne

Read also

Retinoids

Types of retinoids

Read also

Eyelash care

Eyelash growth products

Prostaglandins for the growth of long eyelashes

List of prostaglandins

We analyze eyelash growth products by ingredients

Read also

Anti-aging (anti-aging)

Structure and main functions of human skin

Human skin renewal period

Skin is a fabric: elastic, porous, durable, waterproof, antibacterial, sensitive, which can maintain thermal balance, protect against the harmful effects of the external environment, secrete fat, ensure the safety of the skin, produce odorous substances and recover (regenerate), as well as absorb some necessary chemical elements and reject others, providing protection to our body from the adverse effects of sunlight.

The pH of human skin is 3.8-5.6.

There are approximately 5 million hairs on the surface of human skin. For every square centimeter of human skin there are on average 100 pores and 200 receptors.

What layers of skin can cosmetics affect?

Since cosmetics (cosmeceutical products) can penetrate deeply, can cosmetics reach the dermis?

According to the laws of most countries, a cosmetic product can only have external effects. This means that no cosmetic additives should reach or affect the living layers of the skin. Cosmetic preparations can and must interact only with dead substances of the skin and under no circumstances should they reach its living layers and, moreover, affect them. This is the purpose of cosmetics.

However, in the lower part of the epidermis there is no “block” that prevents the penetration of substances into the depths of the dermis (into the blood and lymphatic vessels). The presence of an effective exchange between the epidermis and dermis is confirmed by experimental data. Substances that have crossed the transepidermal barrier, with a certain degree of probability, enter the blood and, accordingly, are able to affect all tissues of the body.

What substances are able to penetrate deep into the skin, overcome the transepidermal barrier and enter the dermis?

It has been proven that the following penetrate deep into the skin: nicatine, caffeine, nitroglycerin, essential oils (they are enhancers, they are found in the bloodstream), Vit E is retained at the junction of the epidermis and dermis, hylauronic acid reaches the dermis within 30 minutes after application, and then enters into the blood (source: Journal of Investigative Dermatology). Scientists from the University of Rochester Medical Center have concluded that nanoparticles contained in sunscreens penetrate deep into the skin. Liposomes are nanoparticles that easily penetrate into the deep layers of the skin and deliver the necessary nutrients there.

Skin Structure

The secret of the amazing versatility of the skin lies in its structure. The skin consists of 3 important layers:

• 1. Outer layer - epidermis,
• 2. Inner layer - dermis,
• 3. Subcutaneous base – hypodermis.

Each layer performs a specific function.

In different parts of the body, the thickness and color of the skin, the number of sweat, sebaceous glands, hair follicles and nerves are not the same.

It is believed that the thickness of the skin is only a few millimeters, but if the skin constantly needs protection, then it becomes thicker, this is a protective mechanism that everyone has. Therefore, in some places the skin is thicker, in others thinner. The soles and palms have a denser epidermis and a layer of keratin.

As for hairiness, for example, there are many hair follicles on the top of the head, but not a single one on the soles. The tips of the fingers and toes contain many nerves and are extremely sensitive to touch.

Structure and properties of human skin: Epidermis

The epidermis is the upper stratum corneum of the skin, which is formed by stratified epithelium. In the deep layers of the epidermis, cells are alive, where they divide and gradually move towards the outer surface of the skin. The skin cells themselves die and turn into horny scales, which peel off and are removed from its surface.

The epidermis is practically impermeable to water and solutions based on it. Fat-soluble substances penetrate the epidermis better due to the fact that cell membranes contain a large amount of fat and these substances seem to “dissolve” in the cell membranes.

There are no blood vessels in the epidermis; its nutrition occurs due to the diffusion of tissue fluid from the underlying layer of the dermis. Intercellular fluid is a mixture of lymph and blood plasma flowing from the terminal loops of capillaries and returning to the lymphatic and circulatory systems under the influence of heart contractions.

What cells does the epidermis consist of?

Most epidermal cells produce keratin. These cells are called keratinocytes (spinous, basal and granular). Keratinocytes are in constant motion. Young keratinocytes are born when the germ cells of the basement membrane, located at the border of the epidermis and dermis, divide. As the keratinocyte matures, it moves to the upper layers, first to the stratum spinosum, then to the granular layer. At the same time, keratin, a particularly strong protein, is synthesized and accumulated in the cell.

Eventually, the keratinocyte loses its nucleus and major organelles and turns into a flat “sac” filled with keratin. From this moment on, it receives a new name - “corneocyte”. Corneocytes are flat scales that form the stratum corneum (survived epidermal cells), responsible for the barrier function of the epidermis.

The corneocyte continues to move upward and, having reached the surface of the skin, exfoliates. A new one takes his place. Typically, the life span of a keratinocyte lasts 2-4 weeks. In childhood, the process of renewal of epidermal cells is more active, and slows down with age.

Corneocytes are held together by plastic “cement”, consisting of a double layer of special lipids - ceramides (ceramides). Molecules ceramides (ceramides) and phospholipids have hydrophilic “heads” (fragments that love water) and lipophilic “tails” (fragments that prefer fats).

Melanocytes are found in the basal layer of the skin (basement membrane) and produce melanin. These are the cells that produce the pigment melanin, which gives the skin its color. Thanks to melanin, the skin protects a person to a significant extent from radiation: infrared rays are completely blocked by the skin, ultraviolet rays are only partially blocked. In some cases, the formation of age spots depends on the condition of the basement membrane.

There are also special ones in the epidermis Langerhans cells, which perform the function of protection against foreign bodies and microbes.

What is the thickness of the epidermis?

The thickness of the epidermis is approximately 0.07 - 0.12 millimeters (this is the thickness of a plastic film or paper sheet); the particularly rough skin of our body can reach a thickness of 2 mm.

The thickness of the epidermis is heterogeneous: it is different in different places of the skin. The thickest epidermis, with a pronounced keratinizing layer, is located on the soles, a little thinner on the palms, and even thinner on the genitals and skin of the eyelids.

How many days does it take for the epidermis to completely renew itself?

The appearance of the skin, its freshness and color depend on the condition of the epidermis. The epidermis consists of dead cells, which are replaced by new ones. Thanks to the constant renewal of cells, we lose about 10 billion cells per day, this is a continuous process. Over the course of our lives, we shed about 18 kilograms of skin with dead cells.

When the skin exfoliates, it is cleansed - this is a necessary process of skin renewal, in which, along with dead cells, all substances harmful to the skin are removed: the cells take with them dust, microbes, substances secreted by the sweat glands (along with sweat, urea, acetone, bile pigments, salts, toxic substances, ammonia, etc.). and much more. The skin prevents the army of microbes from reaching us: within 24 hours, our skin is attacked per 1 cm from 100 thousand to several million of all kinds of microbes. However, if the skin is healthy, it becomes impenetrable to them.

The younger and healthier the skin, the more intense the process of its renewal occurs. New cells push out old ones, old ones are washed away after we shower, wash, sleep, and put on clothes. With age, cell renewal occurs less and less often, the skin begins to age, and wrinkles appear.

The epidermis is separated from the dermis by a basement membrane (it consists of elastin and collagen fibers) with a germinal layer of continuously dividing cells, which gradually move from the basement membrane to the surface of the skin, where they then peel and fall off. The epidermis is completely renewed, exactly replaced by a completely new layer: a mole remains a mole, dimples remain dimples, freckles remain freckles, cells accurately reproduce at the genetic level what the skin should look like in accordance with the individual characteristics of each individual person.

The process of cell movement from the basement membrane to peeling and falling off the surface of the skin at a young age is 21-28 days, and then occurs less and less frequently. Starting around the age of 25, the skin renewal process becomes slower and increases to 35-45 days by the age of 40 and 56-72 days after the age of 50. This is precisely the reason for the use of anti-aging and restorative drugs for a period of at least a month, and for older people - at least 2-3 months.

The process of division and advancement of mature skin cells is not only slower, but also heterogeneous in different areas, which also affects the aesthetic appearance of the skin. If dead skin cells become layered, the process of cell division occurs more slowly, leading to faster skin aging. In addition, the layer of dead cells makes it difficult for oxygen and nutrients to penetrate the skin.

How many layers does the epidermis contain?

The epidermis consists of 12-15 layers of the stratum corneum. However, depending on the structure, the epidermis can be divided into five main zones (layers): basal, spinous, granular, shiny and horny. The upper (outer) layer of the epidermis consists of dead cells without nuclei, while the inner layer consists of living cells that are still capable of dividing.

Fragments of the horny, lucid and granular layers, which do not have the ability to divide, can be classified as dead skin structures, and, accordingly, the boundary between “living and dead” substances should be located somewhere in the spinous layer.

1. Basal layer of the epidermis (germinal)

The basal layer is the inner layer of the epidermis closest to the dermis. It consists of prismatic single-row epithelium and a large number of slit-like spaces.

The bulk of cells here are keratinocytes containing chromatin and melanin.

Between the basal keratinocytes are melanocytes containing huge amounts of melanin. Melanin is formed in these cells from tyrosine in the presence of copper ions. This process is regulated by the melanocyte-stimulating hormone of the pituitary gland, as well as catecholamines: adrenaline and norepinephrine; thyroxine, triiodothyronine and androgens. Melatonin synthesis increases when the skin is exposed to ultraviolet radiation. Vitamin C plays a significant role in the synthesis of melanin.

Among the cells of the basal epithelium there are few specific tactile cells (Merkel cells). They are larger in size than keratinocytes and contain osmiophilic granules.

The basal layer provides attachment of the epidermis to the underlying skin and contains cambial epithelial elements.

2. The spinous layer of the epidermis (stratum spinosum)

Above the basal layer is the spinous one (stratum spinosum). In this layer, keratinocytes are located in several layers.

The cells of the stratum spinosum are large, their shape is irregular, gradually becoming flattened as they approach the granular layer. The cells of the stratum spinosum contain spines at the sites of intercellular contacts.

In the cytoplasm of spinous cells there are keratinosomes - granules containing lipids - ceramides. Cells of the spinous layer secrete ceramides, which, in turn, fill the space between the cells in the overlying layers. Thus, the stratified squamous keratinizing epithelium becomes impermeable to various substances.

In addition, there are desmosomes - specialized cell structures.

Keratinocytes in the stratum spinosum contain very little chromatin, so they are paler. They have one peculiarity: in their cytoplasm there are many special thin tonofibrils.

3. Granular layer of the epidermis (stratum granulosum)

The granular (keratohyaline) layer (stratum granulosum) consists of spinous keratinocytes and branched epidermocytes. It is assumed that these cells are “wandering” epidermal macrophages that perform a protective function.

In the granular layer there are from 1-3 on the palms and 5-7 on the soles layers of flat cells, closely adjacent to each other. Their oval nuclei are poor in chromatin. A peculiarity of the cells of the granular layer is the peculiar grains in their cytoplasm, consisting of a substance similar in structure to DNA.

There are two main types of granules located in the cytoplasm of granular layer cells: keratoglian and lamellar. The former are necessary for the formation of keratin, and the latter ensure the skin's moisture resistance by releasing special lipid molecules onto its surface.

4. Shiny (eleidine, transparent) layer of the epidermis (stratum lucidum)

The shiny layer (stratum lucidum) is located above the granular one. This layer is quite thin and is clearly visible only in those areas where the epidermis is most pronounced - on the skin of the palms and soles.

It is not found on all areas of the skin, but only where the thickness of the epidermis is significant (palms and soles), and is completely absent on the face. Consists of 1-3 rows of flat cells, most of which do not contain nuclei.

Flat, homogeneous keratinocytes are the main cellular elements of this layer. The shiny layer is essentially a transition from living epithelial cells to keratinized scales located on the very surface of human skin.

5. The stratum corneum of the epidermis

The stratum corneum is the layer of the epidermis in direct contact with the external environment.

Its thickness varies in different areas of the skin, and quite significantly. The most developed stratum corneum is on the palms and soles, much thinner on the abdomen, flexor surfaces of the arms and legs, sides, eyelid skin and genitals.

The stratum corneum contains only thin, anucleate cells that fit tightly together. Horny scales consist of keratin, a substance of albuminoid nature that contains an abundance of sulfur but little water. The scales of the stratum corneum are tightly connected to each other and provide a mechanical barrier for microorganisms.

Structure and properties of human skin: Dermis

The dermis is the inner layer of skin, the thickness of which ranges from 0.5 to 5 mm, the greatest on the back, shoulders, and hips.

The dermis contains hair follicles (from which hair grows), as well as a huge number of tiny blood and lymphatic vessels that provide nutrition to the skin; contraction and relaxation of the blood vessels allows the skin to retain heat (thermoregulatory function). The dermis contains pain and sensory receptors and nerves (which branch into all layers of the skin and are responsible for its sensitivity).

The dermis also contains functional glands of the skin, through which excess water and salts are removed (excretory function): sudoriferous (produce sweat) and sebaceous (produce sebum). The sebaceous glands produce the necessary amount of sebum, which protects the skin from aggressive external influences: it makes the skin waterproof, bactericidal (sebum, together with sweat, creates an acidic environment on the surface of the skin, which has an adverse effect on microorganisms). Sweat glands help maintain a constant body temperature, preventing overheating, by cooling the skin by secreting sweat.

How many layers does the dermis contain?

The dermis includes two layers: the reticular and papillary layers.

The reticular layer consists of loose connective tissue. This tissue includes an extracellular matrix (we'll talk about it in more detail below) and cellular elements.

The papillary layer extends into the epidermis and forms the dermal papillae. These papillae create a special, unique “pattern” of our skin and are especially visible on the balls of our feet and the soles of our feet. It is the papillary layer that is responsible for the “fingerprints”!

The basis of cells in the dermis is fibroblast, which synthesizes extracellular matrix, including collagen, hyaluronic acid and elastin.

Extracellular matrix, what is it and what does it consist of?

The absorption of the extracellular matrix includes two main components: the fibrillar part and the matrix.

Fibrillar part- These are collagen, elastin, and reticulin fibers that create the skin frame. Collagen fibers intertwine with each other, thus creating an elastic network. This network is located almost on the surface of the skin under the epidermis and forms a skeleton that gives the skin strength and elasticity.

In the facial area, collagen fibers create a special dense network. The collagen fibers in it are so strictly arranged and ordered that they form lines of least stretch. They are known as Langer lines. They are known to cosmetologists and massage therapists: using Langer's lines they massage the face and apply any cosmetics. This is done in order not to load the skin, not to stretch it, thus provoking the formation of wrinkles.

In youth, the collagen fiber frame is strong and is able to provide mobility and flexibility to the skin, maintaining its elasticity and shape. Unfortunately, our female age is short...

I really liked the comparison of the leather with a Soviet bed, which is based on a metal mesh. The iron springs of the new bed quickly return to their original position, but under load the springs of the frame begin to sag and soon our bed loses its shape. Our skin also works - young springs (collagen fibers) keep their shape perfectly, but with age they sag and become flabby. No matter how great a mattress we style on the surface, it will not solve our problem.

Matrix (matrix or amorphous component) its structure resembles a gel and consists of polysaccharides. The best known polysaccharides are chitosan, seaweed polysaccharides, and hyaluronic acid.

It is the components of the extracellular matrix, both amorphous and fibrillar, that create the skin from the inside. The saccharides themselves do not form fibers, but they fill all the spaces between the connective cells and fibers. It is through them that the interstitial transport of all substances occurs.

As a result, it is the condition of the dermis (water content in the polysaccharide gel, the integrity of collagen fibers, etc.) that determines the condition of the epidermis and the healthy appearance of the skin.

Structure and properties of human skin: Hypodermis (subcutaneous fatty tissue)

The hypodermis is the subcutaneous base (fat layer), protects our body from excess heat and cold (allows us to retain heat inside us), serving as a thermal insulator, softens falls from impacts.

Subcutaneous fatty tissue is a reservoir of vitamins

Fat cells are also depots in which fat-soluble vitamins (A, E, F, K) can be stored.

Less fat - more wrinkles

Subcutaneous fatty tissue is very important as a mechanical support for the outer layers of the skin. Skin in which this layer is weakly expressed usually has more wrinkles and folds and ages faster.

The more fat, the more estrogen

An important function of adipose tissue is hormone production. Adipose tissue is capable of accumulating estrogens and can even stimulate their synthesis (production). Thus, you can get into a vicious circle: the more subcutaneous fat we have, the more estrogen is produced. This is especially dangerous for men, since estrogenic hormones suppress their androgen production, which can lead to the development of hypogonadism. This leads to a deterioration in the functioning of the sex glands and leads to a decrease in the production of male sex hormones.

It is very important for us to know that adipose tissue cells contain a special enzyme - aromatase. It is with its help that the process of estrogen synthesis by adipose tissue is carried out. Guess where the most active aromatase is located? That's right, in the fatty tissue on the hips and buttocks!

What is responsible for our appetite and feeling of fullness?

Our adipose tissue contains another very interesting substance - leptin. Leptin is a unique hormone that is responsible for the feeling of satiety. Leptin allows our body to regulate appetite and, through it, the amount of fat in subcutaneous tissue.

After all, our appearance and how others perceive us depend on its condition. 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 when the skin is exposed to 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, a killer mole is blue-black or dark brown in color, 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 environmental influences, 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, is a 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 with a gauze napkin. 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.

● Honey mask. Mix honey (2 tablespoons) with 2 tablespoons of flour and 1 egg white for 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 of lemon and 3 drops of 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 those who suffered from acne as a teenager, which is an indicator of high testosterone activity in the body, were 33% less likely to have a heart attack. 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.

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

© Science Photo Library

10. In humans an average of 100,000 hairs per head. People with blond hair have 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

© Kwangmoozaa/Getty Images Pro

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

© Science Photo Library

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.

© Science Photo Library

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 of the world. 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.

© Cristian Negroni

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.

© Povozniuk/Getty Images

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.

© master2 / Getty Images Pro

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 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.

© Brainsil1

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.

The outer layer of the epidermis, called stratum corneum, consists of corneocytes - dead cells that do not have nuclei.

In more detail, human skin consists of three layers:

The top layer is the epidermis;

The middle layer is the dermis;

The bottom layer is the hypodermis.

The epidermis interests people most of all in everyday life, because it is the main factor in protecting the skin from dehydration, the development of bacterial background and other unpleasant factors. It is this layer of skin that can change depending on the influence of certain cosmetic procedures on it. The epidermis is divided into several layers:

Basal layer;

Layer spinosum;

Granular layer;

Shiny layer;

The stratum corneum is the outermost layer of the epidermis.

Epidermal cells go through a huge number of biochemical changes and perform various functions, although most of them are technically dead cells.

Types of active epidermal cells

There are four types of active epidermal cells:

Melanocytes. They are pigment cells located at the junction of the dermis and epidermis. Melanocytes give the skin its color and are responsible for tanning;

Langerhans cells. They are functional cells immune system, capable of detecting foreign agents and pathogenic flora that have entered the epidermis;

Merkel cells. They are tactile cells and are responsible for sensitivity;

Basal cells. They produce new cells epidermis. Basal cells are located at the junction of the dermis and epidermis.

Skin renewal process

Epidermal cells begin their existence as living cells in the basal layer. The basal layer is also called the germinal layer.

This layer consists of small cells lined up in a row and resembling a cylinder in shape. During the biological process of basal cell division, which is called mitotic division, the formation of new cells identical to the basal cells occurs.

Fresh cells are pushed upward due to the mitotic division that occurs, after which they begin to move towards the outer skin surface. The closer the cells become to the outer surface of the skin, the more keratin they accumulate. Thus, by the end of its journey to the outer surface of the skin, the cell loses its main organelles and nucleus, but accumulates a large amount of keratin. This process is called keratinization or keratinization.

Types of keratin

There are two types of keratin in cells:

The first type of keratin. It is found in hair and epidermal skin cells and is a soft keratin. This keratin is quite flexible and soft structure;

The second type of keratin. It is a tough keratin found in fingernails and toenails. This keratin has solid structure.

The main tasks of the skin keratinization process are the following:

Strengthening the resistance of the skin surface to water;

Resistance to the appearance of bacterial microflora and foreign substances on the skin;

Protecting skin from dehydration and dryness.

Structure of the epidermis

As cells move toward the outer surface of the skin, they pass through several layers within the epidermis, undergoing a series of biochemical changes. When moving from the basal layer to the skin surface, the cells increase in size and begin the process of alignment, due to which the spinous cell layer is formed. Further, from this layer, the cells continue to move upward, then form a granular cell layer, where the cells appear granular in shape due to their filling with keratin. After the granular layer, the cells form the stratum lucidum, in which they lose their own nuclei and some organelles. The last and outermost layer of the epidermis is called the stratum corneum because its cells, when viewed under a microscope, resemble the tile roof of a house.

All cells passing through keratinization process, are called keratinocytes - that is, cells that have undergone keratinization. This term is general to describe epidermal cells of any layer and stage of the keratinization process. Keratinocytes that reach the outermost, stratum corneum of the skin are called corneocytes, or dead cells.

A good analogy for the process of keratinization of skin cells is the transformation of grapes into raisins. Basal cells are associated here with ripe grapes; they are just as round, dense and fresh. Next, the grapes begin to dry out, and their structure actively loses moisture and becomes hard. Raisins are associated with corneocytes, the dried out, flatter cells that stack like tiles on the surface of a residential roof.

Human skin thickness

Skin thickness a person depends on a specific bodily area, as well as on individual and age characteristics. The average thickness of human skin ranges from 0.5 to 5 millimeters, excluding subcutaneous fat. Humans have the thickest skin on soles of feet, and the thinnest skin is located on human centuries. The skin is thinnest in childhood and old age, while in adults the skin is denser.

Layers of skin

Human skin consists of three layers:

Epidermis. Its thickness in different parts of the body can vary from 0.05 to 1.5 millimeters. There is no blood in the epidermis, so after a skin injury, blood can only flow if the epidermis and dermis are damaged and pass through them. The most dense skin is on the feet and palms, the least dense is on the eyelids;

Dermis. Its thickness ranges from 0.3 to 3 millimeters. The thickness of the dermis can vary markedly from person to person in the same body areas. This information must be taken into account before skin resurfacing and medium peels;

Hypodermis, or subcutaneous fat. Its thickness ranges from 2 millimeters in the skull area to 10 centimeters or more in the buttock area. The hypodermis is thickest on the posterior and extensor surfaces of the limbs. Hypodermis is absent in humans under the nail plates, on the eyelids and in some areas of the genital organs.

Useful article?

Save so you don't lose!

Article navigation

Leather- This is one of the human organs that perform a protective role and a number of biological functions. Skin covers the entire human body, and depending on height and weight, its area ranges from 1.5 to 2 m2, and its weight ranges from 4 to 6% of a person’s weight (excluding the hypodermis).

The article examines the structure of human skin, its structure and functions of each layer, how skin cells are formed and renewed and how they die.

Skin functions

Main purpose of skin- This is, of course, protection from external environmental influences. But our skin is multifunctional and complex and takes part in a number of biological processes occurring in the body.

Main functions of the skin:

• mechanical protection- the skin prevents soft tissues from mechanical stress, radiation, microbes and bacteria, and the entry of foreign bodies into the tissues.
• UV protection- under the influence of solar treatment, melanin is formed in the skin as a protective reaction to external adverse effects (during prolonged exposure to the sun). Melanin causes the skin to become temporarily darker in color. A temporary increase in the amount of melanin in the skin increases its ability to block ultraviolet radiation (retains more than 90% of radiation) and helps neutralize free radicals formed in the skin when exposed to the sun (acts as an antioxidant).

• thermoregulation- participates in the process of maintaining a constant temperature of the whole body, due to the work of the sweat glands and the thermal insulating properties of the layer hypodermis consisting mainly of adipose tissue.
• tactile sensations- due to nerve endings and various receptors located close to the surface of the skin, a person feels the influence of the external environment in the form of tactile sensations (touch), and also perceives temperature changes.
• maintaining water balance- through the skin, the body, if necessary, can secrete up to 3 liters of fluid per day through the sweat glands.
• metabolic processes- through the skin, the body partially removes by-products of its vital activity (urea, acetone, bile pigments, salts, toxic substances, ammonia, etc.). The body is also capable of absorbing some biological elements from the environment (microelements, vitamins, etc.), including oxygen (2% of the body’s total gas exchange).
• vitamin synthesisD- under the influence of ultraviolet radiation (sun), vitamin D is synthesized in the inner layers of the skin, which is subsequently absorbed by the body for its needs.

Skin structure

The skin consists of three main layers:

• epidermis(epidermis)
• dermis(corium)
• hypodermis(subcutis) or subcutaneous fat tissue

In turn, each layer of skin consists of its own individual structures and cells. Let's look at the structure of each layer in more detail.

Epidermis

Epidermis- This is the top layer of skin, formed mainly on the basis of the protein keratin and consisting of five layers:

• horny- the uppermost layer, consists of several layers of keratinized epithelial cells called corneocytes (horny plates), which contain insoluble protein keratin
• brilliant- consists of 3-4 rows of cells, elongated in shape, with an irregular geometric contour, containing eleidin, from which it is subsequently formed keratin
• grainy- consists of 2-3 rows of cells of a cylindrical or cubic shape, and closer to the surface of the skin - diamond-shaped
• spiny- consists of 3-6 rows spinous keratinocytes, polygonal shape
• basal- the lowest layer of the epidermis, consists of 1 row of cells called basal keratinocytes and having a cylindrical shape.

The epidermis does not contain blood vessels, so the intake nutrients from the inner layers of the skin to the epidermis is happening due to diffusion(penetration of one substance into another) fabric(intercellular) liquids from the dermis layer into the layers of the epidermis.

Intercellular fluid is a mixture of lymph and blood plasma. It fills the space between cells. Tissue fluid enters the intercellular space from the terminal loops of blood capillaries. There is a constant exchange of substances between tissue fluid and the circulatory system. Blood delivers nutrients into the intercellular space and removes cell waste products through the lymphatic system.

The thickness of the epidermis is approximately 0.07 - 0.12 mm, which is equal to the thickness of a simple sheet of paper.

In some areas of the body, the thickness of the epidermis is slightly thicker and can be up to 2 mm. The most developed stratum corneum is on the palms and soles, much thinner on the abdomen, flexor surfaces of the arms and legs, sides, eyelid skin and genitals.

Skin acidity pH is 3.8-5.6.

How do human skin cells grow?

In the basal layer of the epidermis Cell division occurs, their growth and subsequent movement to the outer stratum corneum. As the cell matures and approaches the stratum corneum, the protein keratin accumulates in it. Cells lose their nucleus and major organelles, turning into a “sac” filled with keratin. As a result, the cells die and form the uppermost layer of skin from keratinized scales. These scales shed over time from the surface of the skin and are replaced by new cells.

The entire process from the birth of a cell to its exfoliation from the surface of the skin takes an average of 2-4 weeks.

Skin permeability

The scales that make up the uppermost layer of the epidermis are called - corneocytes. The scales of the stratum corneum (corneocytes) are connected to each other by lipids consisting of ceramides and phospholipids. Due to the lipid layer, the stratum corneum is practically impermeable to aqueous solutions, but solutions based on fat-soluble substances are able to penetrate through it.

Color of the skin

Cells inside the basal layer melanocytes, which highlight melanin- a substance on which skin color depends. Melanin is formed from tyrosine in presence of copper ions and vitamin C, under the control of hormones secreted by the pituitary gland. The more melanin contained in one cell, the darker the color of a person's skin. The higher the melanin content in the cell, the better the skin protects from exposure to ultraviolet radiation.

With intense exposure to ultraviolet radiation on the skin, the production of melanin in the skin sharply increases, which provides the skin with a tan.

The effect of cosmetics on the skin

All cosmetics and procedures, intended for skin care, act mainly only on the top layer of skin - epidermis.

Dermis

Dermis- This is the inner layer of skin, with a thickness of 0.5 to 5 mm depending on the part of the body. The dermis is made up of living cells, is supplied with blood and lymphatic vessels, contains hair follicles, sweat glands, various receptors and nerve endings. The basis of cells in the dermis is fibroplast, which synthesizes the extracellular matrix, including collagen, hyaluronic acid and elastin.

The dermis consists of two layers:

• reticulate(pars reticularis) - extends from the base of the papillary layer to the subcutaneous fatty tissue. Its structure is formed mainly from bundles of thick collagen fibers, located parallel to the surface of the skin. The mesh layer contains lymphatic and blood vessels, hair follicles, nerve endings, glands, elastic, collagen and other fibers. This layer provides the skin with firmness and elasticity.
• papillary (pars papillaris), consisting of an amorphous structureless substance and thin connective tissue (collagen, elastic and reticular) fibers forming papillae lying between the epithelial ridges of spinous cells.

Hypodermis (subcutaneous fat tissue)

Hypodermis- this is a layer consisting mainly of adipose tissue, which acts as a heat insulator, protecting the body from temperature changes.

The hypodermis accumulates nutrients necessary for skin cells, including fat-soluble vitamins (A, E, F, K).

The thickness of the hypodermis varies from 2 mm (on the skull) to 10 cm or more (on the buttocks).

Cellulite occurs during inflammatory processes in the hypodermis that occur during certain diseases.

Video: Skin structure

• The area of ​​the entire skin of an adult is 1.5 - 2 m2
• One square centimeter of skin contains:

• more than 6 million cells
• up to 250 glands, of which 200 sweat and 50 sebaceous
• 500 different receptors
• 2 meters of blood capillaries
• up to 20 hair follicles

• Under active load or high external temperature, the skin through the sweat glands can secrete more than 3 liters of sweat per day
• Thanks to the constant renewal of cells, we lose about 10 billion cells per day, this is a continuous process. During our lifetime, we shed about 18 kilograms of skin with dead cells.

Skin cells and their function

The skin is made up of a large number of different cells. To understand the processes occurring in the skin, it is good to have a general understanding of the cells themselves. Let's look at what different structures are responsible for (organelles) in a cage:

• cell nucleus- contains hereditary information in the form of DNA molecules. In the nucleus, replication occurs - doubling (multiplying) of DNA molecules and the synthesis of RNA molecules on a DNA molecule.
• core shell- ensures the exchange of substances between the cytoplasm and the cell nucleus
• cell nucleolus- it synthesizes ribosomal RNA and ribosomes

• cytoplasm- a semi-liquid substance that fills the internal space of the cell. Cellular metabolic processes occur in the cytoplasm
• ribosomes- necessary for the synthesis of proteins from amino acids according to a given matrix based on genetic information embedded in RNA (ribonucleic acid)
• vesicle- small structures (containers) inside the cell in which nutrients are stored or transported
• Golgi apparatus (complex)- this is a complex structure that is involved in the synthesis, modification, accumulation, and sorting of various substances inside the cell. It also performs the functions of transporting substances synthesized in the cell through the cell membrane and beyond its boundaries.
• mitochondria- the energy station of the cell, in which the oxidation of organic compounds occurs and the release of energy during their decay. Generates electrical energy in the human body. An important component of the cell, changes in the activity of which over time lead to aging of the body.
• lysosomes- necessary for the digestion of nutrients inside the cell
• intercellular fluid filling the space between cells and containing nutrients