Interesting facts about human skin. Human skin: its structure and functions How many layers does the skin consist of?

Human skin plays an important role in the structure of the body, so it is useful for everyone to know interesting facts about human skin. Covering our entire body, the skin performs vital functions to ensure the normal functioning of the human body. The average person is not even aware of some of the amazing properties of skin.

1. Skin is the largest human organ. Its weight can reach 4 kg, and its area is approximately two m2.
2. 66% of indoor dust consists of dead skin cells. Interestingly, our body gets rid of 30 thousand dead cells in one minute. Over the course of a lifetime, the human body produces about 18 kg. skin, and the process of complete renewal occurs approximately a thousand times.

   

3. White skin color appeared relatively recently, about 30-50 thousand years ago. This happened due to the loss of part of the melanin pigment by people who went to the North. There are people who lack this pigment. This phenomenon is called albinism, and is extremely rare - in 1 person per 110 thousand.

   

4. Every person has between 30 and 100 moles on their body.. There are cases when this number reaches 400. There is a hypothesis that those with a large number of moles are less likely to suffer from age-related diseases.

   

5. Women's skin is thinner than men's. This explains why wrinkles appear earlier in women.

   

6. Surprisingly, the most common target for insect bites is the legs.. In addition, scientists have found that a person who has just eaten a banana is more likely to be bitten by a mosquito. In addition, they love to bite fair-haired ones.

   

7. Impossible to tickle yourself, because the cerebellum knows that a person is touching himself with his own hands and simply ignores these actions.

   

8. Sweat glands regulate body temperature. There are two to three million of them. The largest number of sweat glands are found on the palms, soles and forehead. The common myth that sweat has an unpleasant odor is not true. In fact, this smell is produced by microorganisms that live on the human body. These bacteria are most abundant in the armpits. There, their number per cm2 is 80 thousand, compared to 2 thousand on a clean surface.

   

9. Human skin contains a special pigment - melanin.. The content in the body determines its color. If there is a small amount of melanin, a person’s skin is light, and if there is enough pigment in the body, it takes on a darker shade.

   

10. Freckles appear during adolescence and disappear almost completely by the age of 30.. Their presence indicates a lack of melanin in the body.

    

11. Skin smoothness is determined by the state of collagen. In youth, the cells of this protein curl up, allowing the surface of the skin to look smooth and toned. As we age, collagen cells receive less nutrients and become clogged with heavy metals. This leads to their straightening, which lowers skin tone. Collagen consists of 70% dry dermis. Its productivity decreases by 1% annually.

    

12. The outer layer of the epidermis ensures the skin is waterproof. The cells of the epidermis are connected to each other very tightly, and there is a layer of fat on the surface. This layer becomes thinner if the body is exposed to water for a long period. As a result, water penetrates the skin cells and it wrinkles.

    

13. On the feet, the skin thickness reaches up to half a centimeter - this is the area of ​​the roughest skin. And the skin on the eyelids is very thin.

    

14. The sebaceous glands are capable of producing about 20 grams of sebum in 24 hours.. It combines with sweat and creates a special protective skin film that prevents bacterial damage. Different parts of the body have different numbers of sebaceous glands. So, on the back of the hand there are almost no of them, but on the forehead, chin, nose, under the hair, on the chest their number is 400-900 per 1 square centimeter. Pimples and blackheads often form in these areas. The latter indicate clogged pores.

    

15. If there is not enough vitamin D in the human body, spider veins or spider veins form on the body. 90% of people develop this disease, so for a healthy body, eat a nutritious diet.

    

A person's skin is his “clothing”, which does not wear out over time, because skins constantly die and are born again. In addition, the skin is our organ of touch, that is, it is with its help that we receive information about surrounding objects by feeling them. What is the structure of human skin?

Structure and layers of human skin

If you look at the skin through a device with a fifty-fold magnification, you can see that it is composed of two layers. The top thin layer is called the epidermis. It protects our body from germs and environmental influences and is itself multi-layered.

The lower layers of the epidermis are very sensitive, and new skin cells are constantly created in them. Having been born, such a cell immediately rushes upward and dies almost immediately. It reaches the surface of the skin in the form of scales. Millions of scales form the top layer of the epidermis, which is called the stratum corneum.

The scale cells of the stratum corneum constantly fall off, slough off, and their place is immediately taken by others. The stratum corneum is completely renewed in 7-11 days. When removed from the surface of the skin, the scales take away dirt and germs with them. This structural feature of human skin allows it to serve us throughout our lives “without wearing out.”

The lower layer of human skin is thicker. It contains blood vessels, hair roots, sebaceous and sweat glands. Secretions from the sebaceous glands soften the skin, and secretions from the sweat glands cool it.

In addition, the lower layer of the skin contains various nerve endings, some of which sense pressure, others temperature, others touch, others pain, and so on. The nerves of the skin transmit signals to the human central nervous system, and thanks to this we learn that, for example, we are in pain or cold.

Another important purpose of the lower layer is that it gives the skin strength, forming numerous papillae that penetrate the epidermis. It is their location that determines the pattern of the skin, its folds and grooves.

Why does a person need skin?

There is already one answer to the question of why a person needs skin - it protects the body from mechanical, chemical and many other influences. Let's look at others.

When working, our internal organs produce a large amount of heat, and in order to save our body from overheating, the sweat glands of the skin, if necessary, produce abundant sweat, which, evaporating, carries away excess heat. You can read more about this on the website.

The sweat secreted by the sweat glands of the skin has a salty-bitter taste. This is explained by the fact that salts, lactic acid and nitrogen compounds that are excessive for the human body are dissolved in it, which are removed along with sweat. This is another answer to the question why a person needs skin.

And one last thing. Penetrated with many blood vessels, human skin is a kind of “storage” of blood reserves, which are very necessary during hard work or, for example, when injured. In addition, the skin produces vitamin D, which is necessary for our bone cells to absorb calcium.

As you can see, the structure of human skin is not at all simple, but it completely explains why a person needs skin.

The skin is a very complex human organ and plays an important role in the life of the body. It participates in metabolic processes, regulates body temperature, performs a secretory function and helps internal organs. The skin is a barrier against adverse effects: bacteria, harmful chemical compounds, etc. Structure and functions of the skin Everyone has the same, but appearance depends on many factors. Such as age, race, gender. May vary depending on living conditions and profession, climate.

Skin structure

Skin structure includes sweat glands, hair follicles, sebaceous glands, nails and the skin itself.

Sweat glands perform the function of monitoring body temperature. Most of the sweat glands are located under the arms, in the groin and around the nipples. Sweat production is controlled by the nervous system. The sweat produced is odorless. It is formed as a result of the action of bacteria that appear in an environment favorable to them - wet clothing.
Hair follicle- This is the root of the hair, which is located in the skin and grows. It is supplied with nerve fibers and blood vessels. That's why it hurts us when you pull your hair.
Sebum- a fatty substance consisting of more than 40 types of organic acids and alcohols. It is secreted from the gland into the hair follicle, where it lubricates the hair. Then, coming to the surface of the skin, it forms a greasy, slightly acidic film (the so-called acidic mantle of the skin). The acid mantle of the skin is of great importance for maintaining healthy, intact skin, as it has natural antibacterial properties. Sebum prevents the penetration of harmful substances from the outside and prevents moisture from leaving the body.
Sebaceous glands. They secrete sebum. Sebaceous glands are present in the hair follicle. The level of sebum secretion is controlled by androgens - male sex hormones. When there is an excess of them near the excretory duct of the sebaceous gland, the cells grow and clog the exit. When they come into contact with air, they are chemically attacked (oxidized) and turn black. Consequently, acne formed in this way has nothing to do with clean skin or too high-calorie food. The accumulation of sebum behind the formed obstruction causes a violation of the integrity of the sebaceous gland, and sebum penetrates into the deeper layers of the skin. In this case, it acts as an irritant, and as a result, a pimple appears. When an infection gets into it, the pimple turns into an abscess. If the abscess is squeezed out, an even larger focus of inflammation will form.
Nail is a smooth, slightly convex, translucent horny plate with a hard structure. The main component of the nail is the protein keratin. The nail plate grows throughout life. New tissue forms in the germinal zone (at the base). The nail always recovers.

Skin structure

Skin structure consists of several layers: epidermis, dermis (skin) and hypodermis (subcutaneous fatty tissue).

Epidermis Divided into five layers: basal (deepest), granular, shiny and horny. The basal layer is a set of living cells that divide, grow, develop, age and die, moving up the layer. The life cycle of the epidermis is 26-28 days. The top layer of the epidermis, the horny layer, peels off and is replaced by new cells. The thickest stratum corneum is on the feet and palms. The epidermis performs important functions: antibacterial protection (armor) and maintaining skin moisture levels. The basement membrane does not allow harmful substances to penetrate, and allows moisture to pass through from above.

- This is the top layer of skin, its structure is made up of a network of blood vessels and nerve endings. Contains collagen protein, which evens out skin cells and makes it firm, smooth and elastic. As a result of age-related changes in the skin, collagen fibers and bonds are destroyed, and the skin loses its elasticity, becomes thin and wrinkles appear.

Hypodermis- subcutaneous fatty tissue. The main function of the hypodermis is to provide thermoregulation of the body, that is, to control temperature. Women have a thicker layer of body fat than men. Large concentration of hypodermis in the chest, buttocks and thighs. Therefore, women can better tolerate the hot rays of the sun and icy cold and can stay in the water longer.

Approximately twice a day, skin cells in the basal layer bud. The most intense growth occurs in the morning and afternoon (the time when the level of the hormone cortisol is low). Therefore, this is the best time to take care of your skin. In the morning it is useful to wash your face, massage and use creams.

What determines skin color

The structure and structure of the skin of all people is the same, but color of the skin different. What determines skin color? The skin contains the pigment melanin, which is responsible for coloring. The more it is, the darker it is. Melanin is a granular, dark pigment found in the epidermis, hair, and iris of the eyes. Gives them a specific color and protects them from the harmful effects of ultraviolet rays. It contains special cells - melanocytes in the form of granules located in the basal layer. Regardless of skin color, a person is born with the same number of malanocytes. But the ability of these cells to secrete melanin varies. Warm rays penetrating the skin provoke the release of melanin for protection. Tanning and freckles are the result of melanin.

Functions of human skin

We constantly carry body conditioner on ourselves - this is our skin. 36.6° is a constant body temperature - both in winter and in summer. This is controlled by our brain, it regulates heat transfer to the skin and sweating. The skin secretes sweat, freeing the body from harmful metabolic products and poisons that enter with drink, food, and air. It also helps us breathe, removing 800 g of water vapor per day - twice as much as the lungs. The skin has tactile sensitivity, that is, it perceives the slightest touch to it. Our skin contains a thousand nerve endings in the smallest area. 75 sebaceous glands, 650 sweat glands, 25 meters of nerve fibers, another 65 hair fibers - and all this in 1 square centimeter of skin.

Important functions of the skin

1. Protective (barrier) function. The skin protects the body from harmful microorganisms and chemicals.
2. Exchange function. In the skin, transformations specific to it are carried out: the formation of keratin, collagen, melanin, sebum and sweat. The skin absorbs useful substances and participates in the synthesis of vitamin D. Through the circulatory and lymphatic network of vessels, the metabolism of the skin is combined with the metabolism of the whole body.
3. Storage function. The skin retains toxic substances, protein metabolites (for example, residual nitrogen from a protein diet and some diseases), so it helps to weaken their effect on other organs and the brain.
4. Excretory function. The skin helps to get rid of toxic and excess products of the body (salts, water, drugs, metabolites, etc.).
5. Thermostatic. Helps maintain constant body temperature.
6. Sensitive (tactile). Perceives external influences (pain, heat, cold, etc.), which ensures an adequate response of the body to stimuli. Remember, for example, how quickly we withdraw our hand after accidentally touching a hot iron.
7. Respiratory. The skin participates in the process of gas exchange occurring in the body. Carbon dioxide is released and oxygen is absorbed; this process accounts for only 2% of the total gas exchange of the body.

Beautiful and well-groomed skin can become a real pride, because people are accustomed to evaluating it, first of all, from the point of view of aesthetics. Meanwhile, this is an important organ that performs many functions in our body. Find out what the structure of the skin is and its role in our lives.

Briefly about the properties of leather

Thanks to a complex system of receptors connected to the brain, the skin provides detailed information about the state of the environment and ensures that our body is adapted to external conditions.

The skin consists of three main layers - the epidermis, dermis and subcutaneous tissue.

Epidermis

• basal layer (located deeper than the other layers, also called the germinal layer due to the fact that mitotic division and proliferation of keratinocytes take place in it);


• stratum spinosum - several rows of polygonal cells, between which there is a space filled with desmoglein;


• granular layer - consists of cells whose nuclei are filled with keratohyalin granules, an important intermediate product in the production of keratin;


• shiny layer - located in places where the skin is susceptible to active mechanical influences (on the heels, palms, etc.), serves to protect the deep layers;


• stratum corneum - contains the protein keratin, which has the ability to bind water, due to which our skin acquires elasticity.

The epidermis also contains cells whose function is to prepare the pigment melanin. It is what gives skin and hair color. When exposed to increased amounts of ultraviolet light, melanin production increases (giving the tanning effect). Excessive and too intense sun exposure, however, can damage the deeper layers of the skin.

Dermis

1. Papillary layer - This includes the dermal papillae, which contain a number of small blood vessels (papillary tissue). The dermal papillae also contain nerve fibers, sweat glands and hair follicles.


2. The reticular layer lies above the subcutaneous tissue and has a large amount of collagen fibers and connective tissue. There are deep vascular plexuses between the dermis and subcutaneous tissue, but the reticular layer practically does not contain capillaries.

Collagen fibers are created by the protein collagen (it belongs to the group of scleroproteins) and are an important component - thanks to collagen fibers, our skin is elastic. Unfortunately, as we age, the production of collagen fibers decreases, causing the skin to sag (wrinkles appear)

Elastic fibers - got their name due to their ability to reversibly stretch. They protect collagen fibers from excessive stress.

Smooth muscle fibers lie near the subcutaneous tissue and are created by an amorphous mass of mucopolysaccharides, which contain hyaluronic acid and protein complexes. Thanks to smooth muscle fibers, our skin takes important nutrients from the subcutaneous layer and transfers them to different layers.

Subcutaneous tissue

Skin appendages

• hair;


• nails;


• sweat glands;


• mammary gland;


• sebaceous glands.

Nails are horny plates that perform a protective function for the fingers.

Sweat glands are tubular in shape and located in the dermis and subcutaneous tissue. There are 2 types of sweat glands:

• eccrine glands - present on the entire surface of the skin and participate in thermoregulation by secreting sweat;


• apocrine glands - present in the genital area, anus, nipples and armpits, their activity begins after puberty

Mammary glands are developed in women and are necessary for milk production.

Skin functions

Passive functions:

• protection from cold, heat, radiation;


• protection from pressure, impact, friction;


• protection against chemicals (skin has a slightly acidic pH);


• protection against germs, bacteria, viruses, fungi (due to the fact that the top layer is constantly peeled off and renewed).

• fight against pathogenic microbes in the skin (phagocytes, immune system);


• thermoregulation (sweat production, the nervous and vascular system of the skin are controlled by signals from

Among all the organs of the human body, the skin is the largest. We present to your attention 10 interesting facts about our skin.

Square

People have different heights, fullness, and, accordingly, the skin area will differ from person to person, but on average this figure is at the level of 1.5-2.5 m2. The weight of multi-layered skin is over 11-15 percent of a person’s weight.

Does the skin area of ​​an adult reach 1.5-2.5 m2?

Thickness

A baby's skin thickness is one millimeter. As you get older, it remains thin only on the eyelids. In an adult, the average skin thickness increases several times. The palms of the hands and soles of the feet are the places with the thickest skin.

The palms of the hands and soles of the feet are the places with the thickest skin.

Update

This separate organ has its own specific functions; there are from 300 to 350 million skin cells in the body. The body must produce more than 2 billion skin cells per year. The fact is that in a year all skin cells are replaced at least 6 times (a complete replacement takes 55-80 days). The process of completing the cell cycle occurs at a rate of 0.6 million horny scales/hour (this amount corresponds to a weight of 0.7-0.8 kg).

Human skin at high magnification. Horny scales are clearly visible.

Complex structure

The skin has a complex structure; it contains cells of different types. In addition, the largest human organ contains glands (sebaceous and sweat), capillaries and hair. In a square centimeter of skin there are about 230-250 glands (200 sweat, 30-50 sebaceous), two meters of capillaries and two dozen hairs.

Sweating ability

A person sweats and this is very good for his body. Sweat released on the surface of the skin helps cool it. The work of the kidneys is facilitated; due to the work of the sweat glands, the body gets rid of excess moisture and harmful products that arise during the digestion of food during metabolism. In hot weather, several liters of sweat (3 or more) can be released through the pores of the skin surface.

In hot weather, several liters of sweat can be released through the pores of the skin surface.

Vitamin D synthesis

When certain conditions are created, the skin can serve as a synthesizer of useful substances. For example, when sunlight hits the skin, complex processes occur that contribute to the synthesis of vitamin D. From this point of view, tanning is useful, but we should not forget about the destructive properties of ultraviolet rays for all living cells. In a solarium and in the sun, tanning your skin should be done in moderation and in a certain regimen recommended by doctors.

When sunlight hits the skin, complex processes occur that promote the synthesis of vitamin D

Multifunctionality

Among the main functions assigned to the skin by nature are the following:

• protective function from overheating of the body and mechanical damage, from radiation, including the ultraviolet part of the light spectrum, from microbes and harmful substances;
• function of regulation through the sweating mechanism of equilibrium in the amount of water, the presence of certain substances;
• through the skin, the body and the external environment exchange necessary substances; the skin, to some extent, is an auxiliary respiratory organ;
• tactile function: receptors are built into the skin, due to them a person has a sense of touch;
• appearance shaper function: features of facial skin and subcutaneous facial muscles allow you to visually distinguish one person from another and convey your emotions.

The facial properties of the skin allow us to convey our emotions to each other.

Waterproof

The waterproofness of the skin is ensured by its outer layer, the epidermis. Its cells are in very close contact with each other and have a layer of fat on the outer surface. If the body is in water for a long time, the extracellular layer of fat becomes thinner and the water gains access to the skin cells, as a result it swells.

Wrinkled skin from prolonged exposure to water

Cleanliness and excessive sterility

On the surface of the skin there are colonies of beneficial microorganisms that help in the fight against pathogenic bacteria. If you achieve absolute sterility, you can weaken the protection: excessive sterility is harmful to the skin.

Bacteria on the skin under a microscope

Dead cells and dust

Over the course of his life, each person loses up to hundreds of kilograms of horny scales, which turn into dust. In the air of your home (office) or apartment, when a ray of sunlight penetrates, you can clearly see a huge amount of tiny dust. Almost 2/3 of this dust consists of skin horny scales. Billions of tons of dust particles of the same composition are absorbed by the planet's atmosphere.

Almost 2/3 of the dust in your room consists of skin horny scales.

Sincerely,