The skin covers the human body from the outside, it provides protection for all internal organs from external influences (friction, pressure, shock, rupture). In addition, the cover prevents the penetration of various bacteria into the body. Its thickness in various areas ranges from 0.5 to 4 millimeters, an approximate mass of 3 kg.
The structure of the skin allows it to participate in metabolic, excretory and protective processes, as well as thermoregulation of the body (temperature regulation). About 500 milliliters of water are released through the cover throughout the day. This makes up 1% of the total body volume. The structure of the skin involves the removal of protein metabolism products and various salts. The cover absorbs oxygen, releasing carbon dioxide. Mineral, water and gas metabolism of the cover in intensity is only slightly inferior to the intensity of metabolism in the muscles and liver.
The structure of human skin allows you to perform a signaling function - it is provided in large numbers by sensitive receptors located in all its layers. With their help, people are able to perceive pain, pressure, warmth, touch. The structure of the skin allows you to settle in separate areas in 1 square. see up to twelve cold, two hundred painful, two thermal and twenty-five pressure-responsive endings. It should be noted that the presence of sensitivity performs the most important task of the interaction of the body and the environment, prevents burns, injuries, frostbite.
Leather. Structure.
The normal functioning of the body is ensured by the presence of constant conditions of existence. External factors are quite variable and have a constant effect on a person. Ensuring and maintaining the integrity of the whole organism lies on the outer cover of the body. The structure of the skin is quite complicated. This organ is represented by three layers.
The topmost is the epidermis. It has a thickness of 0.03 to 1.5 millimeters or more (for example, on the sole or palms). It, in turn, consists of five layers. The surface layer (horny) is represented by dead keratinized cells that are tightly adjacent to each other. They are constantly being separated and replaced with new cells. The epidermis has a protective function. It is he who prevents the influence of external factors on the body. Due to its structure, the epidermis has elasticity, strength and elasticity. In addition, he is able to recover quite quickly with minor damage. Each of its five layers ripens into one another, thus, there is a constant update. Fully cells are updated for 26-28 days. Of all their organs, only skin cells are able to multiply and grow at such a rate.
The next layer of the outer half-blood - the dermis - is represented by interwoven fibers. The main ones are collagen and elastin (collagen and elastin are the main structural skin proteins). Due to them, the cover has elasticity, is able to restore its original state after stretching. In the dermis, two layers are distinguished. Lymphatic and blood vessels, muscles, nerve endings, sebaceous and sweat glands, hair pass through a deep layer.
Subcutaneous fatty tissue (hypodermis) is located under the dermis. This layer is a kind of "pillow". Its thickness is different, depending on the area of the body. This determines the roundness of body shapes. Hypodermis protects the body from hypothermia, trauma, and external stimuli; it is an accumulative layer where fat reserves used up during illness, pregnancy, and hunger are deposited.
In almost every area of the skin, sweat glands are located . Most of them are on the pads of the fingers and toes, soles, palms, in the inguinal and axillary folds. These glands are involved in excretory function.
Sebum is a secret secreted by the sebaceous glands. It makes the skin supple, softens it.