Skin seems to be the most complex and most voluminous human organ. In our life, it plays an important role, and therefore is the main structural element of the body. Providing protection, maintaining heat and water balance, it supports life in the conditions in which a person lives. And, of course, this is not the only value of the skin for the body. It has many more features that need to be explored in detail. This will require a basic consideration of the structure of the skin and its cellular composition, mechanisms of functioning.
Basic overview of skin functions
Among the many functions of the body, many can only be realized with the presence of skin. When viewed from a phylogenetic point of view, the obvious conclusion is that it was created to conserve fluid in the body. This was necessary for organisms to populate the land. Moreover, in phylogenesis, the skinappeared much later than the scales and shell, significantly surpassing them in the flexibility of adapting to environmental conditions, but still performing the main functions. Among them:
- regulation of body temperature;
- protective (barrier);
- regulatory (participation in water-electrolyte metabolism);
- accumulative (serves as a place for depositing blood);
- metabolic and endocrine;
- receptor;
- immune;
- excretory.
The above functions are very important, because they support the functioning of organ systems. And such is the significance of the skin for the body: it is responsible for interacting with the environment, but at the same time protects from its destructive effects. It removes fluid from the body, but at the same time "monitors" its temperature so that more than it should be removed. In some organisms, the skin also participates in the exchange of gases, playing the role of additional lungs. In humans, this function - due to the complex structure of its respiratory organs - has been lost.
Skin structural features
In the educational-methodical complex "We and the world around us" in the section "The value of the skin for the body" (Grade 4) contains information about its structure. Materials for this study guide were taken from books on histology and physiology of the skin. They provide more detailed information about the structure of the outer cover of the body, about the cells,involved in its formation and their functions.
Skin morphology is represented by three layers: epidermis (upper layer), dermis (net and papillary layer) and adipose tissue. The latter is the deepest. These three layers form our cover. Adipose tissue develops in the subcutaneous tissue, which performs a metabolic function.
In the dermis are the growth zones of the skin, blood vessels, and nerve endings (receptors). The latter are able to recognize the physical characteristics of the environment with which they are in contact. Also in the dermis are the end sections of the sweat glands and hair, equipped with a fat bag.
The epidermis is the least active part, because it only performs a protective function. However, the significance of the skin for the body is great and thanks to it, because without protection, the human body would instantly be exposed to various influences, including physical, biological and chemical factors. Even a simple temperature, or rather its fluctuation within 10 degrees, could destroy us if it were not for the presence of a multi-layered epidermis.
The role of the skin in thermoregulation
The main importance of the skin in the processes of thermoregulation is difficult to dispute. It is this organ that has thermoreceptors, through which it can determine the approximate ambient temperature. Based on this information, the body temperature is regulated. In a situation where environmental indicators exceed those of the body, the body turns on the processes of sweating and expansion of the loop vessels of the skin. DueThis cools him down, and existence in such conditions becomes more comfortable.
In a situation where the temperature outside the body is lower, the skin detects this by activating cold receptors. There are about 5-6 times more of them than thermal receptors. Then the process of reducing heat transfer starts by constricting blood vessels and reducing the skin surface (goosebumps). In addition, the processes of lipid cleavage in fiber are enhanced, which allows the production of some of the heat to warm and maintain the life support of the body.
Protection function
However, thermoregulation is far from the only value of the skin for the human body. No less important is protection not only from heat and cold, but also from other factors of a chemical, biological and physical nature. The main role in the implementation of the barrier (protective) function belongs to the epidermis. Its lipophilic structure limits the percutaneous supply of water-soluble substances.
Also, the layer of epidermal cells protects against mechanical factors - squeezing, piercing, cutting. The epidermis is much harder than the dermis and fiber, and therefore any of these effects would lead to serious damage without this layer on the surface.
No less important is protection from ionizing radiation, at least from long-wave with medium and low frequency. In particular, the skin protects well from ultraviolet radiation, although it cannot protect the body from gamma rays.x-ray quanta. Not surprising, because the latter are able to penetrate through concrete walls. But even the presence of protection from neutron radiation, from alpha particles and from ultraviolet radiation significantly prolongs a person's life.
And since not only physical factors can kill our body, it must develop protection against biological aggressors. They are saprophytic bacteria, viruses, fungi and protists. Of all of them, only fungi can penetrate the skin and populate its thickness. And only because their mycelium branches and falls into the gaps between the epidermal scales, lingering in them. But the epidermis reliably protects the body from bacteria and viruses, and this significance of the skin for the human body briefly characterizes all the processes of its adaptation to environmental factors.
Water and electrolyte regulation
The great importance of the skin for the body lies in the regulation of water and electrolyte balance. What is achieved by the release of sodium, water and chloride ions along with sweat. Also, some toxic substances of an acidic nature are also removed with this liquid. This creates interesting opportunities for the body, which is cooled by its own fluid.
The physical essence of the evaporation process is as follows: first, water is released through the sweat gland. Sweat evaporates from the surface of the skin, thereby cooling it. In this case, evaporation leads to a loss of kinetic energy of water molecules. As a result, the skin temperature drops slightly. By the way, this biological process is not effective for cooling the body in situations wherethe environment is hot (e.g. in a sauna).
Blood deposit function
The dermis contains one of the widest and most complex vascular networks. Moreover, there are only three of them: two arterial and one venous. Moreover, there are wide capillaries in the skin, in which blood can linger. This allows you to accumulate a certain amount of it in order to release it and return it to the bloodstream for gas exchange during a physiological stress reaction.
In total, up to 15% of the total blood volume can simultaneously accumulate in the skin vessels, which is constantly changing to prevent sludge and thrombosis. As soon as the humoral signal is received that it is necessary to expand the arterioles of the body and set it in motion due to suprathreshold stress, blood from the capillaries will return to the systemic circulation. The body as a result of this will add in endurance and strength. And since it often saves lives in case of danger, the value of the skin for the human body in this regard is simply enormous.
Endocrine and metabolic functions
Subcutaneous tissue is an organ of fat storage. The latter is used sparingly to provide backup energy needs. It is from fiber that fat is taken by the body at the very last turn, which is why it is so difficult to lose weight. However, now this value of skin for a person is not the main thing. Much more important is the endocrine function, namely the regulation of hunger and satiety.
Subcutaneous adipose tissue is a powerful gland capable ofrelease substances that regulate satiety. And about the feeling of hunger "reports" the level of glucose in the blood. As soon as it falls, hunger appears. As it fills up, it is inhibited by hormones from adipose tissue, which "tell" that you should not eat more food.
Receptor function of the skin
When discussing the topic "The importance of the skin for the body" (4th grade of the school studies it), it is impossible to ignore the receptor function. It is one of the most important, because it allows you to obtain information about the habitat. The skin through receptors determines the temperature of the environment, the density of some objects, humidity, surface texture and other morphological parameters.
Even pain receptors are located in the skin, which protects us from major damage. And it is pain that is the "watchdog" of human he alth.
Excretory function of the skin
Skin due to the presence of sweat glands is able to excrete metabolic products. As a rule, these are high molecular weight lipophilic substances or hydrophilic small molecules with an acidic reaction. The former are proteins and fats needed for hair treatment, into the bulb of which the duct of the sebaceous gland opens.
Second substances (low molecular weight) get here directly from the blood and come to the surface with sweat. It is noteworthy that the excretory function of the skin is clearly represented by a disease such as gout. With its development in the blood, the amount of uric acid increases significantly, which laterexcreted through the skin in the form of crystals.
Another example, unfortunately imperfect. It is associated with an attempt to excrete bile acids in parenchymal liver lesions. However, all the same, this value of the skin for the life of the body is extremely high, because it helps to regulate the exchange of toxic and harmful substances. And this is one of the mechanisms of human life support.
Immune function
Agree, the importance of the skin for the human body is great. Pictures on the topic, attached as visual material, demonstrate what a complex structure our outer cover has. It’s hard to imagine, but immune reactions also take place here, which are important for protecting the entire body. Moreover, protection is not from external enemies and factors, but from pathogens that have entered the internal environment. And this function is realized through neutrophils, monocytes, macrophages and lymphocytes.
Also, Langerhans cells and basophils are present in the skin. They regulate local immune responses and are involved in the presentation of antigens to plasma cells. It is noteworthy that the immune function of the skin is also mediated by another important mechanism, which should be considered metabolic. Our outer cover is a site for the synthesis of provitamin D, which is important for the development of immunity and the human skeleton.
In the future, it will pass the stage of processing in the kidneys and will perform its function. However, the place of its formation is the skin. Here, under the influence of ultraviolet light, a small amount of which the skin is stillcarefully passes through itself, this substance is born. And its importance for the development of the skeleton is enormous. And the role of the skin for the whole organism is even greater.
