The skin seems to be the most complex and most voluminous organ of a person. In our life, it plays a crucial 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 is. And, of course, this is not the only value of the skin for the body. She still has many functions that should be examined in detail. This will require a basic review of the structure of the skin and its cellular composition, functioning mechanisms.
Basic skin function overview
Among the many functions of the body, many can be realized only in the presence of skin. If we consider it from a phylogenetic point of view, the obvious conclusion is that it was created to save fluid in the body. It was necessary for the organisms to populate the land. Moreover, in phylogenesis, the skin appeared much later than scales and shell, significantly surpassing them in flexibility of adaptation to environmental conditions, but still performing basic functions. Among them:
regulation of body temperature;
protective (barrier);
regulatory (participation in water-electrolyte metabolism);
funded (serves as a place for blood deposition);
metabolic and endocrine;
receptor;
immune
excretory.
The above functions are very important because they support the functioning of organ systems. And this is the significance of the skin for the body: it is responsible for interacting with the environment, but at the same time it protects it from its destructive effects. It removes fluid from the body, but at the same time "monitors" its temperature so that it is not removed more than it should. 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.
Structural features of the skin
In the educational complex “We and the world around us” in the section “Importance of the skin for the body” (Grade 4) contains information about its structure. The materials for this training manual 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 about their functions.
The skin morphology is represented by three layers: the epidermis (upper layer), dermis (reticular and papillary layer) and adipose tissue. The latter is located most deeply. These three layers form our cover. Adipose tissue develops in the subcutaneous tissue, performing a metabolic function.
In the dermis there are germinal zones of the skin, blood vessels, as well as nerve endings (receptors). The latter are able to recognize the physical characteristics of the medium with which they are in contact. Also in the dermis are the end sections of sweat glands and hair, equipped with a fat bag.
The epidermis is the least active part, because it performs only a protective function. However, the value of the skin for the body is great and thanks to it, because without protection the human body would be instantly subjected to various influences, including physical, biological and chemical factors. Even a simple temperature, or rather its fluctuation within 10 degrees, could destroy us, if not for the presence of a multilayer epidermis.
The role of 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 process of regulating body temperature occurs . In a situation where environmental indicators exceed bodily, the body includes processes of sweating and expansion of the loop vessels of the skin. Due to this, it cools, and existence in such conditions becomes more comfortable.
In a situation where the temperature outside the body is lower, the skin determines this by activating the cold receptors. They are about 5-6 times more than thermal receptors. Then the process of reducing heat transfer by narrowing the blood vessels and reducing the skin surface (goose bumps) starts . In addition, the processes of lipid cleavage in the fiber are enhanced, which allows you to produce some of the heat to warm and maintain the body's life support.
Protective function
However, thermoregulation is far from the only value of the skin for the human body. Equally 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 transdermal intake of substances that can dissolve in water.
Also, the layer of epidermal cells protects against mechanical factors - squeezing, puncturing, cutting. The epidermis is much harder than the dermis and fiber, and therefore any of these effects would cause serious damage if it were not for this layer on the surface.
No less important is the protection against ionizing radiation, at least from long-wave radiation with medium and low frequencies. In particular, the skin protects well from ultraviolet radiation, although it cannot protect the body from gamma rays of x-rays. Not surprising, because the latter are able to penetrate through concrete walls. But even the presence of protection against neutron radiation, from alpha particles and from ultraviolet radiation significantly prolongs a person’s life.
And since not only physical factors are capable of killing 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 and colonize its thickness through the skin. 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 value of the skin for the human body briefly characterizes all the processes of its adaptation to environmental factors.
Water-electrolyte regulation
The great importance of the skin for the body lies in the regulation of water-electrolyte balance. What is achieved by the release of sodium, water and chlorine ions along with sweat. Also, some toxic substances of an acidic nature are 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, through the sweat gland, water is released outside. 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, skin temperature decreases slightly. By the way, this biological process is not effective for cooling the body in situations when the environment is hot (for example, in a bath).
Blood deposition function
In the dermis is one of the widest and most complex vascular networks. Moreover, there are only three of them: two arterial and one venous. Moreover, wide capillaries are present in the skin, in which blood may be retained. This allows you to accumulate some of it in order to release and return to the bloodstream for gas exchange during a physiological reaction of stress.
In total, up to 15% of the total blood volume, which is constantly changing to prevent sludge and thrombosis, can simultaneously accumulate in the vessels of the skin. As soon as a 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 will return from the capillaries to the systemic circulation. The body as a result of this will increase stamina and strength. And since this often saves lives in case of danger, the importance of the skin for the human body in this regard is simply enormous.
Endocrine and metabolic functions
Subcutaneous tissue is an organ that stores fat. The latter is spent sparingly to provide backup energy needs. It is from fiber that fat is absorbed by the body in the last place, so losing weight is so difficult. However, now this value of skin for a person is not the main thing. Endocrine function, namely the regulation of hunger and satiety, is much more important.
Adipose tissue of the subcutaneous tissue is a powerful gland that can secrete substances that regulate saturation. And about the feeling of hunger "reports" the level of glucose in the blood. As soon as he falls, hunger appears. As it is saturated, it is inhibited by hormones from adipose tissue, which "say" that you should not eat more.
Skin receptor function
Discussing the topic "The importance of skin for the body" (the 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 get information about the environment. The skin through receptors determines the temperature of the medium, 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 "guard dog" of human health.
Excretory function of the skin
The 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 acid reaction. The former are the proteins and fats needed for hair treatment, into the bulb of which the duct of the sebaceous gland opens.
The 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 is later excreted through the skin in the form of crystals.
Another example, unfortunately, is imperfect. It is associated with an attempt to eliminate bile acids in parenchymal lesions of the liver. However, all the same, this value of the skin for the vital activity of the body is extremely large, 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
You must admit that skin is of great importance to the human body. Pictures on the subject, attached as a visual material, demonstrate what a complex structure our outer cover has. It’s hard to imagine, but there are also immune reactions that are important for protecting the entire body. Moreover, protection is not from external enemies and factors, but from pathogens that have fallen into the internal environment. And this function is realized through neutrophils, monocytes, macrophages and lymphocytes.
Also in the skin are Langerhans cells and basophils. They regulate local protective immune responses and participate in the presentation of antigens to plasmocytes. 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 place of synthesis of provitamin D., important for the development of the human immunity and skeleton.
In the future, it will go through the processing stage in the kidneys and will fulfill its function. However, the place of its formation is skin. Here, under the influence of ultraviolet light, a small amount of which the skin nevertheless carefully passes through itself, this substance arises. And its importance for the development of the skeleton is enormous. And the role of the skin for the whole organism is even greater.