skin is the most complicated and most voluminous body of a man.Our ability to live it plays an important role, and therefore is the main structural element of the body.Protecting, preserving heat and water balance, it supports life in the conditions in which the person resides.And, of course, is not the only significance of the skin to the body.It has many functions, which should be thoroughly understand.This will require a review of the basic structure of the skin and its cellular composition, functioning mechanisms.
basic overview of the functions of the skin
Among the many, many functions of the body can be realized only if the skin.If we look at it from a phylogenetic point of view, the conclusion is obvious that it was created to conserve the fluid in the body.It was necessary that the organisms colonized the land.And in the phylogeny of the skin it appeared much later scales and armor, greatly exceeds them the flexibility to adapt to the environment, but still performing basic functions.Among them:
regulation of body temperature;
Regulating (participation in the water and electrolyte exchange);
funded (the deposit serves as a place of blood);
metabolic and endocrine;
The above features are very important, because it supports the functioning of the organ systems.And this is the value of the skin to the body: it is responsible for interaction with the environment, but at the same time protects it from harmful effects.It takes fluid from the body, but also "monitors" for its temperature, so as not to be removed more than they should.In some organisms, the skin is also involved in the exchange of gases, playing the role of additional light.In humans, this function - due to the complex structure of its respiratory organs - loss.
Structural features leather
The educational complex "We and the world" in the "value of the skin to the body" (Grade 4) provides information about its structure.Materials for this tutorial were taken from books on the histology and physiology of the skin.They provide more detailed information on the structure of the outer covering of the body of the cells involved in its formation, and how they function.
morphology of the skin consists of three layers: the epidermis (the top layer), dermis (papillary and reticular layer) and fatty tissue.The latter is most deeply.These three layers and shape our cover.The subcutaneous tissue develops adipose tissue, metabolic function performs.
are located in the dermis growing zone skin, blood vessels and nerve endings (receptors).The latter can recognize the physical characteristics of the medium which are contacted.Also in the dermis are arranged end portions of the sweat glands and hair fat equipped bag.
epidermis - it is the least active part, because it only performs protective function.However, the value of the skin to the body large and thanks to him, because without the protection of the human body immediately subjected to various influences, including physical, biological and chemical factors.Even a simple fever, or rather its oscillation in the range of 10 degrees, could destroy us if it were not for the presence of a multi-layer of the epidermis.
role of skin thermoregulation
principal value of the skin in the process of thermoregulation difficult challenge.It is this body has thermoreceptors through which can determine the approximate ambient temperature.Based on this information, the process of controlling the temperature of the body.In a situation where performance exceeds the physical environment, the body includes the processes of sweating and skin blood vessels expand the loop.Due to this, it cools, and the existence of such conditions becomes more comfortable.
In a situation where the temperature is lower than the body, the skin defines this cycling of cold receptors.There are about 5-6 times greater than the heat receptors.Then reduce the heat transfer process is started by narrowing vessels and reducing the surface of the skin (goose bumps).In addition, enhanced lipid digestion processes in the tissue, which allows the production of some of the heat to warm the body and maintain life support.
thermoregulation, however - this is not the only value of the skin to the human body.Equally important is protection not only against heat and cold, but also on other factors of 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 flow of substances that can be dissolved in water.
layer of epidermal cells also protects against mechanical factors - crushing, puncturing, cutting.The epidermis is much harder than the dermis and fat, and therefore any of the actions would lead to serious damage, not whether that layer on the surface.
Equally important is the protection from ionizing radiation, at least on medium and long-wave with low frequency.In particular, the skin good protection from ultraviolet radiation, although it may protect the body from the gamma-ray photons.Not surprisingly, since the latter are able to penetrate through the concrete walls.But even the presence of protection against neutron radiation from alpha particles and ultraviolet radiation from the significantly extends the life of man.
And because not only physical factors can kill our bodies, it must develop a defense against biological aggressors.They are saprophytic bacteria, viruses, fungi and protists.Of all of them can be absorbed through the skin and populate its thickness only fungi.And because of their mycelia branch and gets into the gaps between epidermal scales, stopping them.But bacteria and viruses from the epidermis firmly defends the body, and the value of the skin to the human body briefly describes all the processes of adaptation to environmental factors.
water and electrolyte regulation
very important for the body is the skin and in the regulation of water and electrolyte balance.What is achieved by excretion of sodium, water and chloride ions in sweat.Also, with this liquid is removed and some toxic substances of an acidic nature.This creates interesting possibilities for the body, which is cooled by its own liquid.
The physical nature of the evaporation process is as follows: first, through the sweat gland water is excreted.Sweat from the skin surface to evaporate, thereby cooling it.In this evaporation causes a loss of kinetic energy of water molecules.As a result, skin temperature is slightly reduced.By the way, the biological process is not effective for cooling the body in situations when hot environment (e.g. in the bath).
function escrow blood
The dermis is one of the most extensive and complex vascular networks.At the same time there are only three: two arterial and venous one.Moreover, in the present wide skin capillaries in which the blood can be trapped.This allows you to store some of it to a physiological stress response in the release and return to the bloodstream for gas exchange.
Total vascular skin can simultaneously accumulate up to 15% of the total blood volume, which is constantly changing in order to prevent sludge and thrombus formation.Once it arrives humoral signal that you want to extend the arterioles of the body and set it in motion because of the above-threshold stress, the blood from the capillaries back into the systemic circulation.The organism as a result of this added to the endurance and power.And because it often saves lives in the event of danger, the value of the skin to the human body in this regard simply enormous.
endocrine and metabolic functions
Subcutaneous tissue - body fat accumulation.Last consumed sparingly for backup power needs.It is because fat tissue is taken by the body at the last turn, so to lose weight so difficult.Now, however, the value of the skin to the person - not the main thing.Much more important endocrine function, namely the regulation of hunger and satiety.
subcutaneous tissue Adipose tissue is a powerful gland that can release substances that regulate satiety.And the feeling of hunger, "said" the level of glucose in the blood.Once it falls, there is hunger.As the saturation it inhibits hormones from adipose tissue, which "speak" about what to eat more food should not be.
skin Discussing the topic "The value of the skin to the body" (4th grade school studies it), it is impossible to ignore the receptor function.It - one of the most important, because it provides information on the environment.The skin through receptors determines the temperature of the medium, the density of some items, humidity, surface texture, and other morphological parameters.
Even pain receptors located in the skin that protects us from receiving large damage.And that pain is the "watchdog" of human health.
excretory function of the skin
skin due to the presence of sweat glands is able to excrete metabolic products.Typically, this high molecular weight lipophilic substances or hydrophilic small molecule with an acidic reaction.The first are proteins and fats, it is necessary for the treatment of hair in the follicle which opens a sebaceous gland duct.
second substance (low molecular weight) come here directly from the blood and come to the surface with sweat.It is remarkable that the excretory function of the skin is clearly a disease, such as gout.In its development into the blood significantly increased the amount of uric acid, which is output later through the skin in the form of crystals.
Another example, unfortunately, imperfect.It is associated with an attempt to excretion of bile acids in the liver parenchymal lesions.But anyway, this value for the life of the body's skin is extremely great because it helps regulate the exchange of toxic and hazardous substances.And this is one of the mechanisms of human life support.
Agree great value to the skin of the human body.Pictures on the topic, is attached as visual aids, show what a complicated structure is our outer covering.It is difficult to imagine, but there also occur immune responses that are important for the protection of the entire body.And do not protect against external enemies and factors, from pathogens got into the internal environment.And this function is implemented by means of neutrophils, monocytes, macrophages and lymphocytes.
also present in the skin Langerhans cells and basophils.They regulate the local protective immune response, and are involved in antigen presentation plasma cells.It is noteworthy that the immune function of the skin is mediated and another important mechanism that should be regarded as metabolic.Our outer covering is a place of synthesis is important for the development of the immune system and the human skeleton provitamin D.
In the future it will be the step of treating kidney and will perform its function.However, the place of its formation is the skin.Here, under the influence of ultraviolet light, which is a small amount of skin is still carefully passes through itself, is born this substance.And its importance for the development of the skeleton is enormous.And the role of the skin to the entire body even more great.