The range of functions of the skin

The skin is involved in renal excretory function, covers the entire surface of our body and plays a very important role in the life of the organism. We usually have little to think about its meaning and know little about what the functions, duties skin is extremely diverse. With six of the most important of them we will learn in the conversation.
The skin consists of several tens of layers of cells, and the lower layers are living, active, proliferating cells, and the top - cells dead. However, these dead cells filled with a substance that is part of the hair, nails, horns, and therefore called Horny, play a vital role in protecting the body from harmful influences. Here we see a unique phenomenon not seen in any other system bodies: dead cells perform a specific function in the body. His death they provide life other systems and organs. No matter how soft the skin to the touch, covering several layers of dead skin cells make the skin firm. How can you compare it with the mucous membranes separate parts of the nasal cavity (which so easily bleeds), not to mention the tissues covering the inside of the bronchi, the intestines, the pleura!
Under the surface, epithelial tissue, which we have just described, is the layer of connective tissue, fiber and fat, which scattered the sweat and sebaceous glands, branching dense network of blood vessels are the numerous branches of the nerves of different receptors. Finally, we should mention Horny skin appendages, such as hair and nails. All this rich Arsenal allows the skin to perform their multiple responsibilities. As already mentioned, the main functions of the skin six.
The excretory function of the skin, which we have already said, is not the most important of its duties. We call it first just because it gave us an opportunity to speak about the skin in this conversation. However, if the principal place in importance among the excretory organs occupy kidneys, skin should take second place. It is in this respect important intestines. Chronic kidney disease is possible to a certain extent, compensate for the lack of the work of these bodies by increasing the sweat glands. Not accidentally resorts for renal patients are arranged in the most heated areas (Bairam-Ali in Turkmenistan, Cairo in Egypt, and so on).
If to consider, that during the day, the sweat glands in normal conditions allocate not less than 10 grams of solid waste metabolism (salts, urea, and so on), it becomes clear how important the health of the skin. If we fail to keep your skin clean, won't remove accumulated harmful substances and dead cells flaking, we risk to cause disease of the skin and to disrupt its work.
Analytic function of the skin is very important. Indeed, the skin is one of the main organs of sense. When enumerating the five senses of man, name and touch. We will see later that the person has not five, but much more kinds of sensitivity. In particular, it is extremely diverse types of skin sensitivity. First, it is the sense of touch, or feel; second, a sense of heat; third, feeling cold; fourth, the feeling of pain. Of all the senses the skin is the largest, and the huge surface of the senses densely distributed special built receptors, perceiving different types of stimuli. From these receptors are running signals to the brain, and in response there are various reflex reactions; OTDELENIE hands with pain, pallor of the skin (i.e. narrow its vessels) when cooled, etc.
The function of the skin as depot blood we have already mentioned. A rich network of skin capillaries can accommodate about 1/10 of all the blood of the body, i.e. about 0.5 liters. It should be borne in mind, blood in the depot, as in the lungs and liver, not kept still. She just moves several times slower than actively circulating blood. We said that only in the spleen blood really is in the full sense of it in reserve until the right moment does not participate in the General movement.
Thermoregulatory function is one of the main duties of the skin. An important feature of the higher animals and man is a constant body temperature. The frog and other lower vertebrates, not to mention insects and other animals that stand even lower on the evolutionary scale, body temperature depends on the ambient temperature. If the external temperature is 40 C, such will be the same body temperature frogs. When it is getting cold and the temperature of water and air is reduced to 2-3 C, and reduced body temperature of the animal. If it freezes, the metabolism processes become extremely sluggish; the animal falls into winter hibernation. In humans and higher animals, regardless of the surrounding conditions, remains the same temperature of the body. In the armpit on the average of 36.6 °N In different parts of the skin temperature is different. So, on her belly she is 34 C, and in the face of 20 to 25 degrees C. Subject that seems warm on your face, will give stomach feeling cold. The difference is clear: the person is always open, and his body covered clothes. The temperature of the blood and internal organs higher than in the armpit, and is 37,5-38,5 °S. Temperature of our internal environment is strictly constant. The life of the body is possible only within 32-43 °N
How the body maintains a constant temperature when the temperature changes of the external environment? The first mechanism here is the change of heat skin, the second a change of production, heat production in the body.
If the air temperature drops, cold receptors send appropriate signals to the brain. In addition, flowing to the skin blood stronger cooled and then bathe the brain, it also annoys. In response from the brain go impulses constricting the blood vessels of the skin. Skin pale. Now it was flowing less blood - heat by the body decreases. If, however, the cooling greatly, and included a second mechanism. With it is familiar to each of us. For example, you're standing at the bus stop waiting for a bus. Wind gusts pervade you. From the cold you start to shiver, mentally cursing stuck somewhere bus and its folly on the part of the service. Have you considered the idea that the body with cold shake provides you with the service? Jitter is a useful response. There is a reduction of muscles. Is increases in heat. Wanting to get rid of unpleasant cold shiver, you begin to actively move than engaging extensive muscle groups. Why muscles generate heat, we already know from previous conversations. Know that in the heat turns 80 % of that energy which is released during chemical processes in the working muscles. Increases metabolism and in other tissues, especially the liver. Not accidentally prolonged exposure to the cold increases urination: increased metabolism speeds up the formation of slag.
Children are less likely than adults to fight the cold. If the child is below the father in 2 times, the surface of the body (as it happens heat) it has less than 3-4 times, the weight of the body heat-generating less 6-8 times. Thus for a given surface heat accounts for less than half the mass of tissue. Each cell have to double the production of heat.
If it gets hot, irritated not cold, and heat the skin receptors. In response increases output by expanding the blood vessels of the skin - it is now more blood was flowing. With the further increase of temperature begins reinforced sweat glands. The value of the pot here is to evaporate from the skin or clothing. One gram of sweat evaporation takes 580 small-calories of heat. If the pot will just run off and removed from skin to liquid form, sweating does not relieve from overheating. The workers of hot shops for the day is given up to 12 liters of sweat. The body is cooled at 6.5 thousand large calories. This loss of water should be compensated for drink, and for preserving normal osmotic pressure of fabrics, as already mentioned, should be introduced and salt.
Therefore, the sweat glands are important not only as an organ allocation, but also as a powerful means of combating the overheating of the body. By the way, the blood vessels of the skin also perform a number of functions. They supply the skin tissue everything necessary for metabolism, and deposited by the blood, and are involved in thermoregulation , due to the increase or decrease of blood contact with the surface of the body (through expansion or narrowing of a vascular channel), and liquid delivery to the sweat glands. The design of the body is very interesting. On the one hand, there is redundancy, increase system reliability. Remember about 7 degrees of freedom hands against the trunk or on mutual assistance and interchanging of the enzymes of the digestive tract! On the other hand, one authority, or the item is used extremely efficiently, performing in the body several things at once.
Metabolic function of the skin, its participation in the metabolism of the body, is another duty of the skin while has been studied rather poorly. Those chemicals that occur in the skin in the process of vital activity, are not indifferent for an organism and are a group of so-called physiologically active substances, which, like vitamins, included in the metabolic processes in other organs and tissues. Therefore, the skin is closely connected with many processes in our body.
Finally, we turn to the most important protective function of the skin. About it it is necessary to talk separately.