The prestige of the nephron

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How jealous lean, lean neither looks people, 60 percent of its mass is, alas, water. Because she truly universal solvent, indispensable participant of the myriads of reactions that occur in living tissue. A person weighing 70 kilograms, 28 liters of water absorb cells, more than 3 liters circulates through the blood vessels and approximately 11 liters holds extracellular, tissue fluid. Of course, it is not distilled water, and the solution of salts, alkalis, carrying many substances that are born, collapsing in the cells that serve them with fuel, construction material, managers-managers, narodnymi, and performs many other works, of which interwoven dimensions of the organism vital activity.
All this biochemical ocean and flexible and stable. Changing things in each moment, he must have continuity of its basic parameters. Deviations are permissible in a very minor extent.
The most sociable liquid our body - plasma, the liquid part of blood. She maintains contact with the juices of all organs and tissues, responds to all done in them biochemical and biophysical processes. Plasma absorbs and solutions, absorbed in the digestive tract. It is easy to imagine how fluctuations affected its composition and what is required is a complex technology, to keep it constant. The main productive unit of this multicomponent cycle - buds. They implement the plan and on the shaft and in the nomenclature.
The plan on the shaft requires that the body does not know any of floods or droughts. The objective reasons are not taken into account. But we that we teas, eat cold food, work up a sweat, losing litres of fluid; and then - in the heat - those most litres tumbling down the skin, serve our mechanisms of thermoregulation.
But if the kidneys had to work only as a stopper in the gateway! There, upon the command of the Central nervous system, they are required either to prevent excessive leakage dissolved in the plasma salts, or remove the excess. This job kidneys perform virtually no backup. They are able to allocate urine, which is the concentration of salts can be compared with blood 4 times and 6 times less. That's what their functionality!
The salts dissolved in the plasma, two personalities exist to treat them particularly helpful.
Let's start with the fact that salt carry out the osmotic pressure, retaining and attracting the water. They act together. Their individual characteristics are of little interest to those parts of the brain that control the hydraulic structures, their plan on the shaft. The higher the concentration of salts in solution, the more the osmotic pressure. Where it is more - there rushes water and with it the desired cells substances. The membrane of the cells is a semi-permeable membrane, easy to overcome for water. Movement between intra - and extracellular fluid depends mainly from which side of the membrane higher osmotic pressure. If the concentration of salts in the extracellular fluid is reduced, then there will fall osmotic pressure, and water will rush into the cells, flood them, paralyzed. If the concentration of salts in the extracellular fluid is unacceptable deviates from the normal mark is not down, and up - will happen to the other problem. Stop or drastically reduced diffusion in cells pods and, consequently, the supply everything they need for life and work.
It remains to add that the salt concentration in the plasma depends on their total number and povnovodnosti ocean that bathes the cells. That's the reason for the body it is important to have a certain ratio of water and salt - water-salt balance. To control him on many key positions placed vigilant sentinel - osmoreceptors, signaling the slightest fluctuations of osmotic pressure, shear water-salt balance. It is they, osmoreceptors, set the pulse system of self-regulation, due to which in a healthy, functioning organism water balance of salt" always converges. And based on all the flawless work of kidneys.