A brief anatomical and physiological characteristics of the kidney
The kidneys are paired organs. Externally, they resemble the shape of legumes. Located on both sides of the spine, in the area of 11-12 thoracic and lumbar vertebrae 1-2. The average body size of not more than 12 cm in length and 3-5 cm in thickness. Their concave surface facing to the vertebral column, respectively, convex - from him.
The basic functioning of the kidneys can be summarized as follows. Renal artery after "entry" in the body begins to branch into several branches. They are in the processes of tissue and penetrate into the brain substance. Here they are pided into smaller vessels to arteriolar dimensions that go into the nephron. There's even more at the expense of the small branch, they form a vascular tangle. Due to the tight encirclement of its special cells (podocytes) here comes the primary filtration of blood. Further in venules resemble only blood cells, some plasma and some proteins.
All the rest, and it wastes, electrolytes, carbohydrates, lipids and some proteins blocking filters podocytes and together with a part of the plasma fall into the tubules of the nephron. This is called primary urine. It accumulates in the cup-Bowman Shymlanskaya that semicircle surrounds vascular glomerulus. Its base - is the beginning of a renal tubule. According to it, the primary urine enters the tubule, which is long enough that it comes from the brain substance in the pyramid. Here he makes a loop and "rises" in the medulla.
All along the way he thickly shrouded in the veins extending from the outflow of the vessel. It is necessary for the reabsorption (reuptake) proteins, lipids, carbohydrates, electrolytes and some water. As a result of the renal tubules cup fall only slags, electrolytes and a part of water. This is called secondary urine. She goes to the pelvis, so we see the ureter.
It is important! A person is normally formed up to 180 liters of primary urine a day. Of this amount, about 90-95% is reabsorbed. Thus, the daily volume of secondary urine does not exceed 2 liters. One can only imagine how many organic molecules passes through the kidneys. This fact gives a clear explanation why metabolic disease often affects the kidney.
The mechanisms and causes of malnutrition
Common to all types of dystrophies is the initial stage of development. He is as follows:
Violation exchange groups of molecules.
Excessive accumulation of these molecules in the body cells.
A further mechanism varies depending on the specific type of dystrophy. But on this will be discussed below. As for the causes of dystrophy, they are pided into two large groups.
Congenital dystrophy. Due to genetic and / or birth defects at any stage of substance metabolism: from synthesis to decay. For kidney, congenital dystrophy of the most characteristic violations of protein and fat metabolism.
Acquired dystrophy result from alterations in the metabolism of any stage of the substance under the influence of external factors. The most likely causes are considered viral infections, chronic bacterial infection, radiation, chronic toxicity, as well as some diseases. These include diabetes , some tumors, trauma.
It is important! All kidney degeneration can be pided depending on the causes of and the specific substance. In the first case the diseases are pided into dystrophy congenital and acquired. But the more correct from the point of view of practical medicine is considered to be the pision by types of substances dystrophies.
Granular dystrophy. It develops as a result of intracellular edema, and release of protein into the cytoplasm. But because the protein is not soluble substance in the cytoplasm, it forms a kind of "grain." Therefore, granular degeneration of the kidneys, and got its name.
Hyaline droplet degeneration. It is the result of further development of the first kind. Here, the protein molecules by a significant accumulation begins to merge into a kind of "drops" chondroid consistency and color. In its structure, the formation of these protein resemble hyaline - the main protein "building blocks" of cartilage. This explains why hyaline droplet degeneration of the kidneys got its name.
Cornea degeneration. Develops when excessive accumulation of keratin. This white is normal characteristic only of epithelial cells. But in the case of constant exposure to the epithelial cell is not damaging factor from the cytoplasm to the fibrils begins "assembly" of the molecules of keratin.
Hydropic dystrophy. A special kind of protein dystrophy. It occurs when excessive increase in water cell vacuoles. Most often it occurs in the cell one giant vacuole containing clear liquid. In this case, the other organelles virtually none. Including the lack of core that collapses this vacuole. The main cause of malnutrition - a viral infection. For kidney structures of this type are most characteristic of the tubules. However, hydropic degeneration of the epithelium of kidney tubules is caused not so much by viral infections, but chronic inflammation in general.
Fatty degeneration or lipidoses. There are a few less. Moreover, they are often acquired character, than protein. Which equally characterized that and other embodiments. And one of the main factors of steatosis is considered ischemia - lack of oxygen. This is well illustrated by the fact that the fatty degeneration of the kidneys is often observed in chronic infections and intoxications some inorganic substances: arsenic, bismuth, mercury, and chronic alcoholism.
Carbohydrate dystrophy less characteristic for kidney. This is largely due to the fact that the kidneys play a small role in the metabolism of carbohydrates. However, under some kidney diseases Carbohydrate dystrophy can occur quite often. It is based on the deposition of carbohydrate molecules in their abundance. The most striking example of this type of diabetes is malnutrition.