The kidneys are a pair main body of the excretory system.

the structure of the kidney
Fig. 1. The right kidney adult (rear; part substances kidney removed, sinus buds opened): 1 small Cup; 2 - fibrous capsule kidneys; 3 - large cap; 4 - the ureter; 5 - pelvis; 6 - renal vein; 7 - the renal artery.

Anatomy. The kidneys are located on the back wall of the abdomen on the lateral surfaces of the spine at the level of XII thoracal - III of the lumbar vertebrae. The right kidney is usually slightly lower left. The kidneys have Bobovdol form, with the concave side facing inwards (towards the spine). The upper pole of the kidney closer to the spine than the bottom. On its inner edge are the gates of the kidneys, which includes the renal artery coming from the aorta and out renal vein, which flow into the inferior Vena cava; from the renal pelvis moves the ureter (see). Parenchyma buds covered with dense fibrous capsule (Fig. 1), on top of which is fat capsule, surrounded renal fascia. The rear surface of the kidney adjacent to the rear wall of the abdominal cavity, and the front covered by the peritoneum and, thus, are fully nabroshena.
The renal parenchyma consists of two layers - cortical and brain. Cortical layer consists of renal cells, educated renal glomeruli, along with capsule Shumlyanskiy - Bowman, cerebral layer is made up of tubules. Canals form a pyramid kidney ending renal papilla opening in small cups. Small cups fall into 2-3 larger cups, make up the pelvis.
Structural unit of the kidney is the nephron, consisting of a ball formed blood capillaries, capsules Shumlyanskiy - Bowman surrounding the ball, convoluted tubule, Genle hinges, direct tubules and collecting tubes flowing into the renal papilla; total number of nephrons in the kidney to 1 million
In the nephron, the formation of urine, i.e. the allocation of metabolic products and toxic substances, regulation of water-salt balance of the body.
In the cavity of the glomeruli liquid coming out of the capillaries, similar to blood plasma, per 1 minute it is allocated about 120 ml - primary urine and pelvis 1 minute 1 ml of urine. When passing through the tubules of the nephron is reabsorption of water and the allocation of toxins.
In the regulation process of urine formation participate nervous system and glands of internal secretion, mainly the pituitary gland.

Kidney (lat. ren, gr. nephros) - paired organ allocation, located on the back wall of the abdominal cavity on each side of the spinal column.

Embryology. Kidney develop from mesoderm. After the stage of predpochli (pronephros) nephrotomy almost all body segments are combined symmetrically to the right and to the left in the form of two primary kidney (mesonephros), or Volfovich bodies that are not subject to further differentiation as organs of excretion. Urinary canals in them merge, discharge tubes form the left and right of common (or volfova) ducts, Windows that in the urogenital sinus. On the second month of fetal life occurs final kidney (metanephros). Cellular beams into the renal tubules. They formed the double wall of the capsule surrounding vascular glomeruli. The other ends of the tubules to converge with tubular outgrowths of the renal pelvis and open in them. Capsule and stroma P. evolve from the outer layer of the mesenchyme of nephrotoma, and renal calyx, pelvis and ureter from diverticulum volfova duct.
By time of a birth of the child's kidneys have lobed structure, which disappears to 3 years (Fig. 1).

Fig. 1. The gradual disappearance of embryonic delicately kidneys: 1 - kidney child 2 months; 2 - kidney baby 6 months; 3 - kidney child 2 years; 4 - kidney child 4 years; 5 - kidney child 12 years.

Fig. 2. The left kidney adult front (1) and rear (2).

The kidney has the form of big Bob (Fig. 2). There are convex lateral and concave medial edge of the kidneys, the front and back surfaces of the upper and lower the poles. With the medial side spacious deepening - sinus P. - open the gate (hilus renalis). Here are the renal artery and vein (a. et v. renalis) and the ureter, continuing in the pelvis P. (pelvis renalis) (Fig. 3). Lying between them lymphatic vessels interrupted lymph nodes. On vessels covered renal nerve plexus (printing. Fig. 1).

the structure of a human kidney
Fig. 1. Renal nerve plexus and regional lymph nodes with discharge renal lymph vessels (left kidney cut on the frontal plane): 1 - diaphragma; 2 - esophagus (cut); 3 - n. splanchnicus major sin.; 4 - capsula fibrosa; 5 - pyramides stones; 5 - columna renalis; 7 - medulla renis; 8 - cortex renis; 9 - m. quadratus lumborum; 10 - calyx renalis major; 11 - pelvis renalis; 12 - nodi lymphatici; 13 - hilus renalis dext.; 14 - gangl. renalia (plexus renalis); 15 - gl. suprarenalis; 16 - v. cava inf. (cut).

Fig. 2A and 26. The zone of contact between the right (Fig. 1A) and the left (Fig. 16) kidney with the neighbouring organs: 1 - adrenal area; 2 - duodenal region; 3, 4 and 7 of the colon and intestinal area; 5 - liver area; 6 - splenic area; 8 - codecision area; 9 - pancreatic area; 10 - gastric area. Fig. 3. Arrangement of blood vessels in the kidney: 1 - capsula fibrosa with blood vessels; 2 - vv. stellatae; 3 - v. interlobularis; 4 and 6 - vv. arcuatae; 5 - loop, Genle; 7 - collecting duct; 8 - papilla renalis; 9 and 11 - AA. interlobularis; 10 - AA. et vv. rectae; 12 - a. perforans; 13 - a. capsulae adiposae.

The rear surface of the kidney (facies posterior) lies closely to the posterior abdominal wall on the border of the square of the muscles of the lower back and lumbar muscles. In relation to the skeleton P. occupies the four vertebrae (XII breast, I, II, III lumbar). The right kidney is 2-3 cm below the left (Fig. 4). Top P. (extremitas superior) as would be covered by the adrenal gland and is adjacent to the diaphragm. Kidney lies behind the peritoneum. With the front surface of the kidney (facies anterior) contact: right - liver, duodenum and colon, left - stomach, pancreas, part of the spleen, small intestine and descending colon (printing. Fig. 2A and 26). P. covered with dense fibrous capsule (capsula fibrosa), which sends the parenchyma of the authority bundles of fibers. On top of the fat is located capsule (capsula adiposa), and then renal fascia. Sheets fascia front and rear are converging on the outer edge; medial they move through the vessels to the median plane. Renal fascia captures the kidney to the posterior abdominal wall.

sellotape kidney
Fig. 4. Sellotape kidney (with respect to the spine and two bottom edges; rear view): 1 - the left kidney; 2 - aperture; 3 - XII edge; 4 - IX rib; 5 - parietal pleura; 6 - the right kidney.

Fig. 5. Forms of the renal pelvis And ampullary; B - dentrifica; 7 - Cup; 2 - pelvis; 3 - the ureter.

The renal parenchyma consists of two layers - outdoor, cortical (cortex renis), and internal brain (medulla renis), which offers more bright red color. Cortical layer contains kidney cells (corpuscula renis) and is divided into segments (lobuli corticales). Cerebral layer consists of direct and collecting tubules (tubuli stones recti et contorti) and is divided into 8-18 pyramids (pyramides stones). Between the pyramids are drawn renal posts (columnae stones), which separates the share P. (lobi stones). The tapered part of the inverted pyramid in the form papilla (papilla renalis) in the sine and penetrated 10-25 holes (foramina papillaria) the collecting ducts, Windows that in small cups (calices stones minores). Up to 10 of these cups are combined in 2-3 large Cup (calices stones majores), which become the renal pelvis (Fig. 5). In the wall of the cups and pelvis are thin muscle bundles. Pelvis continues into the ureter.
Each kidney receives a branch of the aorta, renal artery. The first branch of this artery are called segmental; their 5 according to the number of segments (top, front, top, middle, front, back and bottom). Segmental arteries divide into magdalenae (AA. interlobares renis), which are divided into arcuate arteries (AA. arcuatae) and magdalsophia artery (AA. interlobulares). Magdalsophia artery give arterioles, which branched into capillaries that form renal glomeruli (glomeruli).
The capillaries of the ball then re-assembled into one carrying blood to the arterioles, which soon divided into the capillaries. Capillary network of arms, I. E. the network between the two arterioles, called wonderful network (rete mirabile) (printing. table, Fig. 3).
Venous bed kidney occurs as a result of merge of capillaries. In the cortical layer formed star Vienna (venulae stellatae)where the blood enters magdalsophia Vienna (vv. interlobulares). In parallel arcuate arteries curved stretch of Vienna (vv. arcuatae)that collects blood from mitakovich veins and from direct venules (venulae rectae) brain matter. Arched Vienna moving in Magdalene, and the last in the renal vein, which flows into the inferior Vena cava.
Lymphatic vessels are formed from plexus lymphatic capillaries and blood vessels of the kidney, out in the field of the gate and into the adjacent regional lymph nodes, including Prearalie, paranormalnye, retrocaval and renal (printing. Fig. 1).
Innervation kidney comes from renal nerve plexus (pl. renalis), which come efferent vegetative conductors and afferent nerve fibers of the vagus nerve, as well as the processes of the cells of the spinal nodes.