The Kidney structure anatomy


Kidneys are the paired major organ of the excretory system of man.

Anatomy . The kidneys are located on the back wall of the abdominal cavity along the lateral surfaces of the vertebral column at the level of the XII thoracic - III lumbar vertebrae. The right kidney is usually located slightly lower than the left kidney. The kidneys are bean-shaped, the concave side facing the inside (to the spine ). The upper pole of the kidney is closer to the spine than the lower pole. On the inner edge of it there are the gates of the kidney, into which the renal artery going from the aorta enters, and a renal vein flows into the lower vena cava; the ureter leaves the renal pelvis (see). The kidney parenchyma is covered with a dense fibrous capsule (Figure 1), on top of which is a fat capsule, surrounded by a renal fascia . The posterior surface of the kidney is adjacent to the posterior wall of the abdominal cavity, and in front are covered with the peritoneum and, thus, are located completely extraperitoneally.

bud structure
Fig. 1. The right kidney of an adult person (behind, part of the kidney substance is removed, the sine of the kidney is uncovered): 1 - small calyx; 2 - fibrous capsule of the kidney; 3 - large calyx; 4 - ureter; 5 - pelvis; 6 - renal vein; 7 - renal artery.

The kidney parenchyma consists of two layers - cortical and cerebral. The cortical layer consists of renal corpuscles, formed by renal glomeruli together with the capsule of Shumlyansky-Bowman, the medullary layer consists of tubules. The tubules form pyramids of the kidney, terminating in the renal papilla, opening into small cups. Small cups flow into 2-3 large calyxes, forming the renal pelvis.

The structural unit of the kidney is a nephron consisting of a glomerulus formed by blood capillaries, Shumlyansky-Bowman capsules, surrounding glomeruli, convoluted tubules, Henle's loop, straight tubules and collecting tubules flowing into the renal papilla; total number of nephrons in the kidney to 1 million.

In the nephron, urine is formed, ie, the release of metabolic products and foreign substances, regulation of the water-salt balance of the organism.

In the lumen of the glomeruli, the liquid coming from the capillaries is similar to the blood plasma, about 120 ml - primary urine - are excreted in 1 minute, and 1 ml of urine per 1 minute in the pelvis. When passing through the tubules of the nephron, the water is absorbed back and the slag is separated.

In the regulation of the processes of urination, the nervous system and endocrine glands take part, mainly the pituitary gland.


Kidneys (Latin ren, Greek nephros) is a paired organ of discharge located on the back wall of the abdominal cavity at the sides of the spinal column.

Embryology. The kidneys develop from the mesoderm. After the pronephros stage, nephrotomes of almost all trunk segments are combined symmetrically on the right and on the left in the form of two primary kidneys (mesonephros), or wolf bodies, which do not undergo further differentiation as organs of excretion. The urinary canals in them merge, the outflowing ducts form the right and left common (or wolf) ducts opening into the urogenital sinus. In the second month of uterine life, the final kidney (metanephros) appears. Cellular beams are transformed into renal tubules. At their ends, double-walled capsules surround the vascular glomeruli. The other ends of the tubules approach the tubular outgrowths of the renal pelvis and open in them. The capsule and stroma of the kidneys develop from the outer layer of the mesenchyme of the nephrotomes, and the renal calyces, the pelvis and the ureter are from the diverticula of the volphic duct.

By the time the baby is born, the kidneys have a lobed structure, which disappears by 3 years (Figure 1).

Fig. 1. Gradual disappearance of embryonic lobulation of the human kidney: 1 - kidney of the child 2 months; 2 - kidney of the child 6 months; 3 - the kidney of the child is 2 years old; 4 - kidney of the child 4 years; 5 - kidney kid 12 years old.

Fig. 2. Left adult kidney in front (1) and behind (2).

The kidney has the shape of a large bean (Figure 2). There are convex lateral and concave medial edges of the kidney, front and back surfaces, upper and lower poles. From the medial side, a large depression - the sine of the kidney - is opened by the gates (hilus renalis). Here there are the renal artery and vein ( v. Renalis) and the ureter continuing into the pelvis renalis (Fig. 3). Lying between them, lymphatic vessels are interrupted by lymph nodes. The renal plexus spreads through the vessels (color Figure 1).

structure of the human kidney
Fig. 1. Renal plexus and regional lymph nodes with renal lymphatic vessels (the left kidney is cut in the frontal plane): 1 - diaphragma; 2 - oesophagus (cut); 3 - n. splanchnicus major sin .; 4 - capsula fibrosa; 5 - pyramides renales; 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 zones of contact between the right (Figure 1a) and left (Figure 16) kidneys with neighboring organs: 1 - adrenal zone; 2 - duodenal zone; 3, 4 and 7 - the intestinal zone; 5 - hepatic zone; 6 - splenic zone; 8 - jejunal zone; 9 - pancreatic zone; 10 - the gastric zone. 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 of Henle; 7 - collective duct; 8 - papilla renalis; 9 and 11 are aa. interlobularis; 10 - aa. et vv. rectae; 12 - a. perforans; 13 - a. capsulae adiposae.

The posterior surface of the kidney (facies posterior) closely adjoins the posterior abdominal wall at the border of the square muscle of the waist and lumbar muscle. In relation to the skeleton, the kidney occupies the level of four vertebrae (XII thoracic, I, II, III lumbar). The right kidney is 2-3 cm below the left kidney (Figure 4). The tip of the kidney (extremitas superior) is covered by the adrenal gland and adheres to the diaphragm. The kidney lies behind the peritoneum. With the front surface of the kidney (facies anterior) touch: on the right - the liver, duodenum and colon; on the left - stomach, pancreas, partly the spleen, small intestine and descending colon (color patterns 2a and 26). The kidney is covered with a dense fibrous capsule (capsula fibrosa), which sends bundles of connective tissue fibers to the parenchyma of the organ. Above is the fat capsule (capsula adiposa), followed by the renal fascia. The fascia leaves - anterior and posterior - grow together along the outer margin; medially they pass through the vessels to the median plane. Renal fascia fixes the kidney to the posterior abdominal wall.

kidney scelectotomy
Fig. 4. Skeletal to the kidney (relation to the spine and two lower ribs, rear view): 1 - left kidney; 2 - diaphragm; 3 - XII edge; 4 - XI edge; 5 - parietal pleura; 6 - right kidney.

Fig. 5. Forms of renal pelvis: A - ampullar; B - dendritic; 7 - calyx; 2 - pelvis; 3 - ureter.

The kidney parenchyma consists of two layers - outer, cortex renis, and inner, medulla renis, which is distinguished by a brighter red color. The cortical layer contains renal corpuscula (corpuscula renis) and is divided into lobuli corticales. The cerebral layer consists of direct and collective tubules (tubuli renales recti et contorti) and is divided into 8-18 pyramids (pyramides renales). Between the pyramids are the kidney posts (columnae renales), separating the lobe of the kidney (lobi renales). The narrowed part of the pyramid is in the form of a papilla (papilla renalis) in a sinus and is permeated with 10-25 holes (foramina papillaria) of collecting ducts opening into small calices (calices renales minores). Up to 10 such cups are combined in 2-3 large calyxes (calices renales majores), which pass into the renal pelvis (Figure 5). In the wall of the calyx and pelvis there are thin muscle bundles. The pelvis continues into the ureter.

Each kidney receives a branch of the aorta - the renal artery. The first branches of this artery are called segmental; their 5 in number of segments (apical, anterior upper, middle anterior, posterior and inferior). Segmental arteries are divided into interlobar (aa., Interlobares renis), which are divided into arcuate arteries (aa. Arcuatae) and interlobular arteries (aa., Interlobulares). Interlobular arteries give arterioles that branch onto capillaries forming glomeruli.

Capillaries of the glomerulus then reassemble in one blood-draining arteriolus, which soon separates into capillaries. The capillary network of the glomerulus, that is, the network between the two arterioles, is called a wonderful network (rete mirabile) (color table, Fig. 3).

The venous bed of the kidney occurs as a result of the fusion of the capillaries. In the cortical layer, star veins (venulae stellatae) form, from where the blood passes into the interlobular veins (vv. Interlobulares). In parallel arched arched arcuate veins (vv. Arcuatae), collecting blood from interlobular veins and from straight venules (venulae rectae) of the medulla. The arched veins pass into the interlobar, and the latter into the renal vein, which empties into the lower vena cava.

Lymphatic vessels that form from the plexus of lymphatic capillaries and vessels of the kidney, come out in the region of the gates and flow into the adjacent regional lymph nodes, including pre-aortic, paraaortal, retrocapital and renal (color Figure 1).

The innervation of the kidneys is derived from the renal plexus (pl. Renalis), where the efferent vegetative conductors and afferent nerve fibers of the vagus nerve enter, as well as the processes of the cells of the spinal nodules.