Anatomy and function of the human kidney

Usually interested in where the kidneys, people begin with the appearance of lower back pain. With this symptom, the doctor will require a urine test. The result helps in the differential diagnosis of pain in the back.

In the study of the anatomical and physiological characteristics of a person of great importance to the excretory functions. Not getting rid of processed products of tissue destruction, unnecessary slag substances, the body could not exist. Brain cells are very sensitive to different kinds of intoxication.

The correct anatomy of the kidneys and urinary tract helps to support the composition of the blood, and hence provide power to all organs.

What you need to know about the structure of the kidney?

Every healthy person has two kidneys. This can be attributed to these bodies to guys. They are located on two sides of the spine. The boundaries of the upper and lower renal poles lie at the level of the third lumbar to the twelfth thoracic vertebrae. The upper edge of the adjacent they are closer to the spine. The right kidney is located 2-3 cm below the left.

The shape of the body resembles a bean or a bean. The gates (the entrance and exit of vessels, nerves, the ureter from the pelvis) of the kidney is located on the inside, dragged the side of “Bob”. The weight of each body does not exceed 200 g. the Outside covered with a densified first fibrous sheath (capsule), then the layer of fat and special fascia. When stretching or increase in the kidneys a person has a sore lower back, because the sensitive nerve receptors in the capsule.

Its leaves (front and rear) fascia is fused in the region of the outer edge. On the inner surface, they form a receptacle for the vessels. The role of fascia fixation of the kidney to the abdominal wall.

Ratio with neighboring organs

Relationship to anatomical structures of the body forms a topographic picture of the internal organs. It has value in the diagnosis, surgical intervention. Knowledge and experience replace the surgeon a 3D image on the screen.

In relation to the peritoneum of the kidney in contact front and back surface, but are extraperitoneal.

Anterior to the right kidney located:

  • liver,
  • the intestine (duodenum and colon).

On the left are:

  • stomach
  • part of the spleen,
  • pancreas,
  • the small intestine and the descending division poperechnopolostah.

On both tops of the “sit” covered with fat tissue and the adrenal glands. Above them rise the dense muscle of the diaphragm.

Behind the location of the kidney is bordered by the abdominal wall in the area of the largest muscles of the back (lumbar and square).

What is the parenchyma?

The inner part of the incomplete organ is called the parenchyma. It consists of fabrics that provides the main functionality of the kidneys in the human body.

The cut renal parenchyma is represented by two layers:

  • the bark looks darker, structurally divided into slices that contain the renal corpuscle;
  • the brain substance is on the inside, bright red color, composed of pyramids (8 to 18), between them there is a dividing pillars that differentiate between a fraction.

In the structure of the wall of the cups and the pelvis of the kidney included muscle bundles

The narrow part of the pyramid is directed into the cavity (sinus), where each forms a papillae and 10-25 holes. Through them at the collective ducts urine is directed into small cups (10), then in 2-3 large size, and then directly into the main collector – renal pelvis. The bladder is connected with the kidney by the ureter.

Features of the kidneys in pregnancy

In women during pregnancy the enlarged uterus displaces the internal organs of the abdominal cavity. The increased load on the urinary organs leads to stagnation, the expansion of the pelvis and ureters. The changes most pronounced to the right. It depends on the deviation of the pregnant uterus from the second trimester. In the result, the right ureter is pressed to the bones of the pelvis, and the left – moving front.

Have a certain value:

  • swelling of the ureter, narrowing of their lumen;
  • forming an acute angle at the confluence into the bladder.

Photo ultrasound picture of kidney allows to detect deviations

Features are not a pathology, but contribute to the risk of inflammatory diseases of the kidneys and formation of stones.

Structural unit and its work

In anatomical structure of human kidney, the main unit is the nephron.

It can be easily represented as:

  • the tangle of blood of the finest capillaries is covered with a capsule, called by name the scientists who described it – Shumlyansky-Bowman;
  • convoluted tubules;
  • straight tubules;
  • loop of Henle;
  • collecting ducts.

Anatomy and physiology of the kidneys are provided with a million of such entities.

The glomeruli lie in the cortical layer, and the tubules – in brain, a collecting tube together and fall into a hole papillae

It is in the nephron does the process of urine formation. Here the blood leaves unnecessary substances, decomposition products of, foreign agents. On its proper operation depends on the support of the balance of salts and water.

It is established that in one minute the kidneys are processed in glomeruli of approximately 120 ml of primary urine. From it enters the pelvis 1 ml, because, passing through the tubules of the fluid absorbed back. Are subject to removal only slag material.

During the day, the volume of processed blood comes to thousands of liters. It is estimated that for the moment receives the same amount of blood in the lower extremities and kidneys. But the intensity of work per unit weight of the kidney is almost 20 times greater than that of the main bodies. Compared to the minute volume of the left ventricle of the heart kidneys themselves passed through ¼ of his load.

The job of the nephron is regulated by the nervous and endocrine system. The most influential gland is the pituitary gland.

Peculiarities of blood supply

Anatomy of the kidney should be complemented with the study of blood supply and innervation of an organ. From the abdominal aorta leave the left and right renal artery.

The mouth is represented by the branches:

  • the first row segment are called according to the number of five segments (lower, rear, middle-front, front-top, top);
  • second row – interlobar artery;
  • the third row is curved;
  • fourth – interlobular.

Interlobular – the most subtle form the glomeruli of the nephron. Between the two glomeruli the network is formed, which is called “miraculous.”

By capillaries merge to form venules. In the cortical layer of the kidneys are the stellate veins, for them the blood flows into the interlobular vessels. Together with the arcuate arteries are of the same vein. They collect waste venous blood from the brain substance. Then the flow is directed into the interlobar, of kidney and reaches the inferior Vena cava.

Lymph leaves by special vessels through the renal gate and into the lymph nodes.

In its location relative to the primary arterial and venous trunks, they are divided into:

  • renal,
  • Prearalie,
  • retrocaval,
  • para-aortic.

The connection with the nervous system through special renal plexus, which receives signals from the branches of the vagus nerve and paravertebral nodes.

The mechanism of

The mechanism of formation and output of urine involves all possible functions. The correctness of the location of the kidneys depends on the realization of the physiological mechanisms of the activities of the authority.

Of vascular plexus in the cavity of the ball comes a part of blood plasma. Along with it from the blood stream out of organic and inorganic substances with a certain molecular size.

Filtering is provided by the pressure difference in the capillaries and the glomerular capsule. The composition of the fluid inside the glomeruli similar to those in plasma.


  • sodium salt,
  • phosphates,
  • glucose,
  • urea,
  • creatinine,
  • uric acid and its compounds.

The tubular epithelium has functions:

  • excretion – the plasma are extracted from certain substances and excreted in the primary urine;
  • reabsorption – in the initial section of the lumen are absorbed back into the blood useful human products (e.g., glucose, 80% sodium and chloride), partially delayed urea.

After this action the amount of liquid abroad, “filter” is only about 1/8 of the received by the glomeruli.

The ability to concentrate urine composition endowed with the upward and the downward knee of the loop of Henle, they can increase the amount of printed matter in 7 times

The final composition of urine is formed in the end segments of the tubules and collective tubules. Here there is an active absorption process (determine and output of chemicals at desired concentration).

Leadership role in support of the activity of the kidneys belongs to the nervous system and endocrine organs.

The physiological functions of the kidneys

The most well-known excretory function, or excretion of unnecessary substances relating to:

  • the final products of tissue breakdown and death of cells, an example can be nitrogenous substances (urea, creatinine, uric acid);
  • excessive number, resulting in the intestinal absorption (water, hormones, vitamins, organic acids);
  • foreign agents that pose a threat to the organism (nicotine, drugs).

Kidney is not a simple output, but regulate the content of necessary substances in the blood, increasing or decreasing their concentration depending on the needs of the body. This function is called the support of internal homeostasis.

We can distinguish the types:

  • water,
  • salt,
  • acid-alkaline.
How is participation in the exchange vodnosolevy solutions?

To quantify water and salt solutions into two spaces:

  • within cells;
  • in the intercellular layer.

Their movement is in the direction of greater osmotic pressure (high concentration of solutes). Kidneys affect this process by changing the composition of the main ions due to the ability to reabsorption of the glomeruli and tubules.

Every day in the glomeruli, receive up to 600 grams of sodium, but its selection is only a few grams. 85% reabsorbed in the tubules primary. For sodium is followed by water molecules.

This process is regulated by the hormone aldosterone by the adrenal glands. In its absence, the urine is high in sodium, and the blood is determined by hyponatremia.
The special role of the kidneys in the regulation of the output of sodium is taken into account in the pathogenesis of many diseases and creating medicines

The acid-alkaline balance in the body is supported by a specific composition of the hydrogen molecules and hydroxyl groups of the alkali. This deals with a buffer system. The kidneys are able to remove or delay the necessary components and maintain the balance between these reagents.

A similar mechanism operates upon receipt of certain foods. For example, the use of significant amounts of meat leads to an increased formation of acid substances (phosphate, sulfate). Therefore, they pass into the urine, and the test will show acidic composition. A plant-based diet vegetarians delays in the blood cations of sodium and potassium, urine becomes alkaline.

Acidosis – acidification of the blood is often accompanied by pathological changes. Kidneys are actively involved in the fight with him on their own.

To do this:

  • there is a replacement of sodium ions in acidic residues (hydrogen, HCO3), with the participation of the enzyme karboangidrazy, sodium is returned to the blood and podslushivaet it;
  • increasing the synthesis of ammonia using the enzyme glutaminase and glutamatdekarboksilazy;
  • together with the liver is provided by gluconeogenesis, by which blood leaves an acidic substance (pyruvate, lactate) and converted to glucose.

The mechanism is vital if acidosis given myself a fan of fasting. Insufficient carbohydrates leads to accumulation of ketone bodies, sekikawa blood. While aktiviziruyutsya renal gluconeogenesis. In the case of complete starvation up to half of glucose is synthesized in the kidneys.

Alkalization (alkalosis), in contrast, inhibits all the reactions of gluconeogenesis and enhances the contents of pyruvate and lactate.

How do kidneys participate in other types of metabolism?

The kidneys are directly or indirectly involved in protein, carbohydrate and fat metabolism types.

Here are synthesized:

  • renin;
  • erythropoietin;
  • kinins and prostaglandins;
  • activated vitamin D3.

Using these substances affect the kidneys:

  • the regulation of blood pressure;
  • the exchange of phosphorus and calcium;
  • blood clotting;
  • the production and ripening of cells of the erythrocytic series.

The active form of vitamin D3 is formed by final reaction (after hydroxylation in the liver) oxidation of vitamin-a precursor. Thus the kidneys affect the process of calcium-phosphorus metabolism in the body. Consequence of violation are signs of bone tissue destruction (osteodystrophy) with kidney failure.

From the definition of erythropoietic hormone (factor) depends on the impact on stem cells of the bone marrow and formation of blood cells – erythrocytes. The process is activated when oxygen deficiency, is therefore part of a compensatory reaction. But in the case of inferiority of the kidneys patient anemia is formed.

Proteins synthesized in the kidneys, are the components:

  • coagulation system;
  • fibrinolysis;
  • complement.

Renin is produced by cells of the glomeruli (juxtaglomerular). It is a proteolytic enzyme that turns angiotensinogen to angiotensin I. Further, it is formed from angiotensin-II.

This substance:

  • stimulates the production of adrenal hormone – aldosterone;
  • has a vasoconstrictor effect.

By delay of sodium and water increases blood volume, the result blood pressure rises.

The synthesis of renin is increased in conditions of an ischemia of kidneys

In a state of shock response helps to maintain blood pressure. On the background of kidney disease often recorded symptomatic hypertension that is difficult to relief.

The production of kinins and prostaglandins helps to reduce the pressure.

To participate in protein metabolism include the function of cleavage of some peptides to amino acids and a delay in the blood. They then undergo the recycling of other bodies.

Where the kidneys take the energy?

Numerous tasks require kidney considerable amount of energy. To obtain the ATP, you need a good supply of oxygen.

Healthy kidneys consume up to 10% of the total blood oxygen, although by weight they make up just one percent of the total weight.

In the reaction of ATP synthesis are used:

  • fatty acids;
  • glucose;
  • ketone body;
  • proteolytic enzymes;
  • the ability of gluconeogenesis.

From the above examples we can see how the function of the kidneys depends on the structure, provision of blood, receiving “orders” from hormones and neural stimuli. Modern hearing AIDS hemodialysis (artificial kidney) overlap with only part of the functions, they are not able to completely replace the organ.

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