The functions of the kidneys are extremely diverse; they ensure the stable functioning of almost all organs and systems of the body.
Kidney organs
Except urinary organs excretory function also carried out by the lungs, skin and digestive organs. Carbon dioxide and, to a lesser extent, water are removed from the body through the lungs.
The digestive system removes various toxins, a slight excess of cholesterol, sodium ions, and calcium salts through bile and directly from the intestines.
Kidney structure
Body temperature is mainly regulated through the skin, and some electrolytes are also released through sweat.
By the way, it is worth noting that the qualitative composition of sweat and urine is almost the same, only in sweat all elements are contained in much lower concentrations.
We can say without a doubt that the kidney is the most complex organ in the entire urine in its structure and functions. excretory system.
That is why any disease that affects her in one way or another structural elements, entails deterioration general condition sick.
The outside of the kidney is covered with fatty tissue. Underneath it is a protective fibrous capsule. Partitions extend from it into the organ, dividing it into segments and lobules.
They contain vessels that supply blood to the kidney and nerve endings. Under the connective capsule fibrous tissue The renal tissue is located - parenchyma.
It is in the parenchyma that the main structural cells of the kidney are located - nephrons. In the structure of each nephron, a glomerulus and a system of tubules are distinguished, which, when collected together, form the collecting ducts.
They flow into the system of small and large renal calyces, which merge into one pelvis.
From there, urine flows through the ureters into bladder, it accumulates there for some time and is released through the urethra.
The process of urine formation
The main function of the kidneys is to filter blood plasma with subsequent formation of urine. Filtration occurs in the glomeruli of nephrons due to different pressures on both sides of the capsule covering the kidney cell.
During this process, water and certain substances dissolved in it pass from the blood through the glomerular membrane.
In this case, the so-called primary urine is formed; it is similar in composition to blood plasma, only such urine does not contain proteins.
It then enters the nephron tubule system. Their function is to reabsorb water and certain compounds. These are sodium, potassium, calcium, chlorine ions, vitamins, glucose, amino acids.
Nephron structure
They are excreted in the urine only if their concentration exceeds normal levels. During the process of reabsorption, final or secondary urine is formed, which is excreted from the body.
So, during urine formation the following functions of the kidneys are carried out:
- purification of blood plasma from nitrogenous metabolic products such as urea, uric acid, creatinine;
- removal of foreign toxic compounds from the body, shining example such a function is the release of substances that are formed as a result of the breakdown medicines;
- maintaining a constant volume of intercellular fluid in organs and tissues. This state is called homeostasis. It is he who provides constant support for the functions of all body systems;
- maintaining a constant concentration of electrolytes such as sodium, potassium, magnesium, chlorine and calcium;
- ensuring stable blood pressure levels;
- participation in the metabolism of proteins, carbohydrates and lipids. During the process of reverse filtration from primary urine, these compounds are reabsorbed. For example, in some cases the glucose needed to maintain various functions body, is formed in the kidneys by gluconeogenesis.
Role in the secretion of biologically active substances
The function of maintaining a constant level of blood pressure is only partially achieved through the removal of excess fluid during the process of urine formation.
Kidney pathologies
About 15% of total number Nephrons in the kidney perform a secretory function. They produce biologically active compounds that are very important for the functioning of the body - renin and erythropoietin.
Renin is part of the so-called renin-angiotensin-aldosterone system. Its main function is to ensure normal and stable blood pressure levels.
This is accomplished by regulating the tone of the vascular wall, maintaining a constant balance of sodium and circulating blood volume.
In addition to renin, the kidneys secrete erythropoietin. The main function of this hormone is to stimulate erythropoiesis, that is, the process of formation of red blood cells, erythrocytes.
The formation of erythropoietin in the kidneys is under the control of the nervous and endocrine systems body. Thus, its secretion increases with blood loss, anemic conditions, deficiency of iron and B vitamins.
This hormone is also involved in regulating blood pressure levels.
Kidney pathologies
All of the above functions are performed by both kidneys to an equal extent. Moreover, if one kidney is damaged or removed, the second can almost fully provide the body with vital functions.
Basically, persistent renal dysfunction occurs when the parenchyma and, accordingly, nephrons are damaged by inflammatory, bacterial or necrotic processes.
Most often, nephrons are affected by glomerulonephritis. This is a disease of an autoimmune nature, in which, due to a malfunction immune system its cells damage the kidney structure.
Since this disease almost always affects both kidneys, its long course or absence medical care leads to persistent impairment of almost all kidney functions.
A serious and dangerous condition for the body develops - chronic renal failure.
Another inflammatory disease, pyelonephritis, not so dangerous for the parenchyma.
Glomerulonephritis
It is caused by bacteria that enter the urine through the ascending route or, which happens much less frequently, through the bloodstream from other foci of chronic infection.
This disease is mainly limited to the pyelocaliceal system of the kidney. Impaired nephron function is possible with a prolonged and uncontrolled course of the bacterial process.
A persistent disruption of the outflow of urine from the kidney as a result of congenital or acquired anomalies in the structure of the ureter is very dangerous.
This condition is called hydronephrosis. Its danger is that long time it can be asymptomatic and detected at the stage when the kidney needs to be removed.
The process of urine formation occurs continuously, and disruption of its outflow from the kidney causes a persistent increase in pressure inside the organ.
This leads to an increase in the pyelocaliceal system, which puts pressure on the parenchyma on one side, and a poorly extensible fibrous capsule on the other.
As a result, blood circulation inside the kidney is disrupted, and this, in turn, causes gradual atrophy and then death of the nephrons.
Thus, we can summarize that the kidneys are one of the main organs of the entire excretory system of the body; a failure in their work leads to a whole cascade of extremely serious and dangerous diseases.
Therefore, at the slightest pain or discomfort in the lumbar region, sudden increase temperature in the absence of other symptoms, in no case should you postpone a visit to the doctor.
The most known function kidneys - creating urine and excreting various toxins with it. This happens due to the purification of the blood during the formation of primary urine and the saturation in the second circle of already pure blood with oxygen and other useful elements.
Not in the body extra organs, all are needed, and each of them performs several functions and works in sync with the others. A violation in one leads to failures of varying degrees of severity in other organs. What are the kidneys responsible for - keeping all tissues clean of toxins? arterial pressure Normally, the blood is saturated with the substances it needs. Hormones and enzymes orchestrate all the work. The work of the body itself is directly regulated by:
- parathyroid hormone;
- estradiol;
- vasopressin;
- adrenalin;
- aldosterone.
Kidney function is regulated by parathyroid hormone, estradiol, vasopressin, adrenaline and aldosterone.
In addition to them, the functioning of the organ is influenced by sympathetic fibers and vagus nerves.
Parathyroid hormone – parathyroid hormone thyroid gland. It regulates the removal of salts from the body.
The female hormone estradiol is responsible for the level of phosphorus and calcium salts in the blood. In small quantities female hormones are produced in men, and vice versa.
Vasopressin is produced by the brain, or more precisely by a small part of it - the hypothalamus. It regulates the absorption of fluids in the kidneys themselves. When a person drinks water and if it is in excess in the body, the activity of osmoreceptors located in the hypothalamus decreases. On the contrary, the amount of water excreted by the organ increases. If there is not enough water in the body, dehydration begins, and the amount secreted by the brain increases sharply. peptide hormones– vasopressin. Water stops being removed from the tissues. With a head injury, increased urine output is observed, up to 5 liters per day. This means that the hypothalamus is damaged and the production of vasopressin is stopped or greatly reduced.
Vasopressin regulates the absorption of fluids in the kidneys themselves
Adrenaline, known as the fear hormone, is produced. It reduces urine formation. His increased content in the blood is accompanied by swelling of all tissues, bags under the eyes.
The renal cortex synthesizes the hormone aldosterone. When it is released in excess, fluid and sodium are retained in the body. The result is edema, heart failure, hypertension. When there is insufficient production of aldosterone in the body, blood volume is reduced as a lot of water and sodium are excreted.
The functioning of the kidneys in the human body depends on the condition of the organ itself, normal operation thyroid gland, brain, heart.
The essential functions of the kidneys in the human body are:
- excretory;
- protective;
- endocrine;
- metabolic;
- homeostatic.
The main function of the kidneys is excretory
The kidney is a unique and perfect filtration station created by nature. Blood is supplied to the organ through a vein, undergoes 2 filtration cycles, and is sent back through an artery. Unusable waste in liquid form accumulates in the pelvis and is sent out through the ureter and thrown out.
The main function of the kidney is excretory, more commonly called excretory. During the first passage of blood through the parenchyma, plasma, salts, amino acids and substances are filtered out of it. When completing the second circle, most of the liquid is returned to the blood - plasma, useful amino acids, and the required amount of salts. Everything else, including toxins, uric and oxalic acid and substances unsuitable for further processing and use, is removed along with the water into the pelvis. This is secondary urine, which will be discharged through the ureter first into the bladder, then out.
Blood purification in the kidneys goes through 3 stages.
- Filtration is when all the water and elements present in it are removed from the blood entering the organ.
- Secretion – release of substances unnecessary for the body;
- Reabsorption is the return of amino acids, glucose, proteins, plasma and other substances back into the blood.
As a result, urine is formed, consisting of 5% solids and the rest liquid. When the body is intoxicated with alcohol, food and other products, the kidneys work with increased load, trying to remove as many harmful alcohols and other substances as possible. At this time, more urine is formed due to the removal of the necessary fluid from the tissues and blood plasma.
In addition to the excretory function, the rest are less noticeable, but just as important for the body. The organ regulates ionic processes and the amount of fluid in tissues, controls ionic processes, and the level of hemoglobin in the blood.
Protective - associated with the removal of foreign and hazardous substances, coming from outside:
- nicotine;
- drugs;
- alcohol;
- medications;
- exotic and spicy dishes.
The kidneys regulate ionic processes and the amount of fluid in tissues, control ionic processes, the level of hemoglobin in the blood
With constant increased load on the kidneys, they may not be able to cope with blood purification, and excretory function is impaired. Some toxins and viruses remain in the blood, causing various diseases, from poisoning to hypertension and cirrhosis.
Endocrine function is indicated by the participation of the kidneys in the synthesis of hormones and enzymes:
- erythropoietin;
- calcitrol;
- renin;
- prostaglandins.
Electropoietin and calcitrol are hormones produced by the kidneys. The former have a stimulating effect on the creation of blood by the bone marrow, in particular red blood cells and hemoglobin. The second regulates calcium metabolism in the body.
The enzyme renin regulates the volume of blood that circulates in the body.
Prostaglandins are responsible for regulating blood pressure. Therefore, when the kidneys fail, the pressure always jumps.
When the kidneys fail, the pressure always increases
The metabolic function of the kidneys is due to participation in the metabolism and breakdown of:
- carbohydrates;
- lipids;
- amino acids;
- proteins;
- peptides.
During fasting, they participate in gluconeogenesis, breaking down carbohydrate reserves. In addition, vitamin D completes its conversion into D3, the active form, in the kidneys. A lack of this vitamin leads to rickets.
Homeostatic function - regulation by the kidneys of blood volume in the body and intercellular fluid. The kidneys remove excess protons and bicarbonate ions from the blood plasma and thus affect the amount of fluid in the body and its ionic composition.
Main signs of kidney dysfunction
The kidneys are a modest organ that has no pain and bright severe symptoms. Only when sharp stones move from their place and, injuring the walls, try to come out, or block the ducts and the pelvis begins to burst with urine, pain and pain appear.
Kidneys are vital organs of the human body. Thanks to them, the process of filtering the blood and removing metabolic products from the body occurs. To understand how great their role is, you need to study their structure and functionality.
Location of the kidneys in the body
Each of a pair of organs has bean-shaped. In the adult body they are located in the zone lumbar region, surrounding spinal column. In children - slightly below the usual level. But, during the process of growth, the location of the buds returns to required level. To clearly recognize their location, you just need to lean your palms to your sides, and thumbs point up. On conditional line between the two fingertips are the desired organs.
Their peculiarity is their location in relation to each other. Right kidney located below the level of the left. The reason for this is that it is located under the liver, which does not allow the organ to rise higher. Sizes vary from 10 to 13 cm in length And up to 6.8 cm wide.
Kidney structure
The structural formation is represented by the nephron. A person has them more than 800 thousand. Most of located in the cortex. Without nephrons, it would be impossible to imagine the process of formation of both primary and secondary urine, which is ultimately excreted from the body. One functional unit is represented by a whole complex, which includes:
- Shumlyansky-Bowman capsule.
- Kidney glomeruli.
- Tubular system.
On the outside, the kidneys are surrounded by layers of fatty and connective tissue, the so-called "renal bursa". It not only protects against damage, but also guarantees immobility. The organs are covered with parenchyma, consisting of two membranes. The outer shell is represented by the cortex dark brown, which is divided into small parts, where there are:
- Renal glomeruli. A complex of capillaries that form a kind of filter through which blood plasma passes into Bowman's capsule.
- Glomerular capsule. It has a funnel shape. Filtered fluid passes through it and enters the renal pelvis.
- Canalicular system. It is divided into proximal and distal sections. Fluid from the proximal canal enters the loop of Henle, and then into the distal part. It is in this complex that reabsorption occurs useful substances and vitamins into the bloodstream.
The inner shell is represented by a light brown medulla, which includes pyramids (up to 12 units).
The blood supply to the kidneys occurs through a system of arteries coming from the abdominal aorta. The filtered blood fluid enters the vena cava through the renal vein. It is important to note that the organs themselves contain great amount blood vessels, feeding the cell. Regulation of work occurs thanks to nerve fibers located in the parenchyma.
The main role of the kidneys
The main role of the kidneys in the body is to cleanse the blood through filtration. This happens in renal glomeruli. It then enters the tubule complex, where it is reabsorbed. The process of secretion begins in the pelvis and continues in the ureter. It is surprising that more than 220 liters of blood are pumped through the kidneys every day, and up to 175 liters of primary urine are formed. And this is an indicator of how important their continuous work is.
Organ functions
The kidneys have the following functions:
- Metabolism. They are an important link in the synthesis of vital proteins, carbohydrates, and also form vitamin D3, which is initially produced in the subcutaneous layer when exposed to ultraviolet rays.
- Urination. During the day, 170-175 liters of primary urine are formed in the human body, which, after careful filtration and reabsorption, is excreted in the form of secondary urine with a volume of up to 1.9 liters. This is what helps cleanse the blood of excess fluid, salts, and toxic substances such as ammonia and urea. But if this process is disrupted, then poisoning with harmful metabolites can occur.
- Maintaining consistency of indicators internal environment . The level of blood and fluid in the body is regulated. Renal system prevents the accumulation of excess water in the body and also balances concentration mineral salts and substances.
- Hormone synthesis. Participate in the production of erythropoietin, renin, prostaglandin. Erythropoietin is the founder of blood cells that originate in the red bone marrow. As a result of the action of renin, the level of circulating blood is regulated. And prostaglandin controls blood pressure.
- Level control blood pressure . This occurs not only due to the production of the hormone, but also due to the excretion of excess water.
- Protection. Such harmful substances as alcohol, ammonia, and toxic metabolites are removed from the body.
- Stabilization of indicatorspH in blood plasma. This process is characterized by the removal of strong acids and the adjustment pH value. If you deviate from a level equal to 7.44 units, infectious infection may occur.
How important is kidney function in the body?
In the process of impaired kidney function, the body is exposed to poisoning, which causes uremia. This condition occurs when large cluster toxic substances, accompanied by a violation water-salt balance. It is manifested by edema of the upper and lower extremities.
Health risks can come from urolithiasis disease , formed at the moment high concentration insoluble salts. To avoid this, you need to monitor the health of your organs and use annual diagnostics such as urine and blood tests. It is advisable to carry out ultrasound diagnostics once every 1.5 years.
Prevention of kidney diseases
Firstly, you should avoid taking strong medications and hormone-based drugs, and pay attention to regular physical activity. To improve the functional activity of organs, it is necessary to consume at least 1.8 liters of water per day.
Herbal drinks are also useful, helping to cleanse the body of harmful metabolites. To avoid dehydration, it is advisable to minimize the amount of alcohol, carbonated and coffee drinks consumed and limit the amount of salt in the diet.
The functions of the kidneys cannot be overestimated: they are vital organs and are involved in many important processes of human life.
Three main functions of the kidneys
- Blood filtration. In the human body, the kidneys act as a blood filter and also remove excess fluid, urea, toxins, and creatinine. Over the course of the entire day, approximately 1.5 liters of blood passes through the kidneys and 0.5 liters is excreted. up to 2 l. urine.
- Maintaining water-salt balance. The kidneys regulate the levels of minerals and salts in the blood. If there is an excess of them, the kidneys help remove them from the body.
- Production biological substances. The following hormones are produced in the kidneys:
- Erythropoietin is a hormone that stimulates the uptake of vitamin B12, iron and copper by the bone marrow. An increase in this substance in the blood increases blood pressure and increases blood viscosity;
- Thrombopoietin is a protein produced by the liver and kidneys; it stimulates the number of platelets produced by the bone marrow;
- Calcitriol is a processed form of vitamin D. Acts as a regulator of potassium and phosphate metabolism. Lack of calcitriol production in a child’s body can cause rickets.
The kidneys also synthesize amino acids and easily absorbed vitamin D3 from vitamin D. This active form of the vitamin is necessary for the complete breakdown and absorption of calcium from the gastrointestinal tract.
Controlling sodium concentration in the blood
Within a month, the kidneys are able to replace daily requirement sodium This feature is important when you need to reduce the amount of salt you consume. Therefore, when patients are recommended to follow a salt-free diet, this does not harm their health in any way (but such a diet should be adhered to for no longer than 40 days and strictly under the supervision of a doctor).
Now you know what the kidneys do. It's also a good idea to know what they look like. Each of the buds weighs no more than 200 g. The buds are small in size: 10-12 cm long, 5-6 cm wide, and 4 cm thick, similar in shape to beans. The kidneys are located on the right and left sides of the spine, with one slightly lower than the other.
Nature has endowed people with such strong kidneys that even if they function at 20%, this will allow the body to maintain vital functions. Our well-being, blood composition, condition depend on the kidneys bone marrow and the body as a whole. These small but very significant organs must be protected and preserved for as long as possible.
Bud- paired organ. The function in the body is multifaceted. The structure distinguishes between the cortex and medulla. At the upper pole of each kidneys located small in size endocrine gland– adrenal gland. Kidney tissue consists of cells called nephrons, their number is colossal - millions. It is in these cells that urine is formed. Initially, plasma and water are filtered through the glomeruli. Then, as a result of reverse reabsorption, absorption of useful substances occurs, and as a result of tubular secretion, unnecessary components and products enter the urine and are excreted from the body.
The amount of urine produced and its further excretion (diuresis) depends on the activity of hormones that regulate this process. Aldosterone affects the retention of sodium in the body, and, consequently, water. Adrenaline (the main stress hormone) reduces urine production. Vasopressin, which is produced in the hypothalamus, regulates absorption processes in the kidneys. When the activity of this brain formation is disrupted, the amount of urine increases sharply. Besides hormonal regulation, activity kidney connected to the vagus nerve.
The role of the kidneys in the human body :
excretory Formation and excretion of urine, and with it substances unnecessary to the body (decomposition products, toxins, etc.);
homeostatic, i.e. aimed at maintaining internal constancy body;
metabolic, i.e. active participation in various processes exchange in the body;
endocrine, i.e. the production of various substances: calcitrol, whose function is to regulate calcium metabolism, renin - responsible for the volume of circulating blood, prostaglandins, on which blood pressure depends, erythropoietin - responsible for homepoiesis, i.e. the process of hematopoiesis in the red bone marrow.
For work kidney In standard mode, sufficient fluid intake is required. Alcohol, carbonated drinks, coffee negatively affect work kidney. Hypertonic disease, obesity, availability various diseases also not promising for kidney nothing good. Hypothermia can cause kidney diseases inflammatory in nature. Physical inactivity and metabolic disorders contribute to the formation of kidneys stones. Kidney diseases very serious. The most dangerous complication renal pathology Anuria occurs when urine excretion stops completely and the body becomes poisoned with its own decay products.
During treatment renal pathology Nutrition plays an important role; table No. 7 is assigned, the basis of which is limiting the amount of salt.
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