Histological structure of the kidney nephron of animals. Histology of the kidneys. What the patient should know and do after the histology procedure

The kidney is covered by a capsule consisting of two layers, as well as collagen fibers with a small admixture of elastic, there is still a layer of smooth muscles in the depths. It should be noted that the latter pass into the muscle cells of the veins of the stellate type. The capsule contains a large number of lymphatic and blood vessels, they are closely connected with the circulatory system not only of the kidneys, but also of the perirenal fiber. If there are problems with the urinary system, in most cases the kidney is to blame, histology will allow an accurate study of this organ.

Kidney histology is a fairly informative and accurate diagnostic measure that allows timely detection of the presence of pathologically dangerous cells. Due to the histological examination, it is possible to examine the tissues and systemic organs of the human body in more detail. The main advantage of this method is that it allows you to accurately and quickly get the result. Histology allows you to carefully study the structure of the kidneys and the entire urinary system, the study should be approached as responsibly as possible.

Renal histology is an informative and accurate diagnostic method

Modern medicine is able to provide a wide range of different diagnostic measures, with their help, the specialist has the opportunity to establish an accurate diagnosis, as well as choose the appropriate treatment in the future, which will contribute to a quick and less expensive recovery. However, some methods have a certain error, it affects the accuracy of the study. In this case, histology comes to the rescue, because it is one of the most accurate diagnostic methods.

Methodology

Previously noted that histology is the process of examining a sample of human tissue using a microscope. To study the tissue material in a histological way, such manipulations are carried out, which we will describe below:

1. The test sample is immersed in a special liquid designed to increase the density of the sample.
2. Then the material is filled with paraffin, after which it is cooled to a solid state.
3. The specialist cuts the fabric into the thinnest samples, which will allow for a more detailed study.
4. All samples are stained with a characteristic pigment.
5. The material is examined under a powerful microscope.

On a special form, the laboratory assistant fills in the data on each sample, after which he makes a certain conclusion. The process of preparing a sample for histology requires not only increased attention, but also a highly qualified specialist, which a simple laboratory assistant does not have.

You should not count on an instant result, since the diagnosis will take at least 7 days.

If the patient is urgently delivered to a specialized medical facility, then an urgent histology of the paired organ may be required, but in this condition there is no whole week of waiting, so an express test is performed. In this case, the collected resources must be frozen in order to cut the samples correctly. The disadvantage of such manipulations is that the accuracy of the result will be much lower. The rapid test is intended solely for the determination of tumor cells. The degree of damage to the body and the stage of the disease must be studied by separate diagnostic measures.

Histology is an effective diagnostic method even in the case when the blood supply to the kidney is not carried out correctly. There are several methods for conducting this research. Much depends on the preliminary conclusion that the patient was given. It should be understood that tissue sampling for research is a very important and responsible process that can only be carried out by specialists; the accuracy of diagnostics directly depends on it.

The specialist conducts control with the help of special equipment, and then inserts a needle through the skin. In an open way, kidney material is taken through surgical intervention, for example, when a tumor formation is removed or when only one kidney functions in a person. For pregnant women and children, ureteroscopy is performed. Also, this method is advisable to implement when stones are present in the renal pelvis in case of urolithiasis.

The transjugular technique is used in cases where the patient has problems with blood clotting, overweight, improper functioning of the respiratory system, or congenital defects of the urinary system, such as a kidney cyst. Histology is implemented by various methods, each of them is considered by a physician on an individual basis, based on the characteristics of the human body, which will be indicated by preliminary diagnostic measures. More detailed information can only be given by the attending physician. It should be noted that the procedure requires sufficient qualifications, therefore, only experienced specialists should be contacted. A novice in this field can cause irreparable harm to the body.

Detailed information about the procedure can only be given by the attending physician.

The procedure is carried out in a special room or in the operating room. On average, it takes about 30 minutes to take the material, while anesthesia is performed with local anesthesia. However, sometimes there are indications from the attending physician when it is advisable to use general anesthesia. In some cases, this is replaced with sedatives, under the influence of which the big one will be able to follow all the instructions of the specialist. Histology is carried out as follows:

1. A person takes a position on a hospital couch, lying on his stomach, a special roller is placed under it. In the event that the kidney was previously transplanted, then he should lie on his back.
2. The patient's blood pressure and pulse are constantly monitored. The specialist treats the place where the needle should enter, after which an anesthetic is injected.
3. It is important to note that there is practically no pain during such manipulation, some people note slight discomfort, so there is no need to be afraid to worry and be afraid.
4. In the area where the kidneys are localized, a small incision is made, where the specialist inserts a needle of small thickness. The whole process is controlled by ultrasonic waves. If the patient is under local anesthesia, then the specialist asks to hold his breath for a while so that he can safely insert the needle.
5. At that moment, when the needle got under the skin, the patient may feel increased pressure in the kidney area. At the time of sampling, you can hear an unpleasant click, but this does not cause any pain and is completely normal, so you should not be scared.
6. Sometimes a specialist may decide to administer a drug; in this case, the histology of the kidney will be much more effective. The fact is that a contrast agent is injected into the vein, it is able to show important blood vessels and the organ itself.
7. If necessary, the specialist conducts several more punctures if the material taken is not enough.
8. The specialist pulls out the needle, a bandage is applied at the site of the manipulation.

The occurrence of pain directly depends on the condition of the patient, as well as the degree of damage to the body. Another factor that affects this indicator is the professionalism and qualifications of the specialist. Almost all the likely risks of complications are associated precisely with the capabilities of the doctor.

Indications

Histology is best suited to study the structure of the kidneys. Not many people know that this method is sufficiently accurate and informative, and other diagnostic methods cannot even compete with it. However, there are several situations where histology is a mandatory procedure, without which it is impossible to carry out further treatment, since it can be life-threatening, because the attending physician does not have sufficient information.

The main indications for a diagnostic study include the following aspects:

• chronic or acute diseases;
• , localized in the urinary tract;
• the presence of blood in the urine;
• elevated uric acid;
• determination of the pathological condition of the kidneys;
• unstable functioning of a kidney that was previously transplanted;
• suspicion of the presence of neoplasms;
• determination of the stage and severity of the disease.

Histology is the study of the tissue material of the human body under a powerful microscope. Due to this method, a specialist is able to detect harmful cells or even neoplasms that are present in the human body. It is important to note that this method is one of the most accurate and effective at the moment in modern medicine. The histology of a tumor-like formation of the kidney makes it possible to detect pathology at an early stage of development, which makes patients more likely to recover and successfully rehabilitate.

Leading experts in the field of nephrology

Bova Sergei Ivanovi h - Honored Doctor of the Russian Federation, Head of the Urology Department - X-ray shock wave remote crushing of kidney stones and endoscopic methods of treatment, Regional Hospital No. 2, Rostov-on-Don.

Letifov Gadzhi Mutalibovich - Head of the Department of Pediatrics with a course of neonatology of the FPC and teaching staff of Rostov State Medical University, Doctor of Medical Sciences, Professor, Member of the Presidium of the Russian Creative Society of Pediatric Nephrologists, Member of the Board of the Rostov Regional Society of Nephrologists, Member of the Editorial Board of the Bulletin of Pediatric Pharmacology Nutrition, doctor of the highest category .

Turbeeva Elizaveta Andreevna - page editor

Book: "Children's Nephrology" (Ignatov M. S., Veltishchev Yu. E.)

The anatomical and histological structure of the kidneys clearly reflects the basic and highly specialized function of this organ. The kidneys are peculiar in form. Their mass in relation to the mass of the body is almost constant and is approximately V200 - V250 part.

In adults, the mass of each of these organs is about 120-150 g, the left kidney is slightly smaller than the right one. The kidneys are located near the aorta and are intensively supplied with blood.

Each kidney has an outer (cortical) and an inner (medulla) substance. The areas of the renal medulla that are cone-shaped are called the renal pyramids. In one kidney, from 8 to 16 pyramids are most often observed.

The structural and functional unit of the renal tissue is the nephron. It has a renal corpuscle with a complexly built vascular glomerulus (glomerulus), a system of convoluted and straight tubules, blood and lymphatic vessels, and neurohumoral elements. The total number of nephrons in both kidneys is about 2,000,000.

The sizes of nephrons and their renal glomeruli increase with age: in one-year-old children, the average diameter of the glomerulus is about 100 microns, in an adult it is about 200 microns.

There are several types of nephrons depending on localization. The main ones are superficial (cortical), mid-cortical and pericerebral (juxtamedullary) nephrons.

The nephron loop (Henle) is longer in those elements that are located closer to the medulla (Fig. 7). In the study of the kidneys of mammals, it was determined that the more nephrons with a long loop in an animal, the higher the concentration ability of its kidney tissue [Natochin Yu. V., 1982].

Juxtamedullary nephrons make up the Vi0-V15 part of the total number of nephrons. The efferent arteriole of the juxtamedullary nephrons, upon leaving the glomerulus, gives branches to the medulla, where each arteriole is divided into several parallel descending direct vessels, which go in the direction of the renal papilla and, after dividing into capillaries, already in the form of veins, return back to the cortical part, ending in interlobular or arcuate veins.

Due to their special structure, juxtamedullary nephrons are considered as elements of the kidney with special functional tasks: they provide the process of countercurrent exchange in the kidney.

The cortex of the kidneys. Renal body. This element of the nephron is formed by a glomerulus enclosed in a capsule; it is closely connected with the adjacent SGC. The glomerulus of the renal corpuscle (glomerulus) consists of a group of intertwined capillaries originating from the afferent arteriole and flowing into the efferent arteriole. Both vessels are located at the same pole of the glomerulus.

Thus, a special capillary network is formed between the afferent and efferent arterioles, which lies unusually - not between arterioles and venules, but inside the arterial system; it is called the "wonderful network".

The efferent arteriole divides into smaller branches and into ordinary capillaries only in the area of ​​the nephron tubules. As a result, the venous system of the kidney begins not from the capillaries of the glomerulus, but from the capillaries braiding the renal tubules. In the afferent arteriole in front of the glomerulus, there is a hydrostatic blood pressure of about 9.33 kPa, which provides glomerular filtration.

Modern information about the details of the structure of the renal corpuscle, its glomerulus and individual capillaries is based mainly on EM data.

The wall of the glomerular capillary consists of endothelium, BM and podocytes (epithelial cells), the outer surface of which faces the cavity of the glomerular capsule (Fig. 8).

The glomerular basement membrane (GBM) of capillaries is about 350 nm thick in adults. In children, it normally ranges from 200 to 280 nm, with congenital and hereditary renal pathology it often does not reach more than 100 nm of its normal thickness, it is less than 100 nm, and can also significantly exceed the norm. It consists of a middle, electron-optically dense layer (lamina densa) and two light layers (lamina eiderdown) on either side of the middle one.

Glomerular filtration of macromolecules depends on their size, configuration and charge. They interact with supracellular layers of glomerular polyanions located in a certain sequence (negatively charged heparan sulfate proteoglycans) and with a network of type IV collagen elements localized in the GBM [Daihin E. I., 1985; Schurer J. A., 1980; Langer K., 1985].

Anionic negatively charged sites present in the edge layers of GBM are detected by EM using polyethyleneimine; they are damaged and disappear in glomerulopathies or their experimental models.

Podocytes have many small processes - pedicles (cytopodium), by which these cells are associated with GBM (Fig. 9). In the area of ​​pedicles, slit internedicular membranes and on the free surface of podocytes, a layer of glycocalyx is found - a carbohydrate-containing biopolymer, which includes neuraminic (sialic) acid; the carrier of this acid is a protein (sialoprotein or podocalyxin), which is biochemically equivalent to GBM polyanions [Kejaschki D., 1985].

With glomerular pathology, the level of pokalixin falls, it changes ultrastructurally, loses its characteristic properties.

Endotheliocytes of glomerular capillaries over a considerable extent of the vascular wall are represented by a thin layer of cytoplasm, which has pores, due to which the blood plasma is more fully in contact with the substance of the BM glomeruli. The flat layers of the porous cytoplasm of the fenestrated endotheliocyte pass into its more massive perinuclear part.

According to immunohistochemical studies, a protein identical to podocalyxin is present in almost all endothelial cells of the body. The existence of these surface biopolymer layers is probably associated with ensuring the unhindered movement of biological fluids through the channels of various organs and systems.

In the inner part of the capillary wall, which most often faces the vascular pole of the glomerulus and does not contain BM, there is mesangium under the endothelium. Mesangiocytes are polyfunctional. They exhibit the properties of pericytes, fibroblasts, cells close to macrophages, smooth muscle and JGC cells.

By the method of cell culture of glomeruli, cells of the epithelium, contractile mesangium, endothelium, mesangium of bone marrow origin are isolated; the sites of synthesis of BM components were determined, data were obtained on the retraction of mesangiocytes and podocytes under the action of angiotensin II on their receptors.

Juxtaglomerular complex. In the wall of the afferent arteriole directly near the glomerulus, there are special cells with granules (juxtaglomerular cells, type I cells). These cells, together with an accumulation of macula densa cells (type III cells) that creates a seal (macula densa) in the adjacent distal tubule, and juxtavascular islet cells (type II cells) located between the afferent arteriole, efferent arteriole and the macula, form JGC.

It has a secretory ability, contains renin. Experimental studies show that JGC affects the level of blood pressure and the chemical composition of the ultrafiltrate in the nephron.

The functional relationships of the elements of the glomerular structure are supported by a system of small holes and channels that exist together with the layers of polyanions.

Tubules of the renal cortex. The tubules of the nephron are very heterogeneous in structure and function. Epithelial cells of the proximal part of the nephron tubule have a brush border consisting of many microvilli; a significant amount of elongated mitochondria is determined in the cytoplasm.

In acute glomerulonephritis, villi similar to motor cilia of the respiratory epithelium were found on the cells.

The distal part of the tubule is closely related to the JGC. The epithelium of the distal tubules is somewhat similar to the epithelium of the proximal part, it is also represented by large cells.

However, there are only a few microvilli on the surface of these cells, mitochondria are more abundant, but smaller in size, the cytoplasmic membrane on the basal surface has fewer folds, which indicates a different functional ability of the epithelium of the distal tubule compared to the proximal one, in particular, secretory activity.

The distal tubules without a sharp border pass into the collecting ducts (tubules) of the cortical substance of the kidney. This substance is dominated by arcuate tubules containing cells of two types - transparent and dense. Transparent cells are cuboidal, they have a large nucleus, few mitochondria.

The main function of these cells is the delimitation from the environment of the contents located in the lumen of the tubule and excreted into the renal pelvis. Dense cells contain many small mitochondria and ribonucleoprotein granules, which indicates the implementation of enzymatic processes in them.

When the collecting duct passes into the medulla, the dark cells become single and disappear, the tube becomes straight and flows into the papillary duct.

The medulla of the kidneys. The renal medulla contains straight tubules and nephron loops, collecting ducts, descending and ascending rectus vessels, and interstitial tissue.

The nephron loop (tubules of Henle) is subdivided into relatively thin-walled descending branches, including the knee of the loop, in which the direction of the tubule is reversed, and thick-walled ascending branches. Epithelial cells of the thin, descending part of the loop have a small volume of cytoplasm, small and few mitochondria, and a low number of endoplasmic membrane cells.

Cells flattened, light. This structure corresponds to the limited number and low activity of enzymes in this hypoxic zone of the renal tissue. The cytoplasm contains clefts that run through the cell body to the BM. This area of ​​the nephron is extremely permeable to water, and this is probably the main feature of this department.

The thick, ascending, part of the nephron loop is located in the outer part of the medulla. Here in the epithelium there is a basal folding of the cytomembrane, which is inherent in the cells of the adjacent distal nephron; there are also elongated, relatively large and very numerous mitochondria; the apical part of the cells is strongly vacuolized.

Such an ultrastructure of the epithelium corresponds to the cell's ability to actively transport electrolytes. It is important to note that children have shorter nephron loops than adults.

This feature is expressed the more, the younger the child; accordingly, the regulation of water-salt metabolism is less flexible in a young child [Veltishchev Yu. E. et al., 1983].

The straight collecting tubules of the renal medulla have cuboidal cells that become higher distally, the cytoplasm contains granules and a few small mitochondria; elements of the endoplasmic reticulum are poorly developed. Such an ultrastructure indicates a low energy and synthetic potential of the cells.

Interstitial cells of the kidney tissue. In the renal cortex and medulla between the tubules there are fibroblasts, macrophages, less often lymphoid and plasma cells. Special interstitial cells of the renal medulla are involved in the work of the countercurrent system of the kidneys and in the process of concentrating the contents of the tubules, and also produce prostaglandins.

There are objective morphofunctional indicators of the state of the renin-angiotensin and prostaglandin systems in pathology, in particular in nephrogenic arterial hypertension, its stage and duration [Serov V. V., Paltsev M. A., 1984].

Vessels of the medulla. They are represented mainly by thin-walled elements with parallel long descending and ascending parts, as well as a loop, which is similar to the construction of the tubules of the nephron loop.

The location of the vessels and tubules of the medulla corresponds to the existence of a countercurrent mechanism in the kidney, with the help of which the exchange of substances between the contents of the direct tubules and blood vessels is carried out.

A low blood flow velocity helps to maintain an anoxic gradient (difference), in which the blood vessels at the top of the renal papilla have the same amount of oxygen as the contents of the tubules.

Another important gradient in the renal medulla is osmotic, with the highest concentration of sodium ions, which mainly create an osmotic gradient, being reached at the top of the renal papillae.
The circulatory system of the kidneys. The kidneys receive blood through a large arterial branch - the renal artery, which departs from the aorta and is divided into 2 - 3 elements that enter the kidney and branch into the interlobar arteries.

The interlobar arteries pass between the pyramids of the kidney, “then, on the border between the cortical and medulla, they give rise to the arcuate arteries; interlobular arteries depart from the latter, deepening into the cortical substance. Here, the afferent glomerular arterioles branch off from them, disintegrating into the capillaries of the renal glomeruli.

Thus, the glomeruli are supplied with blood from relatively large arterial branches. The vessels of the venous network are located almost parallel to the arterial ones. Blood from the capillaries of the tubules is collected in the venous plexus of the cortical substance and sequentially passes through the interlobular, arcuate and interlobar veins, flowing into the renal vein, which flows into the inferior vena cava.

In the outer zone of the renal medulla, the efferent arterioles of the juxtamedullary nephrons form arterial and then venous direct vessels, which, entering the medulla, form cone-shaped bundles.

The complex histoarchitectonics of the medulla ensures the process of countercurrent exchange, which is a necessary element of the osmotic concentration of urine [Natochin Yu. V., 1982].

Lymphatic system of the kidneys. Lymphatic capillaries are absent inside the renal glomeruli, but they wrap around the renal corpuscle in a kind of basket and cover the convoluted and straight tubules. From the capillaries, when they merge, interlobular lymphatic vessels arise.

Next are the lymphatic vessels equipped with valves that accompany the arcuate arteries and veins. Enlarging, the vessels go to the gates of the kidney and flow into the lumbar lymph nodes. In the kidney, two systems of lymphatic tracts can be distinguished - cortical and papillary.

Both systems connect with interlobular lymphatic vessels. If the function of the lymphatic system is impaired, the protein of the plasma ultrafiltrate is retained in the stroma of the kidney, edema and hypoxia of the renal tissue occur, and dystrophy of the epithelium of the tubules occurs.

Innervation of the kidneys - the structure of the kidneys. The kidney is supplied with fibers of sympathetic nerves, starting from the thoracic and lumbar sections of the border sympathetic trunk between the 4th thoracic and 4th lumbar segments.

The fibers form plexuses of a complex structure, are located around the renal artery; at the places of origin of the renal arteries from the aorta are the upper and lower renal sympathetic nodes.

The renal glomeruli and tubules are entwined throughout with nerve fibers of various thicknesses; there are many fibers in the juxtamedullary zone and in the renal pelvis. Nevertheless, the denervated kidney retains excretory and homeostatic functions, which indicates a high degree of intraorganic self-regulation of renal functions.

The urinary system contains the kidneys and urinary tract. The main function is excretory, and also participates in the regulation of water-salt metabolism.

The endocrine function is well developed, it regulates local true blood circulation and erythropoiesis. Both in evolution and in embryogenesis, there are 3 stages of development.

At the beginning, a preference is laid. From the segmental legs of the anterior sections of the mesoderm, tubules are formed, the tubules of the proximal sections open as a whole, the distal sections merge and form the mesonephric duct. The pronephros exists up to 2 days, does not function, dissolves, but the mesonephric duct remains.

Then the primary kidney is formed. From the segmental legs of the trunk mesoderm, the urinary tubules are formed, their proximal sections, together with the blood capillaries, form the renal corpuscles - urine is formed in them. The distal sections drain into the mesonephric duct, which grows caudally and opens into the primary intestine.

In the second month of embryogenesis, a secondary or final kidney is laid. From the non-segmented caudal mesoderm, nephrogenic tissue is formed, from which the renal tubules are formed, and the proximal tubules are involved in the formation of renal bodies. The distal ones grow, from which the tubules of the nephron are formed. From the urogenital sinus behind, from the mesonephric duct, an outgrowth is formed in the direction of the secondary kidney, the urinary tract develops from it, the epithelium is a multilayer transitional epithelium. The primary kidney and mesonephric duct are involved in the construction of the reproductive system.

Bud

Outside covered with a thin connective tissue capsule. A cortical substance is secreted in the kidney, it contains renal corpuscles and convoluted renal tubules, inside the kidney there is a medulla in the form of pyramids. The base of the pyramids faces the cortex, and the top of the pyramids opens into the renal calyx. There are about 12 pyramids in total.

The pyramids consist of straight tubules, descending and ascending tubules, nephron loops, and collecting ducts. Part of the direct tubules in the cortical substance are arranged in groups, and such formations are called medullary rays.

The structural and functional unit of the kidney is the nephron; cortical nephrons predominate in the kidney, most of them are located in the cortex and their loops penetrate shallowly into the medulla, the remaining 20% ​​are juxtamedullary nephrons. Their renal bodies are located deep in the cortical substance on the border with the brain. In the nephron, a body, a proximal convoluted tubule, and a distal convoluted tubule are isolated.

The proximal and distal tubules are built from convoluted tubules.

The structure of the nephron

The nephron begins with the renal body (Bowman-Shumlyansky), it includes the vascular glomerulus and the glomerular capsule. The afferent arteriole approaches the renal corpuscle. It breaks up into a capillary, which form a vascular glomerulus, blood capillaries merge, forming an efferent arteriole, which leaves the renal corpuscle.

The glomerular capsule contains an outer and an inner leaflet. Between them there is a capsule cavity. From the inside, from the side of the cavity, it is lined with epithelial cells - podocytes: large process cells that are attached to the basement membrane with processes. The inner leaf penetrates into the vascular glomerulus and envelops all the blood capillaries from the outside. At the same time, its basement membrane merges with the basement membrane of the blood capillaries to form one basement membrane.

The inner sheet and the wall of the blood capillary form a renal barrier (the composition of this barrier includes: the basement membrane, it contains 3 layers, its middle layer contains a fine mesh of fibrils and podocytes. The barrier allows all uniform elements to enter the hole: large molecular blood proteins (fibrins, globulins , part of albumins, antigen-antibody).

After the renal corpuscle comes the convoluted tubule; it is represented by a thick tubule, which is twisted several times around the renal corpuscle, it is lined with a single-layer cylindrical border epithelium, with well-developed organelles.

Then comes a new nephron loop. The distal convoluted tubule is lined with cuboidal epithelium with sparse microvilli, wraps several times around the renal corpuscle, then passes through the vascular glomerulus, between the afferent and efferent arterioles, and opens into the collecting duct.

The collecting ducts are straight tubules lined with cuboidal and columnar epithelium, in which light and dark epithelial cells are isolated. Collecting tubules merge, papillary canals are formed, two open at the top of the pyramids of the medulla.

1. The state of blood supply to the cortex and medulla (diffuse or focal venous-capillary plethora, alternation of areas of weak blood filling and foci of venous-capillary plethora, the predominance of weak blood filling).

2. Violations of the rheological properties of blood (erythrostasis, intravascular leukocytosis, parietal standing of leukocytes, division of blood into plasma and formed elements, plasmastasis, vascular thrombosis).

3. The condition of the walls of the renal arteries, arterioles (thickened due to sclerosis, hyalinosis, plasma impregnation, with the phenomenon of necrosis, acute purulent or productive vasculitis) .

4. State of the interstitium (focal or diffuse weak, moderate, pronounced edema of the interstitium).

5. The state of the renal glomeruli (their structure is preserved, the glomeruli are in a state of atrophy, sclerosis, hyalinosis, with the presence of sclerosis of the Shumlyansky-Bowman capsule of varying severity, with the presence in the lumen of the Shumlyansky capsule of a homogeneous pale pink liquid and slightly granular pale pink masses).

6. The presence of foci of nephrosclerosis, productive or acute inflammation (small / medium / large-focal, pronounced diffuse, mesh type, total).

7. The presence of foci of necrosis of the renal tissue (necronephrosis), reactive cellular reaction, the degree of its severity.

7. The state of the epithelium of the renal tubules:

- protein granular dystrophy of varying severity;

- vacuolar (small / medium / large vacuolar) dystrophy (whitish vacuoles are located along the basement membrane of the tubules or in the entire volume of the cytoplasm of epitheliocytes);

— hyaline-drop dystrophy of varying severity;

- hydropic, dropsy dystrophy of varying severity, up to the maximum degree of its severity - balloon dystrophy (epitheliocytes are significantly swollen, with a pronounced enlightenment of the cytoplasm);

- necrobiosis - necrosis of individual epitheliocytes, groups of cells, whole tubules (the nuclei are not visible, the boundaries between the cells are not traced).

8. The presence of tubules in a state of nephrocalcinosis (epithelial cells are encrusted with calcium salts or there are small calcifications in the lumen of the tubules) — most often has a postnecrotic genesis, it can also be a manifestation of hypercalcemia.

Nephrocalcinosis -

1. encrustation of tubular epitheliocytes with calcium salts, most often the outcome of epithelial cell necrosis;

2. inclusions of small calcifications are visible in the lumens of the tubules (typical for hypercalcemia);

3. mixed option.

9. BIN-symptom (basal inlay of nephrothelium) — in the presence of intravascular hemolysis of erythrocytes, until the physiological change of epithelial cells of the tubules along the basement membrane, dust-like or in the form of granules deposits of golden yellow or brown pigment are located.

10. Signs of atrophy of the tubules in the form of thinning of the epithelium, expansion of the gaps (up to the foci of the "thyroid kidney").

11. The content of the lumen of the tubules (protein masses, hyaline cylinders, brown-brown pigment slags, brown-reddish myoglobin granules, desquamated epitheliocytes, fresh and leached erythrocytes, oxalate crystals in case of oxalaturia or antifreeze poisoning).

Example number 1.

KIDNEY (1 object) - in sections weakly - moderate autolysis. Foci of venous plethora. The walls of most vessels are unevenly and circularly thickened due to moderate and severe sclerosis. Diffusely in the sections there is a moderate number of small, medium-sized and large foci of dense polymorphocellular infiltration of the stroma with a predominance of the lymphohistiocytic component (productive inflammation), they show small accumulations of sclerosed glomeruli and glomeruli with moderate sclerosis of Shumlyansky's capsule, small groups of tubules in a state of severe atrophy with cystic expansion of the lumens, thinning of the epithelium up to the filiform, with the filling of the lumens with homogeneous pink colloid-like contents (foci of the "thyroid kidney"). BIN - the symptom is not traced. In one of the fields of view there is a fragment of the PCS with a dense polymorphocellular infiltration of the wall. Picture of focal polymorphocellular nephritis.

Example number 2.

KIDNEY (2 objects, to differentiate from HFRS) — diffuse pronounced venous and capillary plethora of the cortical and medulla layers, erythrostasis, diapedetic hemorrhages. In the medulla, moderate-pronounced edema of the interstitium. The glomeruli are plethoric, a few of them are sclerosed, the lumens of a large number of Shumlyansky-Bowman capsules are filled with homogeneous and slightly granular pale pink contents. Severe protein granular degeneration of the epithelium of the tubules, necrobiosis-necrosis of individual epitheliocytes and small groups of cells. BIN-symptom is not traced.

Example number 3.

KIDNEY (1 object) — in sections, uneven initial and mild autolysis, limiting the evaluation of sections. Focal pronounced venous and capillary plethora of the cortical layer, with the presence of single small-focal destructive hemorrhages without a cellular reaction. Diffuse pronounced venous, capillary plethora of the medulla, with the practical absence of autolysis in its zone, one can speak of a widespread moderate edema of the interstitium. In the stroma, there are single small foci of round cell infiltration. The walls of the arteries are circularly weakly thickened due to sclerosis. Walls of a number of arterioles with mild hyalinosis. Uneven blood filling of the glomeruli, some of them are sclerosed. BIN-symptom is not traced.

Example number 4.

KIDNEY (2 objects) — focal venous and capillary plethora of the cortical and medulla layers. In the medulla, there is a widespread moderate-pronounced edema of the interstitium. Weakly expressed sclerosis of individual vascular walls. Mild to moderate blood filling of the glomeruli, some of them with the presence of a small amount of pale pink granular masses in the lumens of the Shumlyansky-Bowman capsules. Sclerosis of single glomeruli. Severe proteinaceous granular dystrophy of the epithelium of the tubules, with necrobiosis-necrosis of individual epitheliocytes and small groups of cells. Most of the tubules with signs of mild to moderate atrophy in the form of a decrease in the height of epitheliocytes, widening of the lumen of the tubules. BIN-symptom is not traced.

Example number 5.

KIDNEY (1 object) — in the cortical layer, against the background of the predominance of its weak blood supply, individual vessels are plethoric. Focal venous-capillary plethora of the medulla. The walls of individual vessels with initial sclerosis. Weak-moderate blood supply to most of the renal glomeruli, in a number of glomeruli, a group of capillary loops of moderate blood supply. Single glomeruli are sclerosed, with the presence of sclerosis of the Shumlyansky-Bowman capsule, with moderate productive inflammation of the tissue around the glomerulus. Protein granular dystrophy of the epithelium of the tubules, necrobiosis-necrosis of individual epitheliocytes. BIN-symptom is not traced.

Example number 6.

KIDNEY (1 object) — against the background of the predominance of weak blood filling of the cortical and medulla of the kidney in some fields of vision, small foci of moderate venous-capillary plethora. The walls of the presented vessels are not changed. Weak and weak-moderate blood filling of the renal glomeruli, the structure of the glomeruli is preserved, in the lumens of a number of Shumlyansky-Bowman capsules there is a small and moderate amount of slightly granular pale pink masses. Pronounced protein granular dystrophy of the epithelium of the tubules, with the transition in most tubules to hydropic dystrophy (as a sign of shock decompensation), with necrobiosis-necrosis of individual epitheliocytes and small groups of cells. In the lumen of the tubules - protein masses, a small amount of fresh and leached erythrocytes.

Example number 7.

KIDNEY (1 object) — pronounced diffuse venous-capillary plethora of the cortical and medulla with erythrostasis, diapedetic microhemorrhages and hemorrhages. Moderately pronounced edema of the interstitium of the medulla. The walls of individual vessels with mild sclerosis. The glomeruli are significantly plethoric, a few of them are sclerosed. Pronounced and pronounced proteinaceous granular dystrophy of the epithelium of the renal tubules, with necrobiosis-necrosis of individual epitheliocytes and groups of cells, with a transition in a number of tubules to hydropic dystrophy. BIN-symptom is not traced. In the gaps of a large number of tubules, oxalate crystals ("postal envelopes", "butterfly wings", "flower", etc.). The histological picture is characteristic of ethylene glycol (antifreeze) poisoning.

No. 09-8 / XXX 2008

Table № 1

Public Health Institution

« SAMARA REGIONAL BUREAU OF FORENSIC MEDICAL EXAMINATION »

To the "Act of Forensic Histological Research" No. 09-8 / XXX 2008

Table № 2

Forensic medical expert Filippenkova E.I.

Public Health Institution

« SAMARA REGIONAL BUREAU OF FORENSIC MEDICAL EXAMINATION »

To the "Act of Forensic Histological Research" No. 09-8 / XXX 2008

Table № 3

Forensic medical expert Filippenkova E.I.

Public Health Institution

« SAMARA REGIONAL BUREAU OF FORENSIC MEDICAL EXAMINATION »

To the "Act of Forensic Histological Research" No. 09-8 / XXX 2008

Table № 4

Forensic medical expert Filippenkova E.I.

Table № 5

Specialist E. Filippenkova

To the "Conclusion of a specialist" No. XXX 2011.

Table № 6

Specialist Filippenkova E.I.

Public Health Institution

« SAMARA REGIONAL BUREAU OF FORENSIC MEDICAL EXAMINATION »

To the "Act of Forensic Histological Research" No. 09-8 / XXX 2009

Table № 7

Forensic medical expert Filippenkova E.I.

To the "Conclusion of a specialist" No. XXX 2011.

Table № 8

Specialist E.Filippenkova

Practical case. False diagnosis of antifreeze poisoning. Man, 52 years old.

LIGHT (4 objects, 1 in gauze) —

IN ONE SECTIONS (1 object) - moderate diffuse venous-capillary plethora, small areas of lung tissue with opening of reserve capillaries. Dystonia, unsharp spasm of individual vascular walls. The area of ​​the studied sections is dominated by a weak partial collapse of the lung tissue. Alveolar edema is not visible. The bronchi and pulmonary pleura are not represented in these sections.

IN OTHER SECTIONS (1 object) there is a weak blood filling of the lung tissue, the lumen of the vessels is mostly empty. Large fields of lung tissue (Fig. 10) with an indistinguishable structure, only a large amount of loose fibrin with segmented neutrophilic leukocytes in various numbers, a few fibroblasts, macrophages and hemosiderophages is visible. Fine charcoal pigmentation. The bronchi and pulmonary pleura are not represented in these sections.

IN OTHER SECTIONS (1 object) — lung tissue is not visible in these sections. A ribbon-like, deformed in the form of folds growth of fungal microflora is presented, surrounded by perifocal focal purulent-fibrinous inflammation, accumulations of brown-brown granular mass, similar to blood mixed with each other and small dark brown-brown fungal spores. Budding yeast-like cells, germ tubes, true mycelium (groups of non-branching, non-septate, pale-colored hyphae), groups of spore-bearing cells with a large number of small eosinophilic or dark brown-brown spores are visible.

OBJECT IN GAUGE - uneven blood filling of vessels with a predominance of weak and mild-moderate blood filling. In a number of vessels, leukostasis of varying severity. The lung tissue is airless due to the filling of the lumen of the alveoli with dense accumulations of segmented neutrophilic leukocytes and fibrin filaments, in the central part of the sections there is a rather large focus of the maximum accumulation of leukocytes with an indistinguishable structure of the structure of the lung tissue (abscess focus), in its zone there are dense focal accumulations of oxalate crystals elongated with rounded edges and their drusen in the form of "flowers" (see photomicrographs 1-3). Diffuse against the background of inflammation (mainly peribronchial) are small and medium-sized foci of growth of the emerging connective tissue with mild to moderate proliferation of fibroblasts, diffusely located drusen of oxalate crystals. Along the edge of the cuts, there is a fragment of the wall of a large bronchus with moderate polymorphocellular inflammation, partial desquamation of the ciliated epithelium, in the thickness of the bronchus wall, at the basement membrane there are clusters of 4-7 druse of oxalate crystals.

KIDNEY (2 objects) - uneven blood filling of the kidney tissue: a combination of areas of weak blood filling and foci of moderate venous-capillary plethora. Diffusely located small foci of nephrosclerosis with focal weak-moderate round-cell infiltration of the stroma. The walls of the vessels are unevenly thickened due to weak and mild to moderate sclerosis, some of them are in a state of dystonia, mild spasm. Uneven moderate blood filling of the renal glomeruli, 11% and 73% of them on the area of ​​the studied sections underwent glomerulosclerosis. Unevenly pronounced sclerosis of the glomeruli). Oxalate crystals are immured in separate sclerosed glomeruli. Diffusely in the sections are small and medium-sized foci of the "thyroid kidney" (groups of tubules in a state of pronounced atrophy: small, with filamentous epithelium, their gaps are filled with pale pink colloid-like contents). Protein granular dystrophy of the epithelium of the tubules, necrobiosis-necrosis of individual epitheliocytes and groups of cells, In the lumen of a large number of tubules, the presence of elongated oxalate crystals with rounded edges and their drusen in the form of "pits", "flower", "shells". In the lumens of the tubules there are pale pink granular masses, similar to leached erythrocytes, desquamated epitheliocytes. Single small thin-walled cysts were found, filled with homogeneous pale pink contents, with heap accumulations of small oxalate crystals. A small fragment of PCLS with polyp-like and adenomatous growth of the epithelium in the lumen was also found.

THYROID GLAND (1 object) - against the background of the predominance of weak blood supply, some small vessels are moderately plethoric. Pronounced diffuse edema of the stroma. The follicles are predominantly of medium size, their walls are lined with 1-2 layers of cubic thyrocytes, the gaps are filled with pink homogeneous or with groups of parallel linear cracking colloid. In a number of follicles there are clusters of several compacted basophilic grains. A few oxalate crystals are visible in individual follicles.

Given the combination of the presence of oxalate crystals in the lung tissue against the background of inflammation, as well as in a large number of renal tubules, kidney microcysts, sclerotic renal glomeruli, in the colloid of the thyroid gland, in this case there is dysmetabolic fermentopathy - a violation of the metabolism of oxalic acid- hyperoxaluric oxalic acid crystalluria.

The urinary part of the excretory system includes the kidneys - paired parenchymal organs. Outside, the kidney is covered with a connective tissue capsule, from which septa extend, dividing the organ into weakly expressed lobules. Anatomically, the kidney is bean-shaped. It is divided into cortex and medulla. The cortical substance is located on the side of the convex part of the kidney. It is formed by the system of convoluted tubules of nephrons and renal corpuscles, and the medulla is represented by straight tubules of nephrons and collecting ducts. Together, both of them form the parenchyma of the organ. The stroma of the kidney is represented by thin layers of loose connective tissue, in which numerous blood and lymphatic vessels and nerves pass.

Structural and functional units of the kidneys are nephrons, which are a system of blindly beginning tubules lined with a single layer of epithelial cells - nephrocytes, the height and morphological features of which are not the same in different parts of the nephrons. The length of one nephron, for example, in humans is 30-50 mm. In total, there are about 2 million of them, so their total length is up to 100 km, and the surface is about 6 m2.

There are 2 types of nephrons: cortical and pericerebral (juxtamedullary), the system of tubules of which is located either in the cortical, or predominantly in the medulla. The blind end of the nephron is represented by a capsule that covers the vascular glomerulus and together with it forms the renal corpuscle. The proximal convoluted tubule begins from the capsule, which continues in the straight and further into the descending and ascending thin sections, forming a loop that passes into the distal straight and further to the convoluted tubules. The distal convoluted tubules of the nephrons flow into the intercalated sections, which form the collecting ducts, which are the initial sections of the urinary tract.

The nephron capsule is a cup-shaped cavity formation, limited by two sheets - internal and external. The outer leaflet of the capsule consists of flat nephrocytes. The inner leaf is represented by special cells - podocytes, which have large cytoplasmic outgrowths - cytotrabeculae, and smaller processes of cytopodia extend from them. With these processes, the podocytes are adjacent to the three-layer basement membrane, which is bordered on the opposite side by the endotheliocytes of the hemocapillaries of the vascular glomerulus of the renal corpuscle. Collectively, podocytes, a three-layer basement membrane, and endotheltocytes form the renal filter (Fig. 38).

In addition, between the hemocapillaries of the vascular glomerulus there is a mesangium, which includes 3 types of mesangiocytes: 1) smooth muscle, 2) sedentary macrophages, and 3) transit macrophages (monocytes). Smooth muscle mesangiocytes synthesize the mesangium matrix. Contracting under the action of angiotensin, vasopressin and histamine, they regulate glomerular blood flow, and macrophages recognize and phagocytize antigens with the help of Fc receptors.

Rice. 38. . 1 - endotheliocyte of the hemocapillary of the renal corpuscle; 2 - three-layer basement membrane; 3 - podocyte; 4 - podocyte cytotrabecula; 5 - cytopedicles; 6 - filtration gap; 7 - filtration diaphragm; 8 - glycocalyx; 9 - cavity of the capsule of the renal corpuscle; 10 - erythrocyte.

The renal filter is involved in the 1st phase of filtering the contents of the blood plasma into the cavity of the nephron capsule. It has selective permeability: it retains negatively charged macromolecules, formed elements and plasma proteins (antibodies, fibrinogen). As a result of this selective filtration, primary urine is formed. The atrial natriuretic factor (PNUF) contributes to the increase in filtration rate.

The proximal part of the nephron is formed by low prismatic or cubic cells, a characteristic feature of which is the presence of a brush border at the apical pole and a basal labyrinth formed by invaginations of the basal part of the plasmalemma, between which mitochondria are located. Here, water, electrolytes, glucose (100%), amino acids (98%), uric acid (77%), urea (60%) are reabsorbed into the blood.

The thin section of the nephron loop is lined with flat cells, and its ascending part and the convoluted distal section are formed by the same cubic nephrocytes as in the proximal section, however, they do not have basal striation and the brush border is not expressed. In these departments, electrolytes and water are reabsorbed.

Nephrons flow into collecting ducts lined with high cylindrical epithelium, among the cells of which light and dark are distinguished. Dark cells are believed to produce hydrochloric acid, which acidifies urine, while light cells are involved in the reabsorption of water and electrolytes, as well as in the production of prostaglandins.

The circulatory system of the kidneys

From the side of the concave part (gate) of the kidney, the renal artery enters it and the ureter and renal vein exit. The renal artery, having entered the gates of the organ, gives interlobar branches, which, along the interlobar connective tissue septa (between the cerebral pyramids), reach the border between the cortical and medulla, where they form arcuate arteries. Interlobular arteries depart from the arcuate arteries towards the cortical substance, giving branches to the renal bodies of the cortical and pericerebral nephrons. These branches are called afferent arterioles. In the renal corpuscle, the afferent arteriole splits into many capillaries of the vascular glomerulus. The capillaries of the vascular glomerulus, gathering together, form the efferent arteriole, which again breaks up into a system of hemocapillaries of the peritubular network, braiding the convoluted tubules of the nephron. The hemocapillaries of the peritubular network of the cortex, gathering together, form stellate veins, which pass into the interlobular veins and then into the arcuate, and then into the interlobar veins, forming the renal vein. The efferent arterioles of the vascular glomeruli of the paracerebral nephrons break up into false straight arterioles heading to the medulla, and then to the cerebral peritubular network of capillaries, which pass into straight venules that flow into the arcuate veins. A feature of the cortical nephrons that carry out arterioles is that their diameter is smaller than in the afferent arterioles, which creates the necessary conditions for plasma filtration into the cavity of the nephron capsule, resulting in the formation of primary urine. The diameter of the afferent and efferent arterioles of the pericerebral nephrons is the same, therefore, plasma filtration does not occur in them, and functionally they participate in a kind of unloading of the renal blood flow.

Endocrine apparatus of the kidneys

The endocrine apparatus of the kidneys is involved in the regulation of general and renal blood flow and hematopoiesis.

1. renin-angitensin apparatus(juxtaglomerular apparatus - YUGA), which includes Juxtaglomerularcells , Located in the wall of afferent and efferent arterioles hard spot ("sodium receptor") - nephrocytes of that part of the distal convoluted tubule, which is adjacent to the renal corpuscle between the afferent and efferent arterioles, Juxtavascular cells , located in a triangle between the dense spot and the afferent and efferent arterioles, and Mesangiocytes (Fig. 39). Juxtaglomerular cells and, possibly, mesangiocytes of JGA secrete renin into the blood, which catalyzes the formation of angiotensins that cause a vasoconstrictive effect, and also stimulates the production of aldosterone in the adrenal cortex and vasopressin (ADH) in the anterior hypothalamus. Aldosterone enhances the reabsorption of Na + and Cl - in the distal nephrons, and vasopressin - water in the remaining parts of the nephrons and collecting ducts, resulting in increased blood pressure (BP). It is believed that juxtavascular cells produce erythropoietins.

Rice. 39. . A- afferent arterioleJ- juxtaglomerular cells;MD- hard spotL- juxtavascular cells.

2. prostaglandin apparatus - JGA antagonist: dilates blood vessels, increases renal (glomerular) blood flow, urine output and Na + excretion. The stimulus for its activation is ischemia caused by renin, resulting in an increase in the concentration of angiotensins, vasopressin, and kinins in the blood. Prostaglandins are synthesized in the medulla by the nephrocytes of the nephron loops, the clear cells of the collecting ducts, and the interstitial cells of the stroma of the kidneys.

3. Kallikrein-kinin complex has a strong vasodilating effect, increases natriuresis and diuresis due to inhibition of sodium and water reabsorption in the nephron tubules.

Kinins are low molecular weight peptides formed from precursor proteins - kininogens, which come from the blood plasma into the cytoplasm of nephrocytes of the distal tubules of nephrons, where they are converted into kinins with the participation of kallikrein enzymes. The kallikrein-kinin apparatus stimulates the production of prostaglandins. Therefore, the vasodilating effect is a consequence of the stimulating effect of kinins on the production of prostaglandins.