home Audience 5 Histology of human kidneys. Kidney structure: anatomical and histological features Nephron structure histology

Histology of human kidneys. Kidney structure: anatomical and histological features Nephron structure histology

Lecture 27: Urinary system.

General characteristics, functions of the urinary system.

Sources, the principle of the structure of 3 successive buds in the embryonic period. Age-related changes in the histological structure of the kidneys.

Histological structure, histophysiology of the nephron.

Endocrine kidney function.

Regulation of kidney function.

As a result of metabolism in cells and tissues, energy is generated, but at the same time, end products of metabolism are also formed that are harmful to the body and must be removed. These wastes from the cells enter the blood. The gaseous part of the end products of metabolism, for example CO 2, is removed through the lungs, and the products of protein metabolism through the kidneys. So, the main function of the kidneys is to remove metabolic end products from the body (excretory or excretory function). But the kidneys also perform other functions:

Participation in water-salt metabolism.

Participation in maintaining normal acid-base balance in the body.

Participation in the regulation of blood pressure (prostaglandin and renin hormones).

Participation in the regulation of erythrocytopoiesis (by the hormone erythropoietin).

II. Sources of development, the principle of the structure of 3 consecutive buds.

In the embryonic period, 3 excretory organs are sequentially formed: the pronephros, the first kidney (mesonephros) and the final kidney (metanephros).

Predpochka formed from the anterior 10 segmental legs. Segmental legs break off from the somites and turn into tubules - protonephridia; at the end of attachment to the splanchnotomes, the protonephridia freely open into the coelomic cavity (the cavity between the parietal and visceral leaves of the splanchnotomes), and the other ends connecting form the mesonephric (Wolffian) duct, which flows into the expanded area of the hindgut - the cloaca. The human adrenal duct does not function (an example of repetition of phylogeny in ontogenesis); soon the protonephridia undergo reverse development, but the mesonephric duct is preserved and participates in the formation of the first and final kidney and reproductive system.

Ikidney (mesonephros) is formed from the next 25 segmental legs located in the torso area. The segmental stalks break off from both the somites and the splanchnotomes and transform into the tubules of the first kidney (metanephridia). One end of the tubules ends in a blind vesicular extension. Branches from the aorta approach the blind end of the tubules and are pressed into it, turning the blind end of the metanephridia into a 2-walled glass - a renal corpuscle is formed. The other end of the tubules flows into the mesonephric (Wolffian) duct, which remains from the adrenal cortex. The first kidney functions and is the main excretory organ in the embryonic period. In the renal corpuscles, waste products are filtered from the blood into the tubules and enter through the Wolffian duct into the cloaca.

Subsequently, some of the tubules of the first kidney undergo reverse development, and some take part in the formation of the reproductive system (in men). The mesonephric duct is preserved and takes part in the formation of the reproductive system.

The final bud is formed in the 2nd month of embryonic development from nephrogenic tissue (the unsegmented part of the mesoderm connecting somites with splanchnatoms), mesonephric duct and mesenchyme. From nephrogenic tissue, renal tubules are formed, which, with their blind end, interacting with blood vessels, form renal corpuscles (see kidney I above); The tubules of the final kidney, in contrast to the tubules of the first kidney, are greatly elongated and successively form proximal convoluted tubules, the loop of Henle and distal convoluted tubules, i.e. The nephron epithelium is formed from nephrogenic tissue as a whole. Towards the distal convoluted tubules of the final kidney, a protrusion of the wall of the Wolffian duct grows from its lower section  the epithelium of the ureter, pelvis, renal calyces, papillary tubules and collecting ducts are formed.

In addition to nephrogenic tissue and the Wolffian duct, the formation of the urinary system involves:

The transitional epithelium of the bladder is formed from the endoderm of the allantois (the urinary sac is a protrusion of the endoderm of the posterior end of the first intestine) and ectoderm.

The epithelium of the urethra is made of ectoderm.

From the mesenchyme are the connective tissue and smooth muscle elements of the entire urinary system.

From the visceral layer of splanchnotomes is the mesothelium of the peritoneal covering of the kidneys and bladder.

Age-related features of the kidney structure:

in newborns: in the preparation there are a lot of renal corpuscles located close to each other, the renal tubules are short, the cortex is relatively thin;

in a 5-year-old child: the number of renal corpuscles in the field of view decreases (diverge from each other due to an increase in the length of the renal tubules; but there are fewer tubules and their diameter is smaller than in adults;

by the time of puberty: the histological picture does not differ from adults.

III. Histological structure of the kidneys. The kidney is covered with a connective tissue capsule. In the kidney parenchyma there are:

Cortex- located under the capsule, macroscopically dark red in color. Consists mainly of renal corpuscles, proximal and distal convoluted tubules of the nephron, i.e. from renal corpuscles, nephron tubules and connective tissue layers between them.

Brain matter- lies in the central part of the organ, macroscopically lighter, consists of: part of the nephron loops, collecting ducts, papillary tubules and connective tissue layers between them.

The structural and functional unit of the kidney is nephron. The nephron consists of the renal corpuscle (glomerular capsule and glomerulus choroid) and renal tubules (proximal convoluted and straight tubules, nephron loop, distal straight and convoluted tubules.

Glomerular capsule- in shape it is a 2-wall glass, consists of parietal (outer) and visceral (inner) layers, between them is the capsule cavity, which continues into the proximal convoluted tubules. The outer layer of the glomerular capsule has a simpler structure, consisting of a 1-layer squamous epithelium on the basal membrane. The inner layer of the glomerular capsule has a very complex configuration; on the outside it covers all the capillaries of the glomerulus located inside the capsule (each separately), and consists of podocyte cells (“cells with legs”). Podocytes have several long stalk-like processes (cytotrabeculae) with which they wrap around capillaries. Numerous small processes - cytopodia - extend from the cytotrabeculae. The inner layer does not have its own basement membrane and is located on the basement membrane of the capillaries outside.

Urine with a volume of about 100 l/day is filtered into the capsule cavity from the capillaries and then enters the proximal convoluted tubules.

Vascular glomerulus is located inside the glomerular capsule (2-walled glass) and consists of an afferent arteriole, a capillary glomerulus and an efferent arteriole. The afferent arteriole has a larger diameter than the efferent arteriole - therefore, the pressure necessary for filtration is created in the capillaries between them.

Glomerular capillaries belong to the capillaries of the fenestrated (visceral) type, the inside is lined with endothelium with fenestrae (thinned areas in the cytoplasm) and slits, the basement membrane of the capillaries is thickened (3-layer) - the inner and outer layers are less dense and light, and the middle layer is more dense and dark (consists of thin fibrils forming a network with a cell diameter of about 7 nm); due to the fact that the diameter of the afferent arteriole is larger than the efferent arteriole, the pressure in the capillaries is high (50 mm Hg or more) - ensures filtration of urine from the blood); on the outside, the capillaries are enclosed by the cytotrabeculae of the podocytes of the visceral layer of the glomerular capsule. Between the podocytes there are a small number of mesangial cells (fibrous, similar in structure to pericytes; function: phagocytose, participate in the production of the hormone renin and the main substance, are capable of contraction and regulate blood flow in the capillaries of the glomerulus).

Between the blood in the glomerular capillaries and the cavity of the glomerular capsule there is a renal filter or filtration barrier consisting of the following components:

Endothelium of glomerular capillaries.

3-layer basement membrane, common to endothelium and podocytes.

Podocytes of the inner layer of the glomerular capsule.

The kidney filter has selective permeability, allowing all blood components to pass through except blood cells and large-molecular plasma proteins (A-bodies, fibrinogen, etc.).

Kidney tubules begin with the proximal convoluted tubules, where urine flows from the cavity of the glomerular capsule, then continue: proximal straight tubules  nephron loop (Henle)  distal straight tubules  distal convoluted tubules.

Morpho-functional differences between proximal and distal convoluted tubules

Signs	Proximal convoluted tubule	Distal convoluted tubules
	About 60 microns
Epithelium	1-ply cubic edged Has microvilli C/p-ma cloudy (pinocytosis)	1-layer cubic (low-prismatic) Does not have microvilli Has basal striations C/p-ma transparent
	Reabsorption of proteins, carbohydrates, salts and water	Reabsorption of water and salts

In the basal part of the epithelial cells of the proximal and distal convoluted tubules there is striation formed by deep folds of the cytolemma and the mitochondria lying in them. A large number of mitochondria in the zone of basal striation of the tubules are necessary to provide energy for the processes of active reabsorption from urine into the blood of proteins, carbohydrates and salts in the proximal convoluted tubules, and salts in the distal convoluted tubules. The proximal and distal convoluted tubules are intertwined with a peritubular network of capillaries (branches of the efferent arterioles of the choroid glomerulus of the renal corpuscles).

Nephron loop located between the proximal and distal straight tubules, consists of a descending (lined by 1-layer squamous epithelium) and ascending limb (lined by 1-layer cuboidal epithelium).

Depending on the location and structural features, they are distinguished cortical(surface and intermediate) and pericerebral (juxtamedullary) nephrons, which differ in the following characteristics:

Signs	Cortical nephrons	Pericerebral nephrons
Location	In the cortex, only the loop of Henle descends into the medulla	At the border with the medulla, the loop of Henle goes deep into the medulla
Ratio d bring. and takeout. arterioles	The diameter of the bringing art is almost 2 times larger	The diameters of the compared arterioles are equal
Pressure in the capillaries club.	70-90 mm Hg.	40 mm Hg or less
Expressiveness of the peritubular network of capillaries
Total hydrodynamic resistance of nephron vessels
Quantity in kidneys
	Urination	Vascular shunt

Endocrine kidney function. The kidneys have a juxtaglomerular apparatus (periglomerular apparatus), which produces the hormone renin (regulates blood pressure) and is involved in the production of erythropoietin (regulates erythrocytopoiesis). YUGA consists of the following components:

Juxtaglomerular cells lie under the endothelium of the afferent arterioles; there are few of them in the efferent arterioles. The cytoplasm contains PAS-positive renin granules.

Macula densa cells are thickened epithelium of the portion of the wall of the distal convoluted tubules lying between the afferent and efferent arterioles. They have receptors for detecting the concentration of Na+ in urine.

Juxtavascular cells (Gurmagtig cells) are polygonal cells lying in the triangular space between the macula densa and the afferent and efferent arterioles.

Mesangial cells (located on the outer surface of the glomerular capillaries among the podocytes, see above the structure of the renal corpuscles).

JGA produces the hormone renin; under the influence of renin, the blood plasma globulin angiotensinogen is converted first into angiotensin I, then into angiotensin II. Angiotensin II, on the one hand, has a direct vasoconstrictor effect and an increase in blood pressure, on the other hand, it increases the synthesis of aldosterone in the zona glomerulosa of the adrenal glands; the reabsorption of Na+ and water in the kidneys increases; the volume of tissue fluid in the body increases; the volume of circulating blood increases; increased blood pressure.

Epithelial cells of the loops of Henle and collecting ducts produce prostaglandins, which have a vasodilating effect and increase glomerular blood flow, resulting in an increase in the volume of urine excreted.

It is synthesized in the epithelial cells of the distal tubules of the nephron. kallekrein, under the influence of which plasma protein kininogen goes into active form kinins. Kinins have a strong vasodilating effect, reduce the reabsorption of Na+ and water  increases urination.

Regulation of kidney function:

Kidney function depends on blood pressure, i.e. from vascular tone regulated by sympathetic and parasympathetic nerve fibers.

Endocrine regulation:

a) aldosterone of the zona glomerulosa of the adrenal glands  enhances the active reabsorption of salts to a greater extent in the distal, to a lesser extent in the proximal convoluted tubules of the kidneys;

b) antidiuretic hormone (vasopressin) of the supraoptic and paraventricular nuclei of the anterior part of the hypothalamus  increasing the permeability of the walls of the distal convoluted tubules and collecting ducts, enhances the passive reabsorption of water.

The urinary department of the excretory system includes the kidneys - paired parenchymal organs. The outside of the kidney is covered with a connective tissue capsule, from which septa extend, dividing the organ into weakly defined lobules. Anatomically, the kidney has a bean-shaped shape. It distinguishes between the cortex and medulla. The cortex is located on the side of the convex part of the kidney. It is formed by a system of convoluted nephron tubules and renal corpuscles, and the medulla is represented by straight nephron tubules and collecting ducts. Together, both 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.

The structural and functional units of the kidneys are nephrons, which are a system of blindly starting tubes 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 their 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 cortex 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 then convoluted tubules. The distal convoluted tubules of the nephrons flow into the intercalary sections, which form the collecting ducts, which are the initial sections of the urinary tract.

The nephron capsule is a cup-shaped cavity formation bounded by two layers - inner and outer. The outer layer of the capsule consists of flat nephrocytes. The inner leaf is represented by special cells - podocytes, which have large cytoplasmic processes - 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 endothelial cells of the hemocapillaries of the vascular glomerulus of the renal corpuscle. Together, 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 contains 3 types of mesangiocytes: 1) smooth muscle, 2) resident macrophages and 3) transit macrophages (monocytes). Smooth muscle mesangiocytes synthesize the mesangium matrix. Contracting under the influence of angiotensin, vasopressin and histamine, they regulate glomerular blood flow, and macrophages, using Fc receptors, recognize and phagocytose antigens.

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

The kidney filter is involved in the 1st phase of filtration of blood plasma contents 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. Atrial natriuretic factor (ANF) contributes to an 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%), and 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, but they do not have basal striations and the brush border is not pronounced. In these sections, reabsorption of electrolytes and water occurs.

Nephrons flow into collecting ducts lined with tall columnar epithelium, the cells of which are distinguished between light and dark. The dark cells are thought to produce hydrochloric acid, which acidifies the urine, while the light cells are believed to be involved in the reabsorption of water and electrolytes, as well as the production of prostaglandins.

Blood supply to the kidneys

From the side of the concave part (hila) of the kidney, the renal artery enters it and the ureter and renal vein exit. The renal artery, entering the portal of the organ, gives off interlobar branches, which along the interlobar connective tissue septa (between the medullary pyramids) reach the border between the cortex and medulla, where they form the arcuate arteries. Interlobular arteries extend from the arcuate arteries towards the cortex, giving off branches to the renal corpuscles 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, coming together, form the efferent arteriole, which again breaks up into the hemocapillary system of the peritubular network, entwining the convoluted tubules of the nephron. The hemocapillaries of the peritubular network of the cortex, coming together, form stellate veins, which pass into the interlobular veins and then into the arcuate veins, and then into the interlobar veins, forming the renal vein. The efferent arterioles of the vascular glomeruli of the pericerebral nephrons break up into false straight arterioles that go into the medulla, and then into the cerebral peritubular network of capillaries, which turn into straight venules that flow into the arcuate veins. A feature of the efferent arterioles of the cortical nephrons is that their diameter is smaller than that of the afferent arterioles, which creates the necessary conditions for the filtration of plasma into the cavity of the nephron capsule, resulting in the formation of primary urine. The diameter of the afferent and efferent arterioles of the peri-cerebral nephrons is the same, so 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 takes part in the regulation of general and renal blood flow and hematopoiesis.

1. Renin-angitensin apparatus(juxtaglomerular apparatus - JGA), which includes Juxtaglomerularcells , Located in the wall of the afferent and efferent arterioles, Dense spot (“sodium receptor”) – nephrocytes of that part of the distal convoluted tubule that is adjacent to the renal corpuscle between the afferent and efferent arterioles, Juxtavascular cells , located in the triangle between the macula densa and the afferent and efferent arterioles, and Mesangiocytes (Fig. 39). Juxtaglomerular cells and, possibly, mesangiocytes of the JGA secrete renin into the blood, which catalyzes the formation of angiotensins, causing a vasoconstrictor effect, and also stimulates the production of aldosterone in the adrenal cortex and vasopressin (ADH) in the anterior hypothalamus. Aldosterone increases the reabsorption of Na+ and Cl - in the distal parts of the nephrons, and vasopressin increases the reabsorption of water in the remaining parts of the nephrons and collecting ducts, resulting in an increase in blood pressure (BP). It is believed that juxtavascular cells produce erythropoietin.

Rice. 39. . A– afferent arteriole;J- juxtaglomerular cells;M.D.- dense stain;L– juxtavascular cells.

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

3. Kallikrein-kinin complex has a strong vasodilatory effect, increases natriuresis and diuresis due to inhibition of the reabsorption of sodium and water 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 the nephrons, where they are converted into kinins with the participation of kallikrein enzymes. The kallikrein-kinin apparatus stimulates the production of prostaglandins. Therefore, the vasodilatory effect is a consequence of the stimulating effect of kinins on the production of prostaglandins.

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

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

At the beginning, the preference is formed. 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 kidney exists for up to 2 days, does not function, dissolves, but the mesonephric duct remains.

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

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

Bud

The outside is covered with a thin connective tissue capsule. The kidney contains a cortical substance, 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 apex 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. Some of the straight tubules in the cortex are located in groups, and such formations are called medullary rays.

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

The proximal and distal tubules are built from convoluted tubules.

Nephron structure

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 capillaries, which form a vascular glomerulus; the blood capillaries merge, forming an efferent arteriole, which leaves the renal corpuscle.

The glomerular capsule contains an outer and an inner leaf. Between them there is a capsule cavity. The inside of the cavity is lined with epithelial cells - podocytes: large branched cells, which with processes are attached to the basement membrane. The inner leaf penetrates the vascular glomerulus and envelops all blood capillaries from the outside. In this case, its basement membrane merges with the basement membrane of the blood capillaries to form one basement membrane.

The inner layer and the wall of the blood capillary form a renal barrier (the composition of this barrier includes: a basement membrane, it contains 3 layers, its middle layer contains a fine network of fibrils and podocytes. The barrier into the hole allows all the formed elements to pass through: 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 marginal epithelium, with well-developed organelles.

Then comes a new loop of nephron. The distal convoluted tubule is lined with cubic 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.

Collecting ducts are straight tubules lined with cubic and columnar epithelium, in which light and dark epithelial cells are distinguished. The collecting ducts merge to form papillary canals, two of which open at the top of the medullary pyramids.

Histology is one of the most effective examinations today, which helps to promptly identify all dangerous cells and malignant neoplasms. With the help of histological examination, all tissues and internal organs of a person can be studied in detail. The main advantage of this method is that with its help you can get the most accurate result. In order to study, histology is also one of the most effective examinations.

What is histology?

Today, modern medicine offers a wide range of different examinations with which a diagnosis can be made. But the problem is that many types of studies have their own percentage of error in determining an accurate diagnosis. And in this case, histology comes to the rescue as the most accurate research method.

Histology is the study of human tissue material under a microscope. Thanks to this method, a specialist identifies all pathogenic cells or neoplasms that are present in a person. It is worth noting that this method of studying is the most effective and accurate at the moment. Histology is one of the most effective diagnostic methods.

Methodology for collecting material for histology

As described above, histology is the study of a sample of human material under a microscope.

To study tissue material using a histological method, the following manipulations are performed.

When a kidney is examined (histology), the drug must be indicated under a specific number.

The material being tested is immersed in a liquid, which increases the density of the sample. The next stage is pouring paraffin into the sample under study and cooling it until it becomes solid. In this form, it is much easier for a specialist to make a thin section of the sample for detailed examination. Then, when the process of cutting thin plates is completed, all the resulting samples are painted with a certain pigment. And in this form the tissue is sent for detailed study under a microscope. During the examination, the following is indicated on a special form: “kidney, histology, specimen No...” (a specific number is assigned).

In general, the process of preparing a sample for histology requires not only increased attention, but also high professionalism from all laboratory specialists. It is worth noting that conducting such a study requires a week of time.

In some cases, when the situation is urgent and urgent histology is required, laboratory assistants may resort to a rapid test. In this case, the collected material is pre-frozen before cutting the sample. The disadvantage of such manipulation is that the results obtained will be less accurate. The rapid test is only suitable for detecting tumor cells. At the same time, the number and stages of the disease must be studied separately.

Methods for collecting analysis for histology

If the blood supply to the kidney is impaired, histology is also the most effective research method. There are several ways to carry out this manipulation. In this case, everything depends on the preliminary diagnosis that was made to the person. It is important to understand that tissue collection for histology is a very important procedure that helps to obtain the most accurate answer.

How is a kidney cut (histology)?

The needle is inserted through the skin under strict control of instruments. Open method - kidney material is removed during surgery. For example, during the removal of a tumor or when a person has only one kidney working. Urethroscopy - this method is used for children or pregnant women. Collecting material using urethroscopy is indicated in cases where there are stones in the renal pelvis.

The trans jugular technique is used in cases where a person suffers from bleeding disorders, is overweight, has respiratory failure, or has congenital kidney defects (kidney cysts). Histology is performed in various ways. Each case is considered by a specialist individually, according to the characteristics of the human body. Only a qualified doctor can provide more detailed information about such manipulation. It is worth noting that you should only contact experienced doctors; do not forget the fact that this manipulation is quite dangerous. A doctor without experience can do a lot of harm.

How is the procedure for collecting material for kidney histology performed?

A procedure such as kidney histology is carried out by a specialist in a specific office or in the operating room. In general, this manipulation takes about half an hour under local anesthesia. But in some cases, if there is a doctor’s testimony, general anesthesia is not used; it can be replaced by sedatives, under which the patient can follow all the doctor’s instructions.

What exactly are they doing?

Kidney histology is carried out as follows. The person is placed face down on a hospital bed, and a special pad is placed under the stomach. If a kidney has previously been transplanted from a patient, the person should lie on his back. When performing histology, the specialist monitors the patient’s pulse and blood pressure throughout the procedure. The doctor performing this procedure treats the area where the needle is planned to be inserted, then administers anesthesia. It is worth noting that in general, when performing such manipulation, painful sensations are minimized. As a rule, the manifestation of pain largely depends on the general condition of the person, as well as on how correctly and professionally the kidney histology was performed. Since almost all possible risks of complications are associated only with the professionalism of the doctor.

A small incision is made in the area where the kidneys are located, then the specialist inserts a thin needle into the resulting hole. It is worth noting that this procedure is safe, since the entire process is controlled using ultrasound. When inserting the needle, the doctor asks the patient to hold his breath for 40 seconds if the patient is not under local anesthesia.

When the needle penetrates the skin to the kidney, a person may feel a feeling of pressure. And when a tissue sample is taken directly, a person may hear a small click. The thing is that this procedure is performed using the spring method, so these sensations should not frighten a person.

It is worth noting that in some cases I can inject a certain substance into the patient’s vein, which will show all the most important blood vessels and the kidney itself.

Kidney histology in rare cases can be carried out in two or even three punctures if the collected sample is not enough. Well, when the tissue material is taken in the required quantity, the doctor removes the needle, and a bandage is applied to the place where the manipulation was performed.

In what cases can kidney histology be prescribed?

To study the structure of the human kidney, histology is the best choice. Relatively few people think about the fact that histology is much more accurate than other diagnostic methods. But there are several cases when kidney histology is a mandatory procedure that can save a person’s life, namely:

If acute or chronic defects of unknown origin are identified;

For complex infectious diseases of the urinary tract;

If blood is detected in the urine;

With high uric acid;

To clarify the defective state of the kidneys;

If the kidney that was previously transplanted is unstable;

To determine the severity of a disease or injury;

If there is a suspicion of a cyst in the kidney;

If a malignant neoplasm is suspected, histology is mandatory.

It is important to understand that histology is the most reliable way to identify all kidney pathologies. Using tissue samples, an accurate diagnosis can be made and the severity of the disease can be determined. Thanks to this method, a specialist will be able to select the most effective treatment and prevent all possible complications. This is especially true in cases where the primary results indicate that tumors have appeared in a given organ.

What complications may arise when taking material for research?

What do you need to know if you are undergoing histology of a kidney tumor? First of all, each person should take into account that in some cases complications may develop. The biggest risk is damage to the kidney or other organ. However, there are still some risks, namely:

Possible bleeding. In this case, an urgent blood transfusion is necessary. In rare cases, surgery will be required to further remove the damaged organ.

Possible rupture of the lower pole of the kidney.

In some cases, purulent inflammation of the fatty membrane around the organ itself.

Bleeding from the muscle.

If air enters, pneumothorax may develop.

Infectious infection.

It is worth noting that these complications occur extremely rarely. As a rule, the only negative symptom is a slight increase in temperature after the biopsy. In any case, if there is a need for such a procedure, it is better to contact a qualified specialist who has enough experience in carrying out such manipulation.

How is the postoperative period going?

People who are about to undergo this manipulation should know a few simple rules for the postoperative period. You should follow your doctor's recommendations exactly.

What should a patient know and do after a histology procedure?

After this manipulation, it is not recommended to get out of bed for six hours. The specialist performing this procedure must monitor the patient’s pulse and blood pressure. In addition, it is necessary to check the person’s urine to see if there is blood in it. During the postoperative period, the patient should drink plenty of fluids. For two days after this manipulation, the patient is strictly prohibited from performing any physical exercise. Moreover, physical activity should be avoided for 2 weeks. As the anesthesia wears off, the person undergoing the procedure will experience pain, which can be relieved with a mild pain reliever. Typically, if a person has not had any complications, they may be allowed to go home the same day or the next day.

It is worth noting that a small amount of blood in the urine may be present for 24 hours after the biopsy is taken. There is nothing wrong with this, so blood impurities should not frighten a person. It is important to understand that there is no alternative to renal histology. Any other diagnostic method does not provide such accurate and detailed data.

In what cases is it not recommended to collect material for histological examination?

There are several contraindications for collecting material for research, namely:

If a person has only one kidney;

If there is a blood clotting disorder;

If a person is allergic to novocaine;

If a tumor was found in the kidney;

With thrombosis of the renal veins;

In case of renal failure.

If a person suffers from at least one of the above ailments, then taking material from the kidneys is strictly prohibited. Since this method has certain risks of developing serious complications.

Conclusion

Modern medicine does not stand still; it is constantly developing and giving people new discoveries that help save human life. Such discoveries include histological examination; it is the most effective today for identifying many diseases, including cancerous tumors.

The human body is a reasonable and fairly balanced mechanism.

Among all infectious diseases known to science, infectious mononucleosis has a special place...

The world has known about the disease, which official medicine calls “angina pectoris,” for quite a long time.

Mumps (scientific name: mumps) is an infectious disease...

Hepatic colic is a typical manifestation of cholelithiasis.

Brain edema is a consequence of excessive stress on the body.

There are no people in the world who have never had ARVI (acute respiratory viral diseases)...

A healthy human body is able to absorb so many salts obtained from water and food...

Knee bursitis is a widespread disease among athletes...

Histology kidney preparation

Kidney histology

The kidney is covered with a capsule that has two layers and consists of collagen fibers with a slight admixture of elastic fibers, and a layer of smooth muscles in depth. The latter directly pass into the muscle cells of the stellate veins. The capsule is penetrated by blood and lymphatic vessels, closely connected with the vascular system of not only the kidney, but also the perinephric tissue. The structural unit of the kidney is the nephron, which includes the glomerulus together with the Shumlyansky-Bowman capsule (together constituting the renal corpuscle), convoluted tubules of the first order, loop of Henle, convoluted tubules of the second order, straight tubules and collecting ducts that open into the calyces of the kidney (color table). ., Fig. 1 - 5). The total number of nephrons is up to 1 million.

Rice. 1. Frontal section of the kidney (diagram): 1 - capsule; 2-cortical substance; 3 - medulla (Malpighi pyramids); 4 - renal pelvis. Fig. 2. Section through the kidney lobe (low magnification): 1 - capsule; 2 - cortex; 3 - transversely cut convoluted urinary tubules; 4 - longitudinally cut straight urinary tubules; 5 - glomeruli.

Rice. 3. Section through a section of the cortex (high magnification): 1 - glomerulus; 2 - outer wall of the glomerular capsule; 3 - main section of the urinary tubule; 4 - intercalary section of the urinary tubule; 5 - brush border. Fig. 4. Section through the superficial part of the medulla (high magnification): 1 - thick section of the loop of Henle (ascending limb); 2 - thin section of the loop of Henle (descending limb).

Rice. 5. Incision through the deep part of the medulla (high magnification). Collecting tubes.

The glomerulus is formed by blood capillaries into which the afferent arteriole breaks up. Collecting into a single outflow tract, the capillaries of the glomerulus give rise to the efferent arteriole (vas efferens), the caliber of which is much narrower than the efferent arteriole (vas afferens). The exception is the glomeruli located on the border between the cortical and medulla layers, in the so-called juxtamedullary zone. Juxtamedullary glomeruli are larger in size, and the caliber of their afferent and efferent vessels is the same. Due to their location, the juxtamedullary glomeruli have a special circulation that is different from that of the cortical glomeruli (see above). The basement membrane of the glomerular capillaries is dense, homogeneous, up to 400 Å thick, and contains PAS-positive mucopolysaccharides. Endothelial cells are often vacuolated. Electron microscopy reveals round holes in the endothelium up to 1000 Å in diameter, in which blood is in direct contact with the basement membrane. The capillary loops seem to be suspended on a kind of mesentery - the mesangium, which is a complex of hyaline plates made of proteins and mucopolysaccharides, between which there are cells with small nuclei and scanty cytoplasm. The glomerulus of capillaries is covered with flat cells up to 20-30 microns in size with light cytoplasm, which are in close contact with each other and make up the inner layer of the Shumlyansky-Bowman capsule. This layer is connected to the capillaries by a system of channels and lacunae in which provisional urine filtered from the capillaries circulates. The outer layer of the Shumlyansky-Bowman capsule is represented by flat epithelial cells, which at the point of transition to the main section become taller and cubic. In the area of the vascular pole of the glomerulus there are a special kind of cells that form the so-called endocrine apparatus of the kidney - the juxtaglomerular apparatus. One of these cells - granular epithelioid - are located in 2-3 rows, forming a sleeve around the afferent arteriole just before its entrance into the glomerulus. The number of granules in the cytoplasm varies depending on the functional state. Cells of the second type - small, flat, elongated, with a dark nucleus - are placed in the angle formed by the afferent and efferent arterioles. These two groups of cells, according to modern views, arise from smooth muscle elements. The third variety is a small group of tall, elongated cells with nuclei located at different levels, as if piled on top of each other. These cells belong to the place of transition of the loop of Henle into the distal convoluted tubule and, based on the dark spot formed by piled-up nuclei, are designated as macula densa. The functional significance of the juxtaglomerular apparatus is reduced to the production of renin.

The walls of convoluted tubules of the first order are represented by cubic epithelium, at the base of which the cytoplasm has radial striations. Parallel rectilinear, highly developed folds of the basement membrane form a kind of chamber containing mitochondria. The brush border in the epithelial cells of the proximal nephron is formed by parallel protoplasmic filaments. Its functional significance has not been studied.

The loop of Henle has two limbs - a descending thin one and an ascending thick one. They are lined with flat epithelial cells, light, well-receptive to aniline dyes, with a very weak granularity of the cytoplasm, which sends few and short microvilli into the lumen of the tubule. The border of the descending and ascending limbs of the loop of Henle corresponds to the location of the macula densa of the juxtaglomerular apparatus and divides the nephron into proximal and distal sections.

The distal part of the nephron includes convoluted tubules of the second order, practically indistinguishable from the convoluted tubules of the first order, but lacking a brush border. Through a narrow section of straight tubules they pass into collecting ducts, lined with cuboidal epithelium with light cytoplasm and large light nuclei. The collecting ducts open through 12-15 passages into the cavity of the small calyces. In these areas, their epithelium becomes high cylindrical and passes into the double-row epithelium of the calyces, and the latter into the transitional epithelium of the urinary pelvis. The proximal part of the nephron is responsible for the main reabsorption of glucose and other substances that have a high absorption threshold, while the distal part is responsible for the absorption of the main amount of water and salts.

The muscular layer of the calyces and pelvis is closely connected with the muscles of the inner layer of the kidney capsule. The fornices of the kidneys (fornices) are devoid of muscle fibers, are represented mainly by the mucous and submucosal layers and therefore are the most vulnerable place of the upper urinary tract. Even with a slight increase in intrapelvic pressure, ruptures of the renal vaults with a breakthrough of the contents of the pelvis into the substance of the kidney can be observed - the so-called pyolerenal reflux (see).

The intervening connective tissue in the cortex is extremely scarce and consists of thin reticular fibers. In the medulla it is more developed and also includes collagen fibers. There are few cellular elements in the stroma. The stroma is densely permeated with blood and lymphatic vessels. The renal arteries have a microscopically clear division into three membranes. The intima is formed by endothelium, the ultrastructure of which is almost similar to that in the glomeruli, and so-called subendothelial cells with fibrillar cytoplasm. Elastic fibers form a powerful internal elastic membrane - two or three layers. The outer shell (wide) is represented by collagen fibers with an admixture of individual muscle fibers, which, without sharp boundaries, pass into the surrounding connective tissue and muscle bundles of the kidney. In the adventitia of the arterial vessels there are lymphatic vessels, of which the large ones also contain oblique muscle bundles in their wall. In the veins, three membranes are conventional, their adventitia is almost not expressed.

The direct connection between arteries and veins is represented in the kidneys by two types of arteriovenous anastomoses: direct connection of arteries and veins during the juxtamedullary circulation and arteriovenous anastomoses such as closing arteries. All renal vessels - blood and lymphatic - are accompanied by nerve plexuses, which form along their course a thin branched network, ending in the basement membrane of the renal tubules. A particularly dense nerve network entwines the cells of the juxtaglomerular apparatus.

www.medical-enc.ru

Topic 28. Urinary system (continued)

28.2.3.5. Cortical tubules: preparations and micrographs

I. Regular (thin) cut

II. Semi-thin slice

III. Electron microphotography (ultrathin section)

28.2.3.6. Tubules of the medulla: preparations and micrographs

I. Sections of the loop of Henle

II. Sections of the loop of Henle and collecting ducts

III. Thin tubules in electron micrograph

IV. Thin tubules and collecting duct in electron micrograph

28.2.4. Participation of the kidneys in endocrine regulation

28.2.4.1. general description

II. Hormonal influences on the kidneys

III. Renin production by the kidneys (clause 22.1.2.3.II)

Place of generation	The kidneys produce renin using the so-called. juxtaglomerular apparatus (JGA) (see below).
Action of renin	a) Renin is a protein with enzymatic activity. b) In the blood, it acts on an inactive peptide (produced by the liver) - angiotensinogen, which in two stages is converted into its active form - angiotensin II.
The action of angio- tensin II	a) This product, firstly, it increases the tone of myocytes of small vessels and thereby increases blood pressure, and secondly, it stimulates the release of aldosterone in the adrenal cortex. b) The latter, as we saw from the above chain, can enhance the production of ADH.
Final action	a) Thus, excess renin production leads to not only to spasm of small vessels, but also to increased reabsorbing function of the kidneys themselves. b) The resulting increase in plasma volume also (along with vasospasm) increases blood pressure.

IV. Renal production of prostaglandins

Chemical

a) The kidneys can produce (from polyunsaturated fatty acids) the hormones prostaglandins - fatty acids containing a five-carbon cycle in their structure.

b) The group of these substances is very diverse - as are the effects they cause.

Action

The fraction of prostaglandins that is formed in the kidneys has an effect opposite to renin:

dilates blood vessels and thereby reduces pressure.

Production regulation

a) Kininogen proteins circulate in the blood plasma,

and in the cells of the distal tubules of the kidneys there are kallikrein enzymes, which cleave off active kinin peptides from kininogens.

b) The latter stimulate the secretion of prostaglandins.

28.2.4.2. Juxtaglomerular (periglomerular) apparatus

As already mentioned, JGA is responsible for the synthesis of renin.

I. Components of YUGA

Scheme - the structure of the renal corpuscle.

Full size

II. Characteristics of YUGA components

	Morphology	Function
I. Dense spot	The boundaries between cells are almost invisible, but there is an accumulation of nuclei (which is why the spot is called dense), the cells do not have basal striations.	The macula densa is believed to be an osmoreceptor: irritated by increasing Na+ concentration in primary urine and stimulates renin-producing cells.
II. Juxta-glomera- polar cells	Large cells with large granules. The contents of the granules are the hormone renin.	Renin secretion is probably stimulated by two factors: irritation of the osmoreceptor (solar macula), irritation of baroreceptors in the wall of the afferent and efferent arterioles.
III. Juxta-vascular	The cells have long processes.	It is believed that these cells are involved in the production of renin (under the influence of the same two factors) In case of insufficiency of juxtaglomerular cell function.

It follows that JGA is a receptor-endocrine formation.

III. Scheme of functioning of YUGA

The above can be summarized by the following diagram.

Electron micrograph - juxtaglomerular apparatus.

1. And here in front of us is the lower part of the photograph given in paragraph 28.2.3.2.III.

2. The following structures are visible:

afferent (1) and efferent (2) arterioles;

dense spot - part of the wall of the distal convoluted tubule adjacent to the renal corpuscle (dark area at the very bottom of the image);

juxtaglomerular cells (12) - an additional layer of dark cells under the endothelium of the afferent arteriole (similar cells, as we know, are contained in the efferent arteriole, but are practically invisible in the picture), and finally,

juxtavascular cells (11) - a collection of clear cells in the triangular space between two arterioles and the distal convoluted tubule.

28.2.4.3. Prostaglandin apparatus

28.2.5. Kidney development

28.2.5.1. Scheme

The development of the kidneys, as always, will be shown in a diagram. –

28.2.5.2. Description of the scheme

The diagram shows that in the embryonic period three pairs of urinary organs appear successively.
Preferences	In fact, they do not function and are quickly reduced.
Primary buds	a) They function during the first half of intrauterine development. b) Moreover, the mesonephric ducts, playing the role of the ureter, open into the hindgut, forming a cloaca. c) The primary buds then participate in the development of the gonads.
Final buds	a) They function from the second half of the embryonic period. b) The ureters, developing from the mesonephric ducts (along with the collecting ducts, calyces and pelvis), now open into the bladder.
Let us also pay attention to the fact that the epithelium of the renal tubules develops from the mesoderm (coelonephrodermal type of epithelium; section 7.1.1).

28.3. Urinary tract

28.3.1. general characteristics

28.3.1.1. Intra- and extrarenal pathways

28.3.1.2. Wall structure

	Calyxes and pelvis	Ureters	Bladder
1. Mucosa	a) Transitional epithelium (1.A) (clause 7.2.3.1). A. Includes 3 layers of cells: basal, intermediate and superficial; Moreover, the shape of the surface cells changes when the walls are stretched - from dome-shaped to flat. b) The lamina propria (1.B) of the mucous membrane is loose fibrous connective tissue.
	The mucous membrane of the ureters forms deep longitudinal folds.	The mucous membrane of an empty bladder forms many folds - except for the triangular area at the confluence of the ureters.
2. Submucosa	As in the lamina propria of the mucous membrane loose fibrous connective tissue (it is the presence of the submucosa that makes it possible for the mucous membrane to form folds, although this base itself is not included in the folds).
	In the lower half of the ureters, small alveolar-tubular glands are found in the submucosa (2.A).	In the area of the above triangle, there is no submucous base in the bladder (which is why folds do not form here)
3. Muscular shell	a) The muscular layer is formed by bundles of smooth myocytes (separated by connective tissue layers) and contains 2 or 3 layers. b) Cells in the layers are arranged in a spiral with the opposite (in adjacent layers) spiral direction.
In the urinary tract to the middle of the ureters - 2 layers: internal (3.A) and external (3.B).	From the middle of the ureters and in the bladder - 3 layers: internal (3.A), middle (3.B), external (3.C).
4. Outdoor shell	1. Almost everywhere the outer shell is adventitial, that is, formed by connective tissue. 2. Only part of the bladder (on top and a little on the sides) is covered by peritoneum.
c) In the walls of the urinary tract, as usual, there are also blood and lymphatic vessels, nerve endings (sensitive and efferent - parasympathetic and sympathetic), intramural ganglia and individual neurons.

28.3.1.3. Cystoid principle of urinary tract functioning

Cystoids (segments) of the urinary tract

1. a) Throughout each ureter (3), incl. at its beginning and end, there are several constrictions (5).

b) In these places in the wall of the ureter (in the submucosa and muscular layer) there are

cavernous formations, KO (4),

those. system of cavernous (cavernous) vessels.

c) In the normal state, KOs are filled with blood and close the lumen of the ureter.

d) As a result, the latter is divided into several segments (6), or cystoids.

Scheme - ureteropelvic segments.

2. The pelvis (2) and the calyces of the kidney (1) (taken together) can also be considered one such cystoid with a narrowing at its outlet.

Movement of urine

a) The movement of urine through the urinary tract does not occur continuously, but by sequentially filling the next segment.

b) A. Overflow of the segment leads, in a reflex way, to the collapse of the CP (cavernous-like formations) at the exit from the segment.

B. After this, the smooth muscle elements of the segment contract and expel urine into the next segment.

c) This principle of functioning of the urinary tract prevents the reverse (retrograde) flow of urine.

d) Removal of part of the ureter, practiced in some diseases, disrupts the coordination of its segments and causes urinary disorders.

28.3.2. Drugs

28.3.2.1. Ureter

I. Low magnification

II. High magnification

28.3.2.2. Bladder

I. Low magnification

II. High magnification

III. Intramural ganglion

nsau.edu.ru

5) Histological structure of the kidney.

The internal structure of the kidney is represented by the renal sinus, in which the renal cups, the upper part of the pelvis and the kidney's own substance, the parenchyma, consisting of the medulla and cortex, are located.

The medulla, medulla renis, is located in the central part and is represented by pyramids (17-20), pyramides renales, the base of which is directed towards the surface, and the apex - the renal papilla, papilla renalis - into the renal sinus. The apices of several pyramids are sometimes combined into a common papilla. From the bases of the pyramids, strips of medulla extend deep into the cortex and form the radiate part, pars radiata.

The cortex, cortex renis, occupies the peripheral sections and protrudes between the pyramids of the medulla, forming renal columns, columnae renales. The areas of the cortex between the rays are called the convoluted part, pars convoluta. The cortex contains most of the structural and functional units of the kidney - nephrons. Their total number reaches 1 million.

The pyramid with adjacent sections of the renal columns represents the renal lobe, lobus renis, while the radiate part, surrounded by the folded part, is the cortical lobule, lobulus corticalis.

The structural and functional unit of the kidney is the nephron. There are more than one million of them in each kidney. The nephron is a capillary glomerulus, glomerulus, surrounded by a double-walled glass-shaped capsule, capsula glomeruli. This structure is called the renal (or Malpighian) corpuscle, corpusculum renis. The renal corpuscles of the majority (up to 80%) of nephrons are located in the pars convoluta.

The nephron capsule then continues into the proximal convoluted tubule, tubulus renalis contortus proximalis, which straightens, descends into the pyramid and forms the nephron loop, ansa nephroni (loop of Henle). Returning to the cortex, the tubule twists again, tubulus contortus distalis, and through the intercalary section flows into the collecting duct, tubulus colligens, which is the beginning of the urinary tract.

Blood supply to the kidney and the process of urine formation.

Primary urine is formed as a result of filtration of protein-free blood plasma from the capillary glomerulus into the cavity of the nephron capsule.

Let's consider the diagram of the blood supply to the kidney. The renal artery entering the portal departs from the abdominal aorta, which provides it with high blood pressure necessary for filtration. It gives rise to five segmental branches. Segmental arteries give off interlobar arteries, aa. interlobares, which run in the renal columns to the base of the pyramids, where they divide into arcuate arteries, aa. arcuatae From them interlobular arteries, aa, extend into the cortex. interlobulares, which give rise to afferent vessels. The afferent vessel, vas afferens, breaks up into a network of capillaries that form a capillary glomerulus. The capillaries, merging again, form an efferent vessel, vas efferens, which is twice as thin in diameter as the afferent one. The difference in the diameter of the afferent and efferent vessels creates the blood pressure necessary for filtration in the capillaries of the glomerulus and ensures the formation of primary urine.

The efferent vessels then again disintegrate into capillary networks that intertwine the nephron tubules, from which water, salts, glucose and other substances needed by the body are reabsorbed; that is, the process of formation of secondary urine occurs. . To excrete 1.5-2 liters of secondary urine every day, 1500 liters of blood pass through the kidney vessels. The blood is then directed into the venous channel.

Thus, a feature of the circulatory system of the kidney is the presence of a double capillary network: a glomerular one for blood filtration, and a second, tubular one for reabsorption - the result of the division of the efferent arteriole, which passes into the venous bed.

Urinary structures of the kidney.

The collecting ducts descend along the medullary rays into the pyramid, where they unite into the papillary ducts, ductuli pappilares. The openings of these papillae, foramina papillaria, form ethmoidal fields, area cribrosa, at the tops of the papillae. From the papillary ducts, urine enters the small cups, calyces minores, which, 7-10 in number, cover the renal papillae. Coming together, the small cups form 2-3 large cups, calyces majores, which open into. renal pelvis, pelvis renalis, which has three forms of formation: embryonic, fetal and mature. All these formations make up the urinary tract.

Fornical apparatus.

The proximal part of the cup surrounding the papilla of the pyramid is called the fornix, fornix. Its wall contains muscle fibers that provide systole (emptying) and diastole (filling the cup).

Muscles of the fornical apparatus:

– cups that expand the cavity: m.levator fornicis, m. logitudinalis calyci;

– cups narrowing the cavity: m. sphincter fornicis and m. spiralis calyci.

6) Age characteristics. In newborns, the kidney is round and lumpy. Weight reaches 12 g. Kidney growth occurs mainly in the first year of life. By the age of 16, the growth of the cortical substance ends. At the age of over 50 years and with exhaustion, the kidneys droop. During all periods of life, the right kidney is lower.

Rice. 1.42. The structure of the nephron.

1 – glomerulus, glomerulus; 2 – proximal tubule, 2a – capsula glomeruli; 2b – tubulus renalis contortus proximalis; 3 – distal tubule, tubulus renalis contortus distalis; 4 – thin section of the loop of Henle, ansa nephroni (Henle).

7) Anomalies are associated with the position of the kidneys and their number. Quantity anomalies include: kidney aplasia, i.e. absence of a kidney (one- and two-sided); additional (third) kidney, double kidney, fused kidney (horseshoe-shaped, L-shaped, S-shaped). Positional anomalies are called kidney dystopia. Depending on the location of the kidney, there are pelvic, lumbar, ileal, and thoracic kidneys. There are anomalies of the excretory ducts and segmentation of the kidneys. Structural abnormalities include polycystic kidney disease. Potter face (syndrome) – characteristic of bilateral underdevelopment of the kidneys and other renal anomalies: widely spaced eyes (ocular hypertelorism), low position of the ears, thickened nose. Megacalycosis is enlarged renal calyces.

8) Diagnostics. When X-raying the lumbar region, you can see the contours of the lower part of the kidneys. In order to see the entire kidney, air must be injected into the perinephric tissue. X-rays make it possible to examine the excretory tree of the kidney in a living person: calyces, pelvis, ureter. To do this, a contrast agent is injected into the blood, which is released through the kidneys and, joining the urine, gives a silhouette of the renal pelvis and ureter on the radiograph. This method is called intravenous urography.

studfiles.net

Histology of human kidneys

Histology is one of the most effective examinations today, which helps to promptly identify all dangerous cells and malignant neoplasms. With the help of histological examination, all tissues and internal organs of a person can be studied in detail. The main advantage of this method is that with its help you can get the most accurate result. In order to study the structure of the kidney, histology is also one of the most effective examinations.

What is histology?

Methodology for collecting material for histology

As described above, histology is the study of a sample of human material under a microscope.

To study tissue material using a histological method, the following manipulations are performed.

When a kidney is examined (histology), the drug must be indicated under a specific number.

In some cases, when the situation is urgent and urgent histology of a human kidney is required, laboratory technicians may resort to a rapid test. In this case, the collected material is pre-frozen before cutting the sample. The disadvantage of such manipulation is that the results obtained will be less accurate. The rapid test is only suitable for detecting tumor cells. At the same time, the number and stages of the disease must be studied separately.

Methods for collecting analysis for histology

How is a kidney cut (histology)?

How is the procedure for collecting material for kidney histology performed?

What exactly are they doing?

It is worth noting that in some cases I can inject a certain substance into the patient’s vein, which will show all the most important blood vessels and the kidney itself.

In what cases can kidney histology be prescribed?

If acute or chronic defects of unknown origin are identified;

For complex infectious diseases of the urinary tract;

If blood is detected in the urine;

With high uric acid;

To clarify the defective state of the kidneys;

If the kidney that was previously transplanted is unstable;

To determine the severity of a disease or injury;

If there is a suspicion of a cyst in the kidney;

If a malignant neoplasm in the kidney (kidney cancer) is suspected, histology is mandatory.

What complications may arise when taking material for research?

Possible bleeding. In this case, an urgent blood transfusion is necessary. In rare cases, surgery will be required to further remove the damaged organ.

Possible rupture of the lower pole of the kidney.

In some cases, purulent inflammation of the fatty membrane around the organ itself.

Bleeding from the muscle.

If air enters, pneumothorax may develop.

Infectious infection.

How is the postoperative period going?

People who are about to undergo this manipulation should know a few simple rules for the postoperative period. You should follow your doctor's recommendations exactly.

What should a patient know and do after a histology procedure?

In what cases is it not recommended to collect material for histological examination?

There are several contraindications for collecting material for research, namely:

If a person has only one kidney;

If there is a blood clotting disorder;

If a person is allergic to novocaine;

If a tumor was found in the kidney;

With thrombosis of the renal veins;

For kidney tuberculosis;

In case of renal failure.

If a person suffers from at least one of the above ailments, then taking material from the kidneys for histological examination is strictly prohibited. Since this method has certain risks of developing serious complications.