Urinary system

Human body consists of cells, tissues, organs and systems. In the whole organism abjection of system of organs especially conditional as functionally all systems are interconnected.

System of organs represents set of many organs educing from the general germ, carrying out the general function and topographicallies of the interconnected.

One of organism systems is the urinary apparatus which carries out function of deducing of the solved toxicants unnecessary an organism; regulates a blood chemical compound. Uropoiesis processes are closely bound to a blood flow through a nephros. In abjection of metabolic products participate as well other organs: lungs (deducing of dioxide of Carboneum, a quantity of volatiles and water pairs); a skin, in particular, sudoral glands (deducing of water, the salts, some organic matters), an intestine (deducing of some salts as a part of a feces).

Urinific organs

Nephros

Nephros represents an organ where it is developed wetting. End products of proteometabolism of an organism in the form of urea, urinary acid, a creatinine, products of incomplete oxidation of organic matters (acetonic bodies, milk and acetoacetic acids), salts, the endogenous and exogenous toxic materials solved in water, mainly leave from an organism through a nephros. The small part of these materials is deduced through a skin and mucosas. Therefore nephroses along with the lungs excreting a carbon dioxide, represent the pivotal organ through which purification from products of an exchange final and unnecessary an organism is carried out. Without delivery of nutrients from the outside the organism can exist long time, without deducing of excreta perishes for 1-2 days. The remarkable constitution of a nephros is fitted so, that through biological membranes in urinary pathes inpour only materials unnecessary an organism. In a nephros at capillary level there was a close mutual relation between veins and urinary canaliculuses. The excreta which are in blood in small concentrations, inpour through a vascular side into urinary canaliculuses.

Choronomic constitution of a nephros.

A nephros - a didymous organ of the fabaceous form. Its length of 10-12 sm, width of 5-6 sm, a thickness of 3-4 sm, mass of 120-200 gramme. The left kidney is a little bit longer right and sometimes has larger weight. Colour of nephroses more often dark brown. Outside edge convex, intrinsic - bent. At intrinsic edge there is an excavation where the hiluses renalis conducting in its sinus are formed. In collars and a sinus calyxes, pelves, an ureter, an artery, a vein and absorbent vessels settle down. If to survey the attitude of pots, a pelvis and an ureter the vein in front settles down, then an artery and a pelvis. All these formations are concluded in a fatty and quaggy copulative tissue of a renal sinus.

Top extremity of a nephros more acute, than inferior, its forward surface is more convex, than back.

Intrinsic constitution of a nephros

On a cut of nephroses it is visible, that they consist of cerebral and cortical material of various density and colour; marrow is more dense cortical, some is bluish-red colour, cortical - zheltovato-red; these differences depend on an unequal blood filling.

Cortical material settles down outside and has a thickness 4 - 5 mm. Marrow forms 15 - 20 pyramidions, the wide establishment turned to cortical material, and a narrow part (apex) - to a nephros sinus. At coalescence 2 - 3 apexes of pyramids are formed a papilla which is surrounded by a small renal calyx. Between cortical and marrow there is no equal border. Into marrow between pyramidions inpours a part of cortical material in the form of columns, and into cortical material inpours marrow in the form of its radiant part. The layers of cortical material which are between radiant parts, consist of a convolute part. The radiant and curtailed parts form a lobe of cortical material. A reniculus - the part of cortical material corresponding to the establishment of marrow and accurately excreted at children.

Veins and urinary canaliculuses take part in formation cortical and marrow.

Renal artery in diameter 7 - 9 mm begins from a ventral aorta and in hiluses renalis is parted on 5 - 6 branches referred to its top, inferior poles and the central part. Into material of a nephros between pyramidions inpour interlobar arteries which at the establishment of pyramids come to an end with arc arteries. Arc arteries settle down on border cortical and marrow. From arc arteries two kinds of pots are formed: one are referred to cortical material in the form of interlobular arteries, others - in marrow where vascular capillars for blood supply of nephronic loops are formed. Interlobular arteries are parted on bringing arterioles which pass in the vascular glomuluses having diameter 100 - 200 microns. Vascular glomuluses represent a network of the vascular capillars which are carrying out function not of a histic exchange, and a filtration of excreta. Vascular capillars of a glomulus collect in its collars in bearing arteriole. The bearing arteriole of a glomulus has diameter smaller, than an afferent artery. The difference of diameters of arterioles promotes maintenance of a high blood pressure in glomulus capillars that is a necessary condition in the course of an uropoiesis. The bearing pot of a glomulus is parted on capillars which form dense networks round urinary canaliculuses and only then pass in venules. Venous pots, except for a vascular glomulus bringing arterioles and bearing arterioles, repeat branching of arteries.

Second important element of a nephros is the urinific system named a nephron. The nephron begins blind dilating - a two-wall capsule of a glomulus, which inlay one layer of a cubic epithelium. As a result of bond of a capsule of a glomulus and a vascular glomulus new functional formation - a renal little body is formed. Renal little bodies 2 million From a glomulus capsule is the gyrose canaliculuses of 1st order passing in the descending part of a nephronic loop begin. The ascending part of a nephronic loop passes in gyrose a canaliculus of 2nd order which joins direct canaliculuses. The last are collective tubes for many gyrose canaliculuses of 2nd order. Direct canaliculuses in marrow run into papillary ducts which at papilla fastigium form a trellised field.

Thus, veins, urinary canaliculuses and a surrounding copulative tissue form material of a nephros. From this follows, that the cortical material develops of the interlobular arteries, the bringing arterioles, bearing arterioles, renal little bodies, capillars and loops of urinary canaliculuses, direct and collective tubules.

In each renal little body it is excreted for days of primary urine of 0,03 ml. Its formation probably at a blood pressure about 70 mm hg At a blood pressure below 40 mm hg an uropoiesis is impossible. At huge number of renal little bodies of primary urine it is formed about 60 l a day; it contains 99 % of water, 0,1 % of a glucose, salts and other materials. From the primary urine which has passed through all parts of an urinary canaliculus, the reabsorbtion of water and a glucose in vascular capillars is made. Definitive urine in volume 1,2 - 1,5 l a day through collective tubules streams in small calyxes of a renal pelvis.

Age features. At the newborn borders of lobes are is better visible. By the moment of a birth and after it the first months formation of new nephrons still proceeds. In relation to body mass on unit of a surface of a nephros at children it is necessary more glomuluses, than at the adult. Despite it, filtrating power of glomuluses more low, than at the adult that is caused by smaller volume of glomuluses and thicker epithelium of a renal capsule. The canalicular reabsorbtion also is lowered. By 20 years growth of mass of a nephros for the account of augmentation of the dimensions of renal little bodies and length of urinary canaliculuses comes to an end.

Nephros covers

With cortical material of a nephros the fibrous capsule from which the tender connective tissue interlobular layers begin, invisible grows together with a simple eye. Besides connective tissue fibers, in a capsule there is badly expressed layer of unstriated muscles. For the account of their insignificant reduction interstitial pressure of a nephros that is necessary for filtration processes is sustained.

Nephros is shrouded by an adipose capsule consisting of a quaggy copulative tissue where at a superfluous food Adeps is postponed. The nephros adipose capsule is is better educed on its back surface and has certain value in nephros deduction in lumbar range. At a weight loss when Adeps in an adipose capsule disappears, there can be a motility of a nephros (a vage nephros).

Most outside cover is the renal fascia representing a two-layer plate. Forward and back leaves of a renal fascia at outside edge and the top pole of a nephros are bridged, and below in the form of a case proceed on an ureter to a bladder. At intrinsic edge fascial leaves ahead and behind pots in 70 % of cases are bridged to leaves of other party.

Nephros is kept in a niche of the lumbar range formed by the big lumbar muscles, a square muscle and a lumbar part of a diaphragm; covers of a nephros which have the numerous connective tissue fibers bridging a renal fascia, an adipose capsule and a fibrous capsule; nephros veins, and positive intraperitoneal pressure.

Topography. Nephroses settle down in retroperitoneal range on each side a column. The syntopy and a skeletopy of the right and left nephroses are various. The top pole of a left kidney is at level of XI thoracal vertebra, inferior - between II and III lumbar vertebra. XII rib crosses a left kidney in range of hiluses that is a good reference point at surgical access to a nephros. The right kidney settles down on 3 sm more low, than left.

Top extremity the nephros adjoins to an adrenal. A right kidney adjacent to a liver and a descending part of a duodenum, and its inferior extremity - to the right flexure of a small bowel. The left kidney adjoins to a stomach, a lien and a descending part of a colon. The root of a mesentery of a cross-section colon crosses a nephros in the middle.

Age features. At the newborn the nephros rather more than at the adult, has more round form with accurate borders of 14 lobes. The nephros of the newborn settles down on one vertebra more low, than at the adult. The intrinsic constitution is characterised by that the sinus and a cortex are badly educed, nephros marrow is well educed. Under a capsule renal little bodies lie down. Gyrose canaliculuses are educed badly, nephronic loops do not fall outside the limits cortical material. The nephros passes three stages of the enhanced growth: on 1st, 7th and 14th year of life.

Embryogenesis. On I month of development of an embryos on a back side of a trunk there are the didymous sexual and urinary ducts, reporting a secondary perigastrium with a cloaca. Sexual ducts concern development of nephroses. The embryos consistently has occurrence of a pronephrous, a primary nephros and a definitive nephros. Each nephros educes independently from each other from an unsegmented mesoderm. These nephroses in the embryonal season reflect only phylogenetic development of urinific organs. The pronephrous functions on 3rd week of embryonic development during 40 - 60 hours. It is presented 8 - 10 protonephridiums (urinary canaliculuses) which are discovered by one extremity in a perigastrium, and another - in Wolffian duct. In a side of protonephridiums there is a similarity of a renal capsule in which the loop of the vascular capillar growing from an abdominal part of an aorta is dipped. The nephros of a similar constitution exists at the lowest water animals.

Average nephros arises on 3 - 4th week of embryonic development and functions during 12 - 15 days. Urinary canaliculuses (nephridium) is nearby 20. At the majority of urinary canaliculuses the report with a secondary lumen is absent, and what still had these reports, in a foramen mouth have cilia. Fluctuating, they refer an urine current to a sexual duct. Urinary canaliculuses have deeper capsule where there is a vascular glomulus.

Development of a definitive nephros descends, since II month of embryonic development, from the metanephrogenic tissue which are in pelvic range on a place of transition of somites in lateral plates. From a final part of a sexual duct there is a blind diverticulum of the future ureter and a pelvis. Blind diverticulum Wolffian duct grows into a germ of a definitive nephros. From the blind extremity of an ureter in a depth of a metanephrogenic tissue calyxes and collective tubules of marrow of a nephros educe a pelvis. Simultaneously in a metanephrogenic tissue there are tubules, inlay a high epithelium; tubules growing, will be transformed to a capsule of glomuluses of a nephros. Then there comes process of bond of tubules with the collective tubules which are derivatives Wolffian duct.

Anomalies of development of nephroses meet in the form of an adnation of nephroses is more often.

Phylogenesis. The embryonic development at backboned pronephrouses, average and definitive nephroses actually repeats phylogenesis of organs of abjection. The lowest hearts which do not have a secondary perigastrium, in tissues have urinary tubules (protonephridiums) which deduce outside products of an exchange and sex cells.

The higher hearts and bloodsuckers in connection with development of a secondary perigastrium in each segment have urinary tubules - metanephridiums which are discovered by one extremity in a perigastrium, and another - on its surface and deduce products of an exchange and sex cells. Similar urinary canaliculuses function throughout life at cyclostomeses, fishes and amphibians.

Since a class of reptiles, a constant organ of abjection is the definitive nephros. At many animals of a pyramid and a lobe are abjointed from each other deep sulcuses.

Urinary organs

Renal pelvis

Definitive urine streams in the small calyxes representing excrescences of a pelvis which cover a nephros papilla. Two - three small calyxes merge in the big calyxes, and they in turn form a nephros pelvis. The pelvis passes in an ureter. Small, big calyxes and a pelvis settle down in a renal sinus.

Pelvis is behind nephros veins. Its form is rather various. The ampullar pelvis has one wide lumen and short calyxes. The long pelvis is small, and calyxes are extended. The branched out pelvis consists from 2 - 3 lumens intercommunicating with long calyxes.

Side of a pelvis and calyxes consists of mucous, muscular and connective tissue covers. The muscular coat at the establishment of small calyxes is educed better, than in other parts, and forms a sphincter. For the account of reduction of a muscular coat of a pelvis there is an accumulation of a portion of urine in volume 2 - 3 ml which is thrown out in an ureter.

Ureter

Ureter - the didymous tubular organ, reporting a pelvis of a nephros with a bladder. Length of an ureter 30 - 35 sm, diameter irregular; at a place of a discharge from a pelvis, at an orifice in a small basin and at transit through a bladder side, it is peer 3 - 4 mm, and between these narrowings its diameter reaches 9 mm. The ureter consists from mucous, muscular and outside connective tissue covers. The muscular coat has circular and longitudinal layers. In an ureter distinguish an abdominal part, a pelvic part and the intraparietal part which is in a side of a bladder. The abdominal part is behind a parietal layer of a peritoneum ahead of a fascia and a lumbar muscle. The right ureter in initial part is covered by a descending part of a duodenum, at the left - settles down under a root of a mesentery of a sigmoid intestine. At level articulatio sacroiliaca the abdominal part of an ureter passes in the pelvic.

In a basin the ureter lays behind a peritoneum and goes in parallel intrinsic ileal artery, crossing bearing duct at men, and then runs into a back side of a bladder. At women the pelvic part of an ureter settles down behind an ovary, medial an obturator artery and behind a uterine artery, being in the establishment of wide uterine ligament, and then, alighting in parallel a uterus, bends around a vagina part in front and enters a bladder. Hence, to a pelvic part of an ureter operational accesses through a vagina are possible.

The intraparietal part of an ureter has length 2 - 2,5 sm both passes behind forward and medially through a back side of a bladder. Comes to an end with a foramen covered from a lumen of bladder from above by a cord of a mucosa. The cord carries out a role of the semilunar valve and passes a portion of urine only from an ureter in a bladder; the retrograde current of urine in an ureter is impossible.

In an ureter distinguish three flexures and three narrowings: on a place of transition of a pelvis in an ureter, at transition of an abdominal part in pelvic and before occurrence in a bladder side.

Age features. The ureter long and bent, quickly grows and in the end of 2nd year of life its length doubles. The definitive length of an ureter is established by 30 years. Diameter of an ureter at children rather is less, than at the adult, has not absolutely accurately expressed places of narrowing.

Function. Urine moves on an ureter thanks to a peristalsis of its muscular coat. The wave of reductions repeats 1 - 5 times a minute with rate 2 - 3 sm a minute.

Bladder

Bladder - a bursiform organ, has an apex; below an apex to a place of a confluence of ureters in a bladder the body, from ostium an ureter prior to the beginning of an urethra - is excreted a bottom.

Side consists of mucous, muscular and connective tissue covers. The back side is covered by a peritoneum parietal layer. The mucosa is covered by a transitive epithelium. Own connective tissue layer of a mucosa is well educed and presented by a quaggy tissue which at a bladder evac easily collects in cords. These cords usually accept for cords of a submucosal layer, actually a submucosal layer in bladder is absent. Nearby ostium ureters also there are mucosa cords. Opposite to an intrinsic foramen of an urethra the uvula of bladder bridged to a crest of an urethra acts. The vesical triangle represents a part of a bottom of the bladder, circumscribed from above foramens of ureters (the triangle establishment) and between them an interureteric cord and an intrinsic foramen of an urethra (triangle fastigium). In the field of a vesical triangle mucous smooth also contains the cryptas sometimes accepted for glands.

Normal mucosa of a bladder at all does not soak up urine.

In a muscular coat is conditional excrete three layers: two longitudinal (outside and intrinsic) and circular. More appreciable development reach outside longitudinal and circular layers. In the field of a triangle of a bladder muscular layers are densely adherent with each other and with a mucosa. On a forward side the longitudinal muscular layer is bridged at men to a symphysis, on a back side - a prostate, at women - with a forward side of a vagina and an urethra.

Unstriated muscles of bladder at the beginning of an intrinsic foramen of an urethra form a sphincter. Thus muscle bundles cover a bottom of a triangle of a bladder, then on its lateralis parties reach foramens of an urethra and are thrown through a forward side of the canal in the form of a loop. At women the intrinsic sphincter is adherent with a forward side of a vagina, therefore the colporrhesis often causes damage of a sphincter and emiction disturbance. Urethra short circuit descends at reduction of a muscular loop. In this case the forward side of an urethra nestles on its back side, and also to a vesical uvula. The sphincter is reduced reflex without participation of consciousness of the human.

On an outside surface of a bottom of a bladder is rectovesical excavation, representing an independent fascicle which at men from a back side of a bladder passes to a rectum, and at women - on a uterus and a vagina. As a part of this muscle there are also transversely striated fibers.

Connective tissue layer surrounds a bladder from different directions, forming a paravesical fat. In a paravesical fat settle down venous and neuroplexes. The back side of bladder, especial at its filling, becomes covered by a serous cover.

Ligaments. The median umbilical ligament representing the reduced urinary duct departs from a bladder apex in a belly-button direction. The ligament is covered by a peritoneum which forms the cord with the same name.

Pubic-vesical, lateral and medial ligaments represent a part of a pelvic fascia. In their structure there are muscle bundles.

Topography. The bladder settles down in a small basin behind a symphysis. The empty bladder can be palpated at men only through a rectum, and at women - through a vagina. The bottom of a bladder settles down on a fascia and perineum muscles. At women in connection with wider and low perineum, than at men, the bladder also is more low. The filled bladder inpours between vesical fascia and a parietal layer of a peritoneum of a forward side of a gaste. At overflow by urine the bladder apex can reach a belly-button.

Age features. At children the bladder because of a small pelvic cavity settles down in an abdominal lumen and has the spindle-shaped form. The bottom of bladder is absent, and the bladder triangle is upright, alights to a basin only with pelvic cavity development that comes to an end to the puberty season. In view of high standing of bladder at girls it does not adjoin to a uterus and a vagina, and at boys - with a rectum.

Emiction mechanism

Vesical reflex arises when pressure in a bladder lumen exceeds 15 sm of a water column. At this pressure there is a boring of nerve terminations of eisodic fibers which as a part of pelvic nerves and hypogastric nerves transfer impulses in sacral segments of a spinal cord. From a spinal cord reciprocal impulses to a muscle of a side of a bladder are referred, causing its reduction. After a bladder evac the parasympathetic centre is oppressed, and sympathetic - provokes. As a result the tonus of a side of bladder weakens, and the sphincter is reduced.

In a vesical reflex the certain role is played by the inferior segment of a direct muscle of a gaste which adjoins to a forward side of a bladder. At reduction of a direct muscle of a gaste bladder is squeezed, pressure in it raises, and the vesical reflex comes faster.

At the human desires on an emiction arise in the event that the arbitrary sphincter of an urethra is occluded. At men owing to features of a constitution of a perineum and more powerful development of sphincters the ischuria is possible more long time, than at women.

Embryogenesis. The bladder educes on II month of the embryonal season from a cloaca and allantois part. The cloaca settles down on the caudal extremity of a trunk and represents an excavation where sexual both urinary ducts and an intestinal tube are discovered. Then the cloaca niche is parted by a face-to-face septum, being bridged with a membrane covering a cloaca. As a result the cloaca is parted on a forward genitourinary sinus and a back proctal sinus. With isolation of sinuses the membrane breaks, and the conforming foramens are formed. The allantois which consists of an apex, is bridged to a genitourinary part of an average part and a bottom. The allantois apex will be transformed to ligament, the average part and a bottom form a bladder.

Anomalies. Frequent anomaly is the report of a bladder with an umbilical foramen or an eversion of bladder a mucosa (ectopia). This anomaly reflects feature of development of bladder. The report of a bladder with a vagina or a rectum is observed also.

Phylogenesis. At water animals, amphibians, reptiles, cloacal, auks and some mammals the bladder is absent, and ureters are discovered in a cloaca. The similar picture of a constitution of urinary system and a cloaca is observed at the higher mammals only in an embryogenesis on II month of development. Absence of a bladder at the above-stated animals is bound, possibly, with feature of an exchange of proteins when an exchange end product is not only an ureapoiesis, but also urinary acid. Urinary acid easily crystallises unlike urea which long time can be in the solved condition. In the presence of a bladder at these animals conglomerates would easily be formed of urinary acid. Possibly, it was one of the causes which promoted a bladder reduction. Only at mammals who of ammonia have an urea synthesis, it is easy and it is long kept in the solved condition, the volume bladder was formed. At mammals the cloaca disappears and males between a sexual sine and the canal of a copulative organ have a report in the form of an urethra through which follows wetting and there pass sex cells.

Female urinary canal

Female urethra carries out functions only urine deducing. At men through an urethra passes not only urine, but also seed fluid.

Urethra of the woman has length of 3-4 sm, diameter of 7-11 mm. The canal is slightly bent, as passes through a genitourinary diaphragm of a perineum, settling down under a symphysis. In a place of transit of the canal through a perineum there is the outside sphincter, subordinated to consciousness of the human. The forward side of the canal is adherent with angle ligament of a symphysis, and a back side - with a forward side of a vagina. The canal has mucous, muscular and connective tissue covers. In a canal mucosa mucous glands are located. The outside foramen of an urethra is discovered in an entrance of the vagina, above an orifice in it. The Muscular coat forms an intrinsic sphincter.

Man's urinary canal

Man's urethra has length about 18 sm; its most part mainly passes on a spongiform body. The canal begins an intrinsic foramen in a bladder and comes to an end on a head. The urethra is sectioned into prostatic, webby and spongiform parts.

Prostatic part corresponds to length of a prostate and inlay a transitive epithelium. In this part distinguish the narrowed place, according to position of an intrinsic sphincter of an urethra, and more low a venter in length of 12 mm. On a back side of a venter the seed seminal hillock from which upwards and downwards the crest formed by a mucosa departs takes places. Around ostium ejaculatory ducts which are discovered on a seminal hillock, there is a sphincter. In a tissue of ejaculatory ducts there is a veniplex which carries out function of an elastic sphincter.

Webby part represents the shortest and narrow part of an urethra; it is well fixed in a genitourinary diaphragm of a basin and has length of 18-20 mm. Transversely striated muscular fibers round the canal form the outside sphincter, subordinated to consciousness of the human. The sphincter, except the emiction certificate, is constantly reduced.

Spongiform part has length of 12-14 sm and corresponds to a spongiform body. Begins bulbar dilating where ducts of two lukovichno-Urine emission glands excreting albuminous slime for humidifying of a mucosa and a colliquation of seed fluid are discovered. Bulbourethral gland in size about a pea settle down in a depth of a deep cross-section muscle of a perineum. The urethra of this part begins from bulbar dilating, has peer diameter of 7-9 mm and only in a head passes in the spindle-shaped dilating named a navicula which comes to an end with the narrowed outside foramen. In a mucosa of all parts of the canal there are numerous glands of two types: intraepithelial and is alveolar-tubular. Intraepithelial glands on structure are similar to goblet mucous cells, and is alveolar-tubular - have the form of flasks, выстланы a cylindrical epithelium. These glands excrete a secret for mucosa humidifying. The mucosa basal membrane is adherent with a spongiform layer only in a spongiform part of an urethra, and in other parts - with smoothlymuscular layer.

By treating of a profile of an urethra two curvatures, three dilatings and three narrowings are excreted. Forward curvature is in range of a root and is easily corrected at lifting. The second curvature is fixed in the field of a perineum and bends around a pubic symphysis. Canal dilatings: in a prostatic part - 11 mm, in bulbose parts - 17 mm, in a navicula - 10 mm. Canal narrowings: in the field of intrinsic and outside sphincters there is a full short circuit of the canal, in the field of an outside foramen diameter decreases to 6-7 mm. Thanks to distensibility of a tissue of the canal if necessary it is possible to spend a catheter in diameter to 10 mm.