Urinary system The urinary system an overview 2. Embryonic development kidney systems 3. The kidneys: 4. Renal anomalies

Transcription

1 Urinary system 1 1. The urinary system an overview 2. Embryonic development kidney systems 3. The kidneys: topography and macroscopic anatomy microscopic anatomy the nephron blood supply and innervation 4. Renal anomalies

2 The urinary system The urinary system, systema urinaria excretion of the end products of the metabolic activities urine The urinary organs, organa urinaria: kidney, ren: renal calyces minor and major renal pelvis ureter, ureter urinary bladder, vesica urinaria urethra, urethra: male urethra, urethra masculina female urethra, urethra feminina Prof. Dr. Nikolai Lazarov 2

3 Embryonic development Embryonicorigin fromcommonmesodermal ridge (intermediate mesoderm): urogenital ridge mesonephric ridge lateral part Kidney system: pronephros, Gr. pro-, earlier + nephros, kidney the earliest nephric stage in humans in the cervical region of the embryo nephrotomes begin 4 we. induction by the intermediate mesoderm via transcription factors Lim-1 and Pax-2 disappear by the end ofthe 4 th we. mesonephros, Gr. middle kidney (Wolffian body) begin 4 we., caudally to the pronephros mesonephric(wolffian) duct metanephros, definitive(permanent) kidney appears in the 5 th we. in the pelvis metanephric diverticulum (ureteric bud) metanephric mesoderm blastema o growth factors FGF-2, BMP-7 and LIF ureteric bud collecting system (ducts) Prof. Dr. Nikolai Lazarov 3

4 Embryonic development Embryonicorigin fromcommonmesodermal ridge (intermediate mesoderm): urogenital ridge mesonephric ridge lateral part Kidney system: pronephros, Gr. pro-, earlier + nephros, kidney the earliest nephric stage in humans in the cervical region of the embryo nephrotomes begin 4 we. induction by the intermediate mesoderm via transcription factors Lim-1 and Pax-2 disappear by the end ofthe 4 th we. mesonephros, Gr. middle kidney (Wolffian body) begin 4 we., caudally to the pronephros mesonephric(wolffian) duct metanephros, definitive(permanent) kidney appears in the 5 th we. in the pelvis metanephric diverticulum (ureteric bud) metanephric mesoderm blastema o growth factors FGF-2, BMP-7 and LIF ureteric bud collecting system (ducts) Prof. Dr. Nikolai Lazarov 4

5 Embryonic development Embryogenesis of the urinary bladder and urethra: anorectal canal posterior part of the cloacal membrane urogenital sinus, sinus urogenitalis: the upper part urinary bladder o the allantois urachus the middle portion o the prostatic and membranous parts of the male urethra o the whole female urethra the lower (phallic) part o the spongy part of the male urethra Prof. Dr. Nikolai Lazarov 5

6 Kidney, ren Kidney, ren (Gr. nephros): a paired organ excretory function: end metabolites excess water endocrine function: erythropoietin - red blood cell formation renin controlofbloodpressureandvolume 1,2,5-hydroxycholecalciferol control of the calcium metabolism Kidneys in situ: in the lumbar region in the posterior abdominal cavity, on the posterior abdominal wall in the retroperitoneal tissue Prof. Dr. Nikolai Lazarov 6

7 Macroscopic anatomy Kidney overview: shape bean-shaped size: two extremities: o superior and inferior extremity two surfaces and two margins: o anterior and posterior surface o lateral and medial margin renal hilum renal sinus renal calyces (~12) cm long ~6 cm wide ~3 cm thick weight 150g( );135g( ); 1/240 of the body mass color reddish renal consistency a parenchymal organ Prof. Dr. Nikolai Lazarov 7

8 Topography of the kidney Renal surface projections: the posterior abdominal wall 12 th thoracic vertebra 1 st and 2 nd lumbarvertebrae right kidney 1-2 cm inferior to the left Prof. Dr. Nikolai Lazarov 8

9 Kidney attachments Renal capsules: renal capsule, capsula fibrosa adipose capsule pararenal fat renal fascia (of Gerota), fascia renalis two layers prerenal fascia retrorenal fascia Prof. Dr. Nikolai Lazarov 9

10 Prof. Dr. Nikolai Lazarov 10

11 Imaging anatomy conventional radiography echography (ultrasonography) computed tomography (CT) magnetic resonance imaging (MRI) CT and MRI at the level of renal hilum Prof. Dr. Nikolai Lazarov 11

12 Renal relations Prof. Dr. Nikolai Lazarov 12

13 General renal structure Kidney structure: the renal cortex, cortex renalis 5-10 mm: outer reddish brown-colored part granular appearance: o pars convoluta o pars radiata (cortex juxtamedullaris) o lobulus corticalis the renal medulla, medulla renalis: much lighter-colored inner part renal pyramids, pyramides renales 7-20(12): o basis pyramidis o papilla renalis sinus renalis o foramina papillaria area cribrosa renal columns, columnae renales(bertini) renal lobes, lobi renales Prof. Dr. Nikolai Lazarov 13

14 Microscopic anatomy The nephron, nephronum 1-2 million: renal corpuscle (of Malpighi), corpusculum renale (Malpighi) the renal tubules: proximal (first) convoluted tubule, tubulus contortus proximalis U-shaped thin segment (loop of Henle), tubulus atenuatus (ansa nephroni) o descending limb, pars descendens o ascending limb, pars ascendens distal (second) convoluted tubule, tubulus contortus distalis collecting tubule, tubulus renalis colligens: o straight tubule (pars recta)and convoluted tubule (pars convoluta) Types of neuphrons: cortical or subcapsular nephrons, nephronum breve(corticale) intermediate, nephronum intermedium juxtamedullary nephrons, nephronum longum (juxtamedullare) Prof. Dr. Nikolai Lazarov 14

15 Microscopic anatomy Renalcorpuscle (of Malpighi), corpusculum renale (Malpighi) number 2 million,diameter200 µm: cortical glomerulus(80%) and juxtamedullary (20%) a tuft of capillaries, glomerulus rete capillare glomerulare (mirabile) vascular pole, polus vascularis urinary pole, polus tubularis afferent arteriole, vas afferens efferent arteriole, vas efferens mesangium renal or Bowman s capsule, capsula glomeruli (Bowman) visceral lamina, paries interna parietal lamina, paries externa capsular (urinary) space, lumen capsulae Prof. Dr. Nikolai Lazarov 15

16 Blood-urine barrier The kidney filtration apparatus semipermeable barrier glomerular filtrate = 170 l. primary urine: fenestrated capillary endothelium, lamina fenestrata endothelial cells, endotelocyti fenestrati o µm pores (fenestrations) with an absent diaphragm glomerular basement membrane, membrana basalis 30 µm lamina rara interna lamina densa lamina rara externa visceral layer of Bowman s capsule podocytes, podocyti µm o pedicels (foot processes), cytotrabecules and cytopodia o filtration slits 20-30nm o filtration slit membrane Prof. Dr. Nikolai Lazarov 16

17 Blood-urine barrier The kidney filtration apparatus semipermeable barrier glomerular filtrate = 170 l. primary urine: fenestrated capillary endothelium, lamina fenestrata endothelial cells, endotelocyti fenestrati o µm pores (fenestrations) with an absent diaphragm glomerular basement membrane, membrana basalis 30 µm lamina rara interna lamina densa lamina rara externa visceral layer of Bowman s capsule podocytes, podocyti µm o pedicels (foot processes), cytotrabecules and cytopodia o filtration slits 20-30nm o filtration slit membrane Prof. Dr. Nikolai Lazarov 17

18 The mesangium Mesangium (Gr. mesos, middle, + angeion, vessel): mesangial cells, mesangiocyti in islets, insulae perivasculares masangii supporting role produce the glomerular matrix contractile and phagocytic function contain receptors for angiotensin ІІ, ANF synthesize IL-1 and PDGF extraglomerular mesangial ( lacis ) cells polar cushion ; the juxtaglomerular apparatus Prof. Dr. Nikolai Lazarov 18

19 The renal tubules proximal convoluted tubule, tubulus contortus proximalis: length15µm;width50-60 nm parts: initial part, neck convoluted tubule, pars convoluta straight tubule, pars recta simple columnar epithelium brush border microvilli basal striations reabsorption of water and electrolytes, amino acids, sugars and polypeptides distal convoluted tubule, tubulus contortus distalis: shorter and wider parts: straight segment, pars recta convoluted, pars convoluta simple cuboidal epithelium striations short microvilli reabsorptionofna,kandwater juxtaglomerular apparatus Prof. Dr. Nikolai Lazarov 19

20 The renal tubules proximal convoluted tubule, tubulus contortus proximalis: length15µm;width50-60 nm parts: initial part, neck convoluted tubule, pars convoluta straight tubule, pars recta simple columnar epithelium brush border microvilli basal striations reabsorption of water and electrolytes, amino acids, sugars and polypeptides distal convoluted tubule, tubulus contortus distalis: shorter and wider parts: straight segment, pars recta convoluted, pars convoluta simple cuboidal epithelium striations short microvilli reabsorptionofna,kandwater juxtaglomerular apparatus Prof. Dr. Nikolai Lazarov 20

21 The renal tubules attenuated tubule (renal loop, loop of Henle), tubulus atenuatus (ansa nephroni): in the medulla(pyramids) parts U-shapedturn pars descendens 30 nm, simple squamous epithelium pars ascendens 60 nm, simple cuboidal to columnar epithelium in the thick segment single microvilli reabsorption of Cl - collecting tubule, tubulus renalis colligens: parts: arched collecting tubules, tubulus colligens arcuatus straight collecting tubules, tubulus colligens rectus simple cuboidal epithelium light (CD) cells aquaporin-1, 2 and 3 dark (intercalated or IC) cells simple bilayered(calyces) columnar epithelium basement membrane water reabsorption (ADH) small volume of hypertonic urine Prof. Dr. Nikolai Lazarov 21

22 Kidney as an endocrine organ The juxtaglomerular apparatus: juxtaglomerular cells: modified smooth muscle cells in the media of the afferent arteriole secretory granules(10-40 nm) renin absent internal elastic membrane macula densa: taller columnar cells o crowded nuclei o signaling molecules renin absent basement membrane extraglomerular mesangial(lacis) cells (Goormaghtigh cells) erythropoietin interstitial cells prostaglandins Prof. Dr. Nikolai Lazarov 22

23 Blood supply of the kidney Renal blood vessels: renal artery 70% of the arterialblood: aa. interlobares, aa. arcuatae et aa. interlobulares vas afferens accessory renal arteries 30% Prof. Dr. Nikolai Lazarov 23

24 Kidney segmentation Renal segments: segmentum superius segmentum inferius segmentum anterius superius segmentum anterius inferius segmentum posterius Prof. Dr. Nikolai Lazarov 24

25 Periarterial lymphatic network Perivenous lymphatic network Lymphatic network in the renal capsule left kidney lymphatic vessels around aorta right kidney lymphatic vessels around inferior vena cava Lymphatic drainage of the kidney Prof. Dr. Nikolai Lazarov 25

26 Nerve supply to the kidney Renal plexus: parasynpathetic vagus nerve sympathetic celiacandmesenteric ganglia somatosensory thoracic and lumbar spinal nerves Prof. Dr. Nikolai Lazarov 26

27 Renal anomalies Ectopic kidney: renal hilum below L 3 lumbar, iliac and pelvic kidney above Th 12 thoracic unilateral and bilateral renal ectopia horseshoe kidney ren atcuatus(1:600) cross fused renal ectopia congenital (inherited) acquired movable kidney Absence of kidney Accessory kidney Prof. Dr. Nikolai Lazarov 27

28 Thank you... Prof. Dr. Nikolai Lazarov 28