Excretory systemExcretory system Systema urinarium Systema urinarium

KidneysKidneysRenesRenes

Overview of excretory systemOverview of excretory system

Upper excretory system• Kidney (Ren)

– Nephron (Nephron)– Collecting tubuli (Tubuli colligentes)

Lower excretory system– Renal calices (Calices renales)– Renal pelvis (Pelvis renalis)

• Ureter (Ureter)• Urinary bladder (Vesica urinaria)• Urethra (Urethra)

Kidney = RenKidney = Ren• greek nephros

– pl. nephroi• 150 g• facies anterior +

posterior• extremitas superior +

inferior• margo medialis +

lateralis • hilum renale• sinus renalis• capsula fibrosa• lobi renales

Kidney – Kidney – internal compositioninternal composition

• cortex: – labyrinthus– columnae renales

protrudes into medulla

• medulla: – pyramides renales →

papillae renales • area cribrosa + foramina

papillaria

– zona interna– zona externa

• stria interna + externa

– radii medullares protrudes into cortex

http://doctorstock.photoshelter.com/image/I0000zjcQLOxaHqY

Position, fixation and renal coversPosition, fixation and renal coversTransversal section at the level Th1

Impressions on the anterior face of kidney

Suprarenal gland

Liver

Flexura coli dextra

Suprarenal gland

Stomach

lien

Posterior kidney side impressions

Kidney syntopy, posterior side

Left RightDiaphragm

Kidney Kidney

microscopic microscopic structurestructure

• nephron

• interstitium

• vessels

NephronNephron

• Renal corpuscle

• Proximal tubule

• Intermediary tubule

• Distal tubule

• Juxtaglomerular apparatus

Renal corpuscleRenal corpuscleCorpusculum renale MalpighiCorpusculum renale Malpighi

• glomerulus (vascular convolut)– polus vascularis (vascular pole)– arteriola glomerularis afferens (wider) arteriola

glomerularis efferens (narrower)– fenestrated (70-100 nm) capillaries w/o diaphragma

• capsula glomerularis (Bowmans pouch)– stratum parietale = parietal sheet

• Flat single layer epithelium (epitheliocyti parietales)

– stratum viscerale = visceral sheet• podocytes

• spatium capsulare / urinarium– polus urinarius / tubularis (urinary pole)

Renal corpuscleRenal corpuscleCorpusculum renale MalpighiCorpusculum renale Malpighi

• podocytes– trabecules (cytotrabeculae) – primary

extensions– pedicles (cytopediculi) – secondary

extensions

• Basal membrane• mesangium (mesangium)

– Mesangial cells (mesangiocyti) • phagocyting, contractile and mitoting cells

– mesangial matrix

Philtration barrierPhiltration barrier= barrier blood-urine (glomerular philter)3 layers:• Endothelium of glomerular capillaries• Basal membrane

– lamina rara interna + lamina densa (collagen IV, laminin fibronectin, heparan sulphate) + lamina rara externa

• Pedicles of podocytes– Interdigitates among and form philtration cleft covered

by cleft membrane – diaphragma rimae (nefrin)- Other issues: size (10 nm) and substance charge → water permeable, low molecular substances → retain plasma proteins and blood cells

Mesangial cells (Mesangial cells (mesangiocytimesangiocyti) )

• File of cells of mesenchyme origin• Adjacent to capillary wall of glomerulus

A: intraglomerular (= pericytes)– contractile function – got receptors for angiotenzin II

and natriuretic factor (ANF)– Skeletal function– Synthesis of mesangial matrix and collagen– fagocytosis– proliferation

B: extraglomerular mesangial cells – Form part of juxtaglomerular apparatus

Renal tubules 1.Renal tubules 1.

• Proximal tubule (tubulus proximalis)– Convoluted part (pars convoluta)– Straight part (pars recta)

• middle / intermediate tubule (tubulus intermedius) – Descending part (pars descendens)– Ascending part (pars ascendens)

• Distal tubule (tubulus distalis)– Convoluted part (pars convoluta)

• macula densa

– Direct part (pars recta)

Proximal tubuleProximal tubule

• Single layer cuboid epithelium– Brush border on luminal side– Striation on basal side = basolateral labyrinth

(Na+-K+-ATPase)– Rich on mitochondria

• Resorption of NaCl and water (80-95 %), glucose, aminoacids and proteins– Na+ into cell passively, from the cell activelly

Middle / intermediate tubuleMiddle / intermediate tubule

= thin part of Henle loop

• Flat cells, poor on organels– Descending branch permeable for water– Ascending branch not permeable for water

• juxtamedular nephrons have long Henle loop– Countercurrent system (together with vasa

recta)

Henle loopHenle loopAnsa nephroni HenleiAnsa nephroni Henlei

• Formed by 3 morphological parts:– pars recta tubuli proximalis– tubulus intermedius– pars recta tubuli distalis

• Different length:– Juxtamedullary nephrons have long loop – Cortical nephrons have short loop

• 5x more compared to long ones

• parts:– Thick descending loop– Thin descending loop– Thin ascending loop– Thick ascending loop

Distal tubuleDistal tubule

• Single layer cuboid epithelium– Cells are smaller compared to proximal one– Lack of brush border– Striation on basal side = basolateral labyrinth

(Na+-K+-ATPase)– Rich on mitochondrias

• Back resorption of Na+ and secretion of K+– Regulated by aldosterone

• macula densa – chemoreceptors (Cl- and Na+)

Juxtaglomerulární aparátJuxtaglomerulární aparátComplexus juxtaglomerularisComplexus juxtaglomerularis

• granulární buňky arteriola afferens + efferens= juxtaglomerulární buňky (Juxtaglomerulocytus)– přeměněné svalové buňky tunica media– mechanoreceptory– inervace sympatikem– tvoří renin

• macula densa distálního kanálku (epitheliocytus maculae densae)– asi 30 štíhlých buněk– opačná polarita buněk– chemoreceptory

• mesangiální buňky (mesangiocytus extraglomerularis Goormaghtighi; Lacis cell)

• funkce:– regulace krevního tlaku – systém renin-angiotensin-aldosteron

(RAA)

InterstitiumInterstitium

• Connected with basal lamina of tubules and vessels

• cortical x medullary• Cell elements

• Fibroblasts similar cells• Cells with adipous particle• macrophages, pericytes

• Non cellular elements• proteoglycans, glycoproteins, interstitial fluid

Kidney tubules 2.Kidney tubules 2.

• Connecting tubule (tubulus reuniens)– Arch between distal and collecting tubule

• Collecting tubule (tubulus colligens)– Sigle layer cuboid epithelium

• Papillary duct (ductus papillaris)– Single layer columnar epithelium– Opens on area cribrosa papillae renalis

Collecting ducts (Collecting ducts (Tubuli colligentesTubuli colligentes))

• Principal cells (Epitheliocytus principalis)– Concentration of urine– Light cytoplasm, round nuclei

• Interstitial cells (Epitheliocytus intercalatus)– Secretion of H+ in exchange for K+ – Reabsorption of bicarbonate (karboanhydrasis)

• Regulation of water resorption – antidiuretic hormone (adiuretin, vasopressin) = ADH– aquaporins

Kidney – Kidney – arterial supplyarterial supply

• a. renalis – Paired visceral branch from aorta abdominalis at the

level of discus intervertebralis L1/2, left one higher

• a. renalis accessoria (30 %)– Branch of aorta abdominalis caudally, from a. iliaca

communis / interna

• Blood flow 1,2-1,3 l blood/min• Arteries are terminal type = no arterio-arterial

anastomoses

→ 5 kidney segments

Segments / parts of kidenySegments / parts of kideny

• segmentum superius

• segmentum anterius superius

• segmentum anterius inferius

• segmentum inferius

• segmentum posterius– Proper vessel

(r. posterior a. renalis)

Kidney – Kidney – arterial supplyarterial supply 2.2.a. renalis → r. anterior → 4 segmental branches → r. posterior for 1 posterior segmentaa. segmentales → aa. lobares (cca 12)→ 2-3 aa. interlobulares → 2 vertically running aa. arcuatae→ aa. interlobulares→ arteriolae glomerulares afferentes→ capillaries of glomerulus (glomerulus)

• Pressure in glomerular systém high (55 mmHg)

→ arteriolae glomerulares efferentes→ peritubular capillary mesh or arteriolae rectae along

intermediary tubules of juxtaglomerular nephrons• Pressure in the systém of peritubular plexus is low (15 mmHg)

Kidney – Kidney – venous drainagevenous drainage

• vv. stellatae (from surface)• + venulae rectae (along intemediary lubuls

of juxtaglomerular nephrons)• + peritubular capillary plexus →→ vv. interlobulares → vv. arcuatae → vv.

interlobares → v. renalis → v. cava inferior• Portal system (= rete mirabile)

– 2 concomitant serially arranged capillary bedstreams

• strong veno-venous anastomoses

Kidney – Kidney – lymph flowlymph flow

• 3 lymph plexus– peritubular, subcapsular and from capsula adiposa

• nodi lymphoidei lumbales

• plexus renalis– autonomous, viscerosensitive

– from ganglion coeliacum + plexus coeliacus– from ganglion aorticorenale from n. splanchnicus

minor/imus and plexus aorticus abdominalis

Kidney – Kidney – innervationinnervation

Resorptive function of kidneysResorptive function of kidneys

• Countercurrent multiplicatory system / mechanism– Different permeability of canals for water and salts– Drainage of interstitium by vasa recta

• Hormonal regulation– RAA: renin → (from angiotensinogen in blood)

angiotenzin I (enzyme ACE on endotelium in lungs) angiotenzin II (in kidney cortex)

– aldosterone– ADH– ANF

• Other kidney hormones: erytropoetin, kalcitriol

Countercurrent Countercurrent multiplicatory multiplicatory mechanism of mechanism of

kidneykidney

Countercurrent Countercurrent multiplicatory multiplicatory

mechanism of kidneymechanism of kidney

Kidney HEKidney HE

Kidney Van GiesonKidney Van Gieson

Kidney developmentKidney development

• předledvina = pronephros– nefunkční, „otevřená“

• prvoledvina = mesonephros– základ pohlavní žlázy

• konečná ledvina = metanephros

http://www.indiana.edu/~anat550/urrepanim/animations/gonad_dev.swfhttp://meded.duke.edu/symbrio/site/index.html#

Kidney developmentKidney development• Origin from intermedial mesoderm • Longitudinal elongation of mesoderm on both

sides of dorsal aorta → urogenital crest → nephrogenic strand → origin of urinary / genital system– Genital crest → origin of genital system

4 foundations of urinary system4 foundations of urinary system

• Metanephrogenic blastemanefron (Bowmans pouch and tubules)

• Ureteric bud – collecting tubules → ureter

• vessels – branches from dorsal aorta

• Cells from crista neuralis (regulation, secretion)

PronePronephphrosros

pl. pronephroi• Forms excretory systém in cyclostomatous

species (lamprey)• In human first description by Janosik• Stalks of cranial 12-13 somites• Since 21st day (4 somites) in cervical region• rudimentary, early ceases• tubuli pronephrici• ductus pronephricus premains until next stage

MesoneMesonephphrosros

• Excretory system of Chondrychties and fishes• Basic is nephrogenic blastem (intermediary

mesoderm)• Pouch elongates towards ductus mesonephricus

Wolffi– At the stage of 27-28 somites ingrowth to

cloaca• Since approx. 23rd day till the end of 3rd month

• corpuscula mesonephrica (glomerulus) + tubuli mesonephrici

• Caudal part of tubuli → basis of caput epididymidis

Ductus mesonephricus Ductus mesonephricus WolffiWolffi

• Originate in intermediary mesoderm• Blindly from up as outlet pronephroi• Caudally continues as outlet

mesonephroi• Finishes growth and opens into cloaca• Fundamental for development of male

reproduction outlet pathway• From caudal part is formed diverticulum

metanephricum (ureteral bud)

Ductus mesonephricus Wolffi (Prvoledvinný vývod)

• ♀ ureterální pupen → trigonum vesicae, ureter, pelvis renales, calices, ductus papilalles, tubuli colligentes– vývojové rudimenty: epoophoron, ductus

longitudinalis Gartneri

• ♂ totéž + vývodní pohlavní cesty (ductus epididymidis, ductus deferens glandulae vesiculosae, ductus ejaculatorius)

Male reproductive organsVesiculous

gland

Prostate

Bulbo-urethral gland

Penis

Urethra

Deferantial duct

Epididymis testisScrotum

MetaneMetanephphrosros = Definitive kidney = Definitive kidney

• blastema metanephrogenicum (metanephrogenic blastem) of 3rd-5th lumbar somite– Development start at the end of 5th week– During development there is relative ascension

• Ureteral bud growth in blastem – reciprocal induction (necessary close contact)

• Ureteral bud → ureter, pelvis renalis, calices, calliculi, papillary ducts till collecting tubules

• Metanephrogenic blastem – nephron• Relative ascension: 5th-9th week• Functional since 9th week

NephrogenesisNephrogenesis 8th week• Direct collecting tubules→ from these round collecting ducts→ its end induce metanephritic bodies• Spheroid body → line body → sigmoid body →

connection to branch of ureteric bud• Maturation of kidney body• Distance from glomerulus from medulla makes up for

age– Oldest are juxtamedulary nephrons

• Ends of collecting tubules elongate into metanephric tubules and joins collecting ducts

• Into opposing ends of metanephric tubule invaginate glomeruli

Development terminationDevelopment termination

• Terminal position in 9th week (termination of ascension)

• 10th-23rd week:– Quantity of glomeruli increases and reaches

its border (800 000 – 1 000 000)

• Kidneys of fetus are separated into visible lobes– Cessation during childhood

• After delivery growth of interstitium, elongation of tubules and Henles loops

Developmental defectsDevelopmental defects• Atypical shapes (lobular, horse shoe, doubled, sigmoid,

arcuate…)• cystic, polycystic kidneys• Agenesis of kidney• Dysplasia of kidneys• ectopia of kidneys (ren dystopicus)

Polycystic kidneysPolycystic kidneys

Prenatal diagnosticsPrenatal diagnostics

• Kidneys are visible by ultrasound since 12th-15th week• The goal is recognition of developmental defects

– dysplasia of kidneys, damage to kidney function, lung hypoplasia

• Oligohydramnion– Primary lesion of kidneys, secondarily of lungs (part of Potter

syndrome )

• Cystic dysplasia of kidney– Increased risk of Wilms tumor incidence (nephroblastoma)

• Hydronephrosis– Origin in obstructive nephropathias

Kidney examinationKidney examination

• native x-ray picture• sonography• Excretive urography• ascendent pyelography• scintigraphy• clearence• CT, MR

http://www.genesis-ultrasound.com/images/renal-ul-image.jpghttp://lunar.thegamez.net/medical/ultrasound-sonography/ru-ultrasound-image-description-kidney-640x480.jpg

Ultrasound of kidneyUltrasound of kidney

Scintigraphy of kidneyScintigraphy of kidney

http://www.kcsolid.cz/zdravotnictvi/klinicka_kapitola/nef/nef-5/nef-5-text.htm

http://www.jpalliativecare.com/viewimage.asp?img=IndianJPalliatCare_2013_19_1_58_110239_u6.jpg

SPECT – frontální řez

http://www.kcsolid.cz/zdravotnictvi/klinicka_kapitola/nef/nef-26/nef-26-text.htm

http://2.bp.blogspot.com/-QpHZioUD4jc/T3JDlfdhj0I/AAAAAAAAAOU/xT379opJgtM/s1600/Stone+CT.jpg

http://www.kidneystoners.org/wp-content/uploads/2012/02/pediatric-

kidney-stone-CT.jpg

MRIMRI

http://w-radiology.com/entero-mri-anatomy.php

Kidney diseasesKidney diseases• developmental defects• cysts (solitary x polycystic kidney)• ren migrans (migrating kidney)•glomerulonephritis• pyelonephritis• nephrolitiasis• renal colic• hydronephrosis• diabetes mellitus – nephropathy• tumors

• Grawitz (solitary metastasis)• Wilms (autosomally inherited – children)

• stenosis a. renalis

NephrolitiasisNephrolitiasis

Kidney diseasesKidney diseases • Diabetic nephropathyDiabetic nephropathy• Acute pyelonephritisAcute pyelonephritis