Urinary systemSystema urinarium

Anatomy + a glimpse of histology and embryology

Upper urinary tract

• Nephron

• Tubuli colligentes

Lower urinary tract

• Calices renales (Renal calices)

• Pelvis renalis (Renal pelvis)

• Ureter

• Vesica urinaria (Urinary bladder )

• Urethra feminina / masculina

Kidney (Ren, Nephros)• margo, hilum, sinus,

facies, extremitas /polus/

• capsula fibrosa, lobi renales

• Cortex: labyrinthus, columnae renales Bertini, radii medullares

• Medulla: pyramides renales → papillae renales (area cribrosa + foramina papillaria)– zona interna + externa

Position and fixation of kidneys

Synthopy and impressions

Kidney

Microcopic structure• Nephron• Interstitium• Vessels

Nephronfunctional unit

• Corpusculum renale Malphigi– glomerulus (vessel skein)

– capsula glomeruli Bowmani

• Proximal tubule• Intermediate tubule• Distal tubule• Juxtaglomerular apparatus

Corpusculum renale(ledvinné tělísko Malpighi)

• Capsula glomeruli (Bowman´s capsule)– parietal lamina (flat monolayer epithelium)

– visceral lamina (podocytes with pedicles)

• Glomerulus – vas afferens vas efferens (= arterioles)

– fenestrated capillars without diaphragm

• Filtration barrierbasal membrane - colagen IV. typ and heparan sulfatenegative charge

• Mesangial cells cleaning function of filter

Proximal tubule

• single layer of cuboidal epithelium rich in microvilli

• resorption of NaCl and water (80-95%)– Na+ passive transport into cells,

active transport out of cells

Intermediate tubulus

• = thin segment of ansa nephroni (Henle´s renal loop)

• descending and ascending limb• flat cells, few organels

– descending segment permeable for water– ascending not!!

• juxtamedullary nephrons with long H. loop– countercurrent together with vasa recta

Distal tubule

• cuboid eptihrelium with few microvilli

• back-resorption Na+ and secretion K-

• macula densa - chemoreceptors (Cl-)

• includes the thick segment of Henle´s loop

Juxtaglomerullar apparatus

• components– macula densa of distal tubulus– granullar cells (transformed smooth muscle

cells) of vas afferens + efferens– mesangial cells

• function– regulation of blood pressure

by hormone renin

Kidney - arterial supply I.

• a. renalis (paired visceral branch of abdominal aorta at level of discus intervertebralis L1/2, left L1)

• accessory renal artery (30%)

• rate flow 1,2-1,3 l blood/min

• arteries are terminated = no arterio-arterial anastomosis

Kidney - arterial supply II.a. renalis r. anterior 4 segmental branches

r. posterior for 1 dorsal segment

aa. segmentales a. lobares (about 12) 2-3 aa. interlobulares aa. arcuatae a. interlobulares arteriolae glomerulares afferentes glomerulus of capillars arteriolae glomerulares efferentes peritubullar capillary plexus or arteriolae rectae along intermediate tubulus of juxtaglomerullary nephrons

Kidney - venous supply

vv. stellatae (from surface) + venulae rectae (along intermediate tubulus of juxtaglomerullary nephrons) + peritubullar capillary plexus vv. interlobulares vv. arcuatae vv. interlobares v. renalis v. cava inferior

Portal system (= rete mirabile) – 2 capillary nets one after the other

migthy veno-venous anastomosis

Kidney Lymph drainage and innervation

• 3 plexus (peritubullar, subcapsullar and from adipose capsule)

• nodi lymphoidei lumbales

• plexus renalis (autonomous, viscerosensitive) from ganglion coeliacum + plexus coeliacus, from ganglion aorticorenale

• from n. splanchnicus minor and plexus aorticus

Kidney examination

• Native X-ray snap

• Sonography

• Excretory urography

• Ascending pyelography

• Clearence

• CT, MR

Kidney diseases• Development defects – agenesis, shape deformities• - cysts• Glomerulonephritis• Pyelonephritis• Hydronephrosis• Nefrohydrosis• Diabetes mellitus – nephropathy• Tumours

• Grawitz´s (solitary metastasis)• Wilms´ (autosomally heridatory - children)

• Renal colic

Development of urinary system

• Development of kidney– Pronephros– Mesonephros– Metanephros

• Development of urinary tract

Pronephros

• From intermediate mesoderm of cranial 12-13 somites

• from 21st day (4 primary segments)• rudimentary, disappears quickly• common presistent ductus mesonephricus Wolffi

Mesonephros

• origin from nephrogenic blastema

• sac elongates to ductus Wolffi

• approximately from 23rd day

• glomerulus and collective tubules

• caudal parts are origin for genital organs

• = urinary system of fish

Metanephros

• definitive stadium of kidney• nephrogenic blastema 3rd to 5th lumbar somites

– development begins at the end of 5th week– relative ascent during development

• ureteral bud sprins upwards from ductus mesonephricus Wolffi and grows in blastema

• induction of maturation of nephronureteral bud ureter, pelvis, calices, collecting

tubulesmetanephrogenic blastema nephron

Development malformations

• Atypical shapes• Cystic, polycystic kidneys• Agenesis of kidney • Ureter duplex, fissus

Kidney transplantation

• since 50s´

• 5 years of graft survival - 70%

• including proximal part of ureter and its blood supply (branches of renal vessels)

• placed to fossa iliaca and renal artery joined to a. iliaca ext. (end-to-side) or to terminal part of a. iliaca int. (end-to-end)

• if present, a. renalis accessoria joined to a. epigastrica inferior

Lower urinary tractgeneral wall structure

• Mucosa (tunica mucosa)– epithelium transitional– lamina propria mucosae (collagen)

• Smooth muscle (tunica muscularis)

• Adventitia (tunica adventitia)

Renal pelvis (Pelvis, pyelon) Renal calices (Calices renales)

• 7-14 calices minores around papilae 2-3 calices majores ureter

• ampullary / branching type (typus dendriticus)

• muscular layer – strong circular

• projection: processus costalis L1

• blood supply: branches of renalartery, tributaries to renal vein

Ureter • 25-30 cm, lumen 4-7 mm• 3 parts: pars abdominalis, pelvina, intramuralis• crossings of important structures• 3 constrictions – risk of stone impact

obstruction hydronephrosis afunction of kidney

• 2 muscular layers– inner longitudinal

– outer circular

• adventitia

Ureter - supply

• Arteries: a. renalis, aorta abdominalis, a. testicularis/ovarica, a. ductus deferentis / uterina, a. vesicalis inf. rr. ureterici

• Veins run along arteries

• Lymph drainage: nll. lumbales (aortici lat.), iliaci int., ext., communes

• Nerves: plexus uretericus  plexus renalis, aorticus abd., hypogastricus sup., inf.

Ascending (retrogade)

pyelography

Urinary bladder (Vesica urinaria, Kystos)

• description: fundus, corpus, apex, cervix, uvula

• trigonum vesicae – ostia ureterum, plica interureterica, ostium urethrae internum, Bell´s bands

• muscles: smooth– m. detrusor

(parasympathetic)– m. trigoni vesicae– ♂m. sphincter vesicae

(sympathetic)

• projection: behind symphysis pubica (in child over s.p.)

Cystography

Urinary bladder – wall structure

• folds except trigonum vesicae• smooth muscle fibres create 3 layers:

– inner plexiform– middle circular

m. sphincter vesicae in male only!– outer longitudinal

• upper surface covered with serosa (peritoneum) = partially intraperitoneal organ

Urinary bladder – supply

• a. iliaca int. a. umbilicalis aa. vesicales sup.• a. iliaca int. a. vesicalis inf.• (a. obturatoria, a. glutea inf., a. uterina, a.

vaginalis rr. vesicales) • Veins: plexus venosus vesicalis (connections to

plexus venosus prostaticus/vaginalis) vv. vesicales v. iliaca int.

• Lymph drainage: nodi paravesicales nodi iliaci int. et ext. nodi iliaci comunes

• Nerves: plexus vesicalis  plexus hypogastricus inf.

Urinary bladder - fixation• Ligaments: pubovesicale,

puboprostaticum, rectovesicale, vesicouterinum

• Smooth muscle: pubovescalis, rectovesicalis

• Ligamentum umbilicale medianum (= chorda urachi)

• Fascia vesicoumbilicalis Delbeti

• Septum rectovesicale Denonvilliersi

• Septum vesicovaginale• Spatium retropubicum

Reztii

Urinary bladder - peritoneum• Fossae paravesicales• ♂ excavatio

rectovesicalis= most caudal space of peritoneal

cavity in male (in contact with top of glandula vesiculosa)

♀ exc. vesicouterina♀ exc. rectouterina (=

Douglas´space)= most caudal space of

peritoneal cavity in female (in contact with top of posterior vaginal vault)

– palpation and puncture in inflammation via vagina !

Urethrae

• Male urethra is divided in 4 parts:– transitional epithelium in firts 2 parts– pseudostratified or stratifoed columnar

epithelium in the rest

• Female urethra – transitional epithelium in intramural part– squamous stratified

Urethra feminina (Female urethra)• 3 parts: pars intramuralis, pelvina, perinealis• ostium urethrae internum (trigonum vesicae)

– accipiens, evacuans• ostium urethrae externum (vestibulum vaginae)• crista urethralis, lacunae, glandulae urethrales

(Skenei s. Guérini), ductus paraurethrales (Schülleri)

• smooth muscles, around urethra striated m. sphincter urethrae, m. compressor urethrae a m. sphincter urethrovaginalis

• adventitia

Urethra feminina - supply

• Arteries: paired branches of a. vesicalis inf. et a. vaginalis

• Veins: plexus venosus vesicalis plexus venosus vaginalis vv. pudendae int. • Lymph drainage: nl.l. iliaci int., ext.• Nerves: plexus hypogastricus inf. plexus

vesicalis, plexus uterovaginalis nn. vaginales

Development of lower urinary tract

• Urinary bladder– developed from cranial part of urogenital sinus– urachus– separation of excretory urinary trct and genital

ducts

• Urethra♀ developed from medial part of urogenital sinus

♂ developed from medial and caudal part of urogenital sinus and glandular plate

Urine continence in female• no smooth muscle sphincter in urinary

bladder• elastic fibres + venous plexuses in urethra • striated muscle m. sphincter urethrae

(externus) /S2-S4/• so-called „periurethral muscles“ (in

increased intra-abdominal pressure)– m. levator ani (S3-S4)– m. compressor urethrae, m. sphincter

urethrovaginalis, m. bulbospongiosus (n. pudendus)

Urethra masculina (Male urethra)

• 4 parts

• see male genital system