Uropoetic system

Histology and embryology

Uropoetic system

• Kidney (Ren)– Nephrone (Nephron)– Collecting tubules (Tubuli colligentes)– Callices (Calices renales)– Renal pelvis (Pelvis renalis)

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

Development of urinary system

• Development of kidney– Pronephros– Mesonephros– Metanephros

• Development of excretory passages

Pronephros

• Intermedial mesoderm of cranial 12-13 somites

• From 21st day (4 somites)

• Rudimental, soon disappear

• Persistent ductus Wolffi

Mesonephros

• From intermedial mesoderm

• Sac elongates to ductus Wolffi– In stage of 27-28 somites ingrowths to cloaca

• From about 23rd day

• With glomerulum and collective tubule

• Caudal part is origin for gonads

Metanephros

• Definitive stage of kidney• nephrogenic blastema 3rd to 5th lumb. somites

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

• Ureteral bud grows to blastema

• Ureteral bud – ureter, pelvis, large and small calices and collecting tubules

• metanephrogenic blastema - nephrone

Induction of nephrons

• Interaction between blastema and ureteric bud• Connecting with the branch of ureteral bud• Later development of nephrone

• Distance of glomerulum from the renal medulla is the function of age– Oldest nephrons – juxtamedular

Development of excretory passages

• Urinary bladder– Developed from cranial part of urogenital sinus

– Urachus

– Separation of excretory passages for urine and genital ducts

• Urethra– From medial part of urogenital sinus (at females)

– From medial and caudal part (at males) and glandular plate

Kidney (Ren)

• Nephron

• Intersticium

• Juxtaglomerular apparatus

• Blood supply

• Intrarenal excretory passages for urine

Nepron

• Renal body– Glomerulum– Bowman‘s capsule

• Proximal tubule

• Intermedial tubule

• Distal tubule

Renal body (Malpighi)

• Bowman‘s capsule– Parietal part (squamous epitelium)– Visceral part (podocytes - pedicles)

• Glomerulum – a. afferens a. efferens

– fenestrated capilaries w/o diaphragm

• Filtration barierbasal membrane - collagen type IV and heparan sulfate

• Mesangial cells

Proximal tubule

• Single layered cubic epitelium– Brush border on apical part– Basolateral labyrinth– Abundand mitochondrias

• Resorption of NaCl and water (80-95%)– Na+ into cell pasive, out active

Intermedial tubule

• Thin limb of Henle‘s loop

• Squamous cells, poorly organels– Descendent part permebile for water– Ascendent part inpermeabile for water —

• Juxtamedular nephrons have long HL– countercurrent multiplier - hyperosmotic

medulla

Distal tubule

• Cells are lower than in proximal tubule– No brush border– Basolateral labyrinth

• Reabsorption of natrium, secretion of kalium

• macula densa - chemoreceptors (Cl-)

Juxtaglomerular apparatus

• Parts:– macula densa of distal tubule– granular cells of afferens arteriol (also efferens)– mesangial cells

• Function:– Regulation of blood pressure - renin

Intersticium

• Connected with basal lamina of vessels and tubules

• Cortical vs. medullar• Cells:

• Fibroblast-like cells

• Cells with lipid droplets

• Macrophages, pericytes

• Non-cellular elements• proteoglycans, glycoproteins, interstitial fluid

Blood supply

• aa. interlobares• aa. arcuatae• aa. corticales radiatae• aa. capsulares• aa. afferentes• aa. efferentes

• Peritubular capillaries• vasa recta• vv. arcuatae• vv. corticales radiatae• vv. stellatae• vv. interlobares

Intrarenal excretory passages

• Collecting tubules (Tubulli colligentes)– Single layered cubic epithelium– Round nucleus, light cytoplasm

• Papilar ducts (Ductus pappilares)– Single layered columnar epithelium– Light cytoplasm

• Regulated water reabsorption (ADH)

Slides

Slide U1- kidney HE

Slide U2 - kidney Van Gieson

Kidney HE (U1)Kidney HE (U1)

Kidney Van Gieson (U2)Kidney Van Gieson (U2)

Renal diseases • Diabetic nephropathyDiabetic nephropathy• Acute pyelonephritisAcute pyelonephritis

Excretory passages

• Calices and pelvis

• Ureters

• Urinary bladder

• Urethra

Excretory passages

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

• Smooth muscle (tunica muscularis)

• Adventitia (tunica adventitia)

Renal pelvis and calices

• 2-3 calices in every pelvis

• 2-3-layered transitional epithelium

• Smooth muscle cells spirally

Ureter

• Folded mucosa

• Smooth muscle– Inner layer longitudinal– Outer layer circular

Slides

Slide U3 - ureter HE

Ureter HE (U3)Ureter HE (U3)

Urinary bladder

• Mucosa folded except of area trigonum vesicae

• 3-layered smooth muscle layer – inner plexiform– middle circular ( m. sphincter vesicae)– outer longitudinal

• Part of bladder covered by serosa (peritoneum)

Slides

Slide U4 – urinary bladder HE

Slide U5 – urinary bladder Van Gieson

Urinary bladder HE (U4)Urinary bladder HE (U4)

Urinary bladder Van Gieson (U5)Urinary bladder Van Gieson (U5)

Urethra

• Male urethra have 4 parts:– First two part covered by transitional

epithelium – Other two covered by multilayered sqaumous

epithelium

• Female urethra – Transitional epithelium in intramural part,

continuing with multilayered squamous