URINARY SYSTEM

DETAILS OF UROGENITAL DEVELOPMENT

3 week embryo

Intermediate Mesoderm (IM)

Embryonic Origins

DETAILS OF UROGENITAL DEVELOPMENT

3 week embryo

Intermediate Mesoderm (IM)

Embryonic Origins

Urogenital ridge

4 week embryo

DETAILS OF UROGENITAL DEVELOPMENT

3 week embryo

Intermediate Mesoderm (IM)

Embryonic Origins

late 4th week embryo

Nephrogenic cord

Urogenital ridge

DETAILS OF UROGENITAL DEVELOPMENTUrinary System – Nephrogenic Cord

Segmentation

Mesonephros

Metanephros

Pronephros

“Wolffian duct”

DETAILS OF UROGENITAL DEVELOPMENTUrinary System – Division of the Metanephros

5 week embryo

5 weeks

8 weeks

DETAILS OF UROGENITAL DEVELOPMENTUrinary System – Excretory Units

Uriniferous Tubule = Nephron + collecting duct

Nephron= renal corpuscle + excretory tubule

Renal Corpuscle = renal glomerulus + Bowman’s capsule

Bowman’s

Renal Corpuscle Nephron

Uriniferous Tubule

DETAILS OF UROGENITAL DEVELOPMENTUrinary System – Rotation & “Ascent”

of the Kidneys

Variations ofrenal vessels Agenesis

Hypoplasia

Supernumerary kidney

Cystic diseases

Tumors

Duplication of ureter and pelvis

Diverticula

Megaloureter

Calycealcysts

Horseshoekidney

Pelvickidney

Malrotation

Crossed ectopia

Retrocaval andretroarterial

ureter

DETAILS OF UROGENITAL DEVELOPMENTUrinary System – Potential Errors in

Development

•Supernumerary vessels

•Agenesis

•Ectopia

•Ureteric duplication

•Supernumerary kidneys

•Polycystic kidneys

URINARY SYSTEM – COMMON ABNORMALITIES

MULTIPLE RENAL ARTERIES

MULTIPLE RENAL VEINS

URINARY SYSTEM – COMMON ABNORMALITIESSupernumerary Vessels

URINARY SYSTEM – COMMON ABNORMALITIESUnilateral Renal Agenesis

Unilateral pelvic kidney showing the position of the

adrenal gland on the affected side

URINARY SYSTEM – COMMON ABNORMALITIESEctopic Kidney

URINARY SYSTEM – COMMON ABNORMALITIESEctopic Kidney

Horseshoe kidneys showing the position of the inferior mesenteric artery

BW= bladder wallU = ureters

URINARY SYSTEM – COMMON ABNORMALITIESEctopic Kidney

URINARY SYSTEM – COMMON ABNORMALITIESEctopic Kidney – Crossed RenalEctopia

Crossed renal ectopia

URINARY SYSTEM – COMMON ABNORMALITIESPelvic Kidney and Divided Kidney

with Bifid Ureter

URINARY SYSTEM – COMMON ABNORMALITIESMalrotation of kidney and bifid ureter

with supernumerary kidney

URINARY SYSTEM – COMMON ABNORMALITIESSupernumerary kidney resulting from two ureteric buds

Trigone

Seminal vesicle33%

Ejaculatory duct5%Prostatic

utricle10%

Prostaticurethra

47%

Trigone Uterus or cervix5%

Urethra36% Vestibule

34%

Vagina25%

Ductus deferens5%

URINARY SYSTEM – COMMON ABNORMALITIESCommon Sites of Ectopic Ureteric Orifices

Possible sites of ectopic ureteral openings in the vagina, urethra, and vestibule

URINARY SYSTEM – COMMON ABNORMALITIESCommon Sites of Ectopic Ureteric Orifices

URINARY SYSTEM – COMMON ABNORMALITIESPolycystic Kidney

COMPLETING THE EXCRETORY SYSTEMFormation of the Urinary Bladder and Urethra

End of 5th week 7 weeks

8 weeks

COMPLETING THE EXCRETORY SYSTEMFormation of the Urinary Bladder and Urethra

12 weeks

This requires the coordinated behavior of three mesenchymalFolds: The Tourneux fold, and the left and right Rathke folds

COMPLETING THE EXCRETORY SYSTEMSeptation of the Cloaca: Details

Failure of the Tourneux and Rathke folds to form may result in the development of a fistula between the rectum and the bladder

COMPLETING THE EXCRETORY SYSTEMProblems: Septation of the Cloaca

COMPLETING THE EXCRETORY SYSTEMProblems: Septation of the Cloaca

Urachal cysts

Urachal sinus (opening into thebladder and at the umbilicus)

Patent urachus or urachal fistulaconnecting the bladder andumbilicus

COMPLETING THE EXCRETORY SYSTEMProblems: Urachal Anomalies