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