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 DEVELOPMENT Urinary System – Nephrogenic Cord Segmentation Mesonephros Metanephros Pronephros “Wolffian duct”

DETAILS OF UROGENITAL DEVELOPMENT Urinary System – Division of the Metanephros 5 week embryo 5 weeks 8 weeks

DETAILS OF UROGENITAL DEVELOPMENT Urinary 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 DEVELOPMENT Urinary System – Rotation & “Ascent” of the Kidneys

Variations of renal vessels Agenesis Hypoplasia Supernumerary kidney Cystic diseases Tumors Duplication of ureter and pelvis Diverticula Megaloureter Calyceal cysts Horseshoe kidney Pelvic kidney Malrotation Crossed ectopia Retrocaval and retroarterial ureter DETAILS OF UROGENITAL DEVELOPMENT Urinary 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 ABNORMALITIES Supernumerary Vessels

URINARY SYSTEM – COMMON ABNORMALITIES Unilateral Renal Agenesis

Unilateral pelvic kidney showing the position of the adrenal gland on the affected side URINARY SYSTEM – COMMON ABNORMALITIES Ectopic Kidney

URINARY SYSTEM – COMMON ABNORMALITIES Ectopic Kidney

Horseshoe kidneys showing the position of the inferior mesenteric artery BW= bladder wall U = ureters URINARY SYSTEM – COMMON ABNORMALITIES Ectopic Kidney

URINARY SYSTEM – COMMON ABNORMALITIES Ectopic Kidney – Crossed Renal Ectopia Crossed renal ectopia

URINARY SYSTEM – COMMON ABNORMALITIES Pelvic Kidney and Divided Kidney with Bifid Ureter

URINARY SYSTEM – COMMON ABNORMALITIES Malrotation of kidney and bifid ureter with supernumerary kidney

URINARY SYSTEM – COMMON ABNORMALITIES Supernumerary kidney resulting from two ureteric buds

Trigone Seminal vesicle 33% Ejaculatory duct 5% Prostatic utricle 10% Prostatic urethra 47% Trigone Uterus or cervix 5% Urethra 36% Vestibule 34% Vagina 25% Ductus deferens 5% URINARY SYSTEM – COMMON ABNORMALITIES Common Sites of Ectopic Ureteric Orifices

Possible sites of ectopic ureteral openings in the vagina, urethra, and vestibule URINARY SYSTEM – COMMON ABNORMALITIES Common Sites of Ectopic Ureteric Orifices

URINARY SYSTEM – COMMON ABNORMALITIES Polycystic Kidney

COMPLETING THE EXCRETORY SYSTEM Formation of the Urinary Bladder and Urethra End of 5 th week 7 weeks 8 weeks

COMPLETING THE EXCRETORY SYSTEM Formation of the Urinary Bladder and Urethra 12 weeks

This requires the coordinated behavior of three mesenchymal Folds: The Tourneux fold, and the left and right Rathke folds COMPLETING THE EXCRETORY SYSTEM Septation 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 SYSTEM Problems: Septation of the Cloaca

COMPLETING THE EXCRETORY SYSTEM Problems: Septation of the Cloaca

Urachal cysts Urachal sinus (opening into the bladder and at the umbilicus) Patent urachus or urachal fistula connecting the bladder and umbilicus COMPLETING THE EXCRETORY SYSTEM Problems: Urachal Anomalies