1. DEVELOPMENT OF KIDNEY,URETER & BLADDER
Lecture by Prof. Dr. Ansari
(for MBBS semester I students only)
Sunday, April 23, 2017.

2. Objectives
The three generations of kidney development, pronephros, mesonephros & metanephros.
The ureter development and their developmental anomalies.
The urinary bladder development and anomalies.
The kidney developmental anomalies.

4. The first generation kidney develops during 4th week of development from intermediate mesoderm/urogenital ridge

5. Pronephros are rudimentary, nonfunctional & regresses completely

6. The mesonephros
The mesonephros is functional for short period & remains as the mesonephric duct/Wolffian duct.
Urine formation begins between 11 –12 weeks &
Continues throughout fetal life.

7. The metanephric blastema (intermediate mesoderm)
The ureteric bud grows out from the mesonephric duct and induces changes into the metanephric blastema.
The metanephric blastema differentiates into the functional units of the kidneys - the nephrons (approximately 1-2 million per kidney).
The mesonephric duct drains into the allantois close to the cloaca.

8. The ureteric bud
From the ureteric bud develops the collecting duct system, including the collecting tubules which link with the nephrons, the major and minor calyces, the renal pelvis, and the ureter.

9. Saggittal section of a 5-week-old embryo
1.Nephrogenic cord
2. Mesonephric duct
1+2. Mesonephros
4 Cloaca
5 Atrophied pronephros
7Allontois
9 Ureteric bud

10. The metanephros develops from the intermediate mesoderm (5) of the sacral region:

11. The ‘ascent’ of the kidneys
Each metanephric kidney 'ascends' from the pelvic region, where it originates, to its final position on the posterior wall of the abdomen.
It reaches T12 – L3 vertebral level by 9th week of intra-uterine life.

13. Formation of urogenital sinus
Urogenital ridge
Genital ridge
Mesonephric duct
Mesonephros
Gonad
Metanephric tissue
Ureter
Cloacal membrane
Cloaca
Allontois
Urorectal septum
Tail

14. The uro-genital sinus may be divided into three component parts
The first of these is the cranial portion which is continuous with the allantois and forms the bladder proper.
The pelvic part of the sinus forms the prostatic urethra in the male and the membranous urethra and part of the vagina in females.
Thirdly, the caudal portion, or definitive uro-genital sinus, forms the penile urethra in males and the vestibule in females.

15. (Allontois +Bladder)
(Prostatic urethra+ membranous
Urethra & part of vagina)
(Penile urethra and part of vestibule)
Urogenital sinus

16. Urinary bladder sources of development
1. Urogenital sinus
2.Allontois
3. Endoderm
4. Trigone from metanephric ducts
5. Connective tissue + Muscles from Splanchnic mesoderm
6. Allontois will form Urachus and later median umbilical ligament.

17. Pelvic & Pancake kidney

18. Horse shoe kidney

19. Polycystic kidney (Due to non communication Between ureteric bud &
Metanephros)

20. Polycystic kidney section

21. Agenesis of kidney
1;1000 live births incidence of renal agenesis

22. Renal agenesis

23. Double
Ureters are
Developmental defect
As a result of earlier
Bifurcation of ureteric
bud

24. Bilateral doubling of ureters

25. Double kidney

26. Urachal fistula (4)
It is a congenital defect due to persistence of allontoic canal/patent urachus.
It opens at the umbilicus.
Urine dribbling out from the umbilicus.

27. Adult derivatives of embryonic kidney
1. Ureteric bud…….Ureter, renal pelvis, major/minor calyces, & collecting tubules.
2. Metanephric mesoderm….Renal glomeruli + capillaries + Bowman’s capsule + PCT + loops of Henle +DCT.
3. Mesonephric duct derivatives are epidydimis, vas deferens, trigone of bladder, ureter.

28. Exstrophy of bladder
The urinary bladder is exposed out side on the anterior abdominal wall.
It is due to non development of infra umbilical part of abdominal wall.