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Paediatric Surgery
Embryology of the Urinary Tract
Built from Puri — Pediatric Surgery and Pediatric Urology
What’s inside
9 sections · 63 slides
Overview
- Why an embryology of the urinary tract matters
- Roadmap of this deck
Early Embryonic Events
From one cell to the three tissue layers
- From fertilisation to the blastocyst
- Implantation and the bilaminar disc
- Gastrulation: making three germ layers
- The mesoderm splits into three columns
- Three columns of mesoderm beside the streak
- Folding turns the flat disc into a tube
- Head-and-tail folding encloses the gut tube
- The cloaca, allantois and urogenital folds
- Allantois, cloaca and the paired urogenital folds
- Reproduction is planned early: primordial germ cells
Renal Development
Three kidneys in sequence — only the last one stays
- The kidney is built in three tries
- Pronephros, mesonephros and metanephros in sequence
- Pronephros and mesonephros
- Wolffian (mesonephric) ducts draining the mesonephros
- The metanephros: the ureteric bud meets the blastema
- Branching builds the drainage and the filters
- The kidney climbs and turns
- Fetal urine and amniotic fluid
- The genetics behind CAKUT
- Three master genes of renal development
Ureteric Bud Anomalies
Where the bud starts decides how the kidney turns out
- Renal agenesis and dysplasia
- Where the bud starts predicts reflux or ectopia
- Weigert-Meyer duplex law
- Duplex kidney: two buds, two moieties
- Incomplete versus complete duplex systems
- Position, rotation and fusion errors
Bladder, Trigone and Lower Ureter
Dividing the shared chamber and plumbing the ureters in
- Splitting the cloaca into front and back
- Forming the bladder and the urachus
- Building the trigone
- Hollowing out the ureter
Anomalies of Cloacal Partitioning
When the front wall and the septum fail
- Bladder exstrophy
- Epispadias
- Cloacal exstrophy and cloacal anomalies
- Anomalies of the trigone
Genital and Reproductive Tract
One indifferent start, two divergent paths
- The indifferent gonad and two duct systems
- Male and female genital tract development
- Male internal genitalia: two hormones, two jobs
- Wolffian duct derivatives and the prostate
- Testicular descent in two phases
- Wolffian duct derivatives and testicular descent
- Female internal genitalia: the default path
- Mullerian fusion anomalies
External Genitalia
A shared blueprint and its common anomalies
- The indifferent external genitalia
- Common origin of male and female external genitalia
- Male external genitalia
- Female external genitalia
- Hypospadias
- Congenital adrenal hyperplasia (CAH)
Summary
The through-lines to remember
- Same tissue, two systems
- Key takeaways
- References
- Pediatric Surgery and Pediatric Urology