Development of the Urinary System Flashcards
Where is the urogenital ridge found?
Intermediate mesoderm
How does the pronephros develop?
Appears in week 4
Starts in cervical ridge of embryo
Intermediate mesoderm divides into 6-10 pairs of nephrotomes = tubules
Nephrotomes join into pronephric duct, extending from cervical ridge to cloaca
Regresses by end of week 4
How does the mesonephros develop?
Develops caudally to pronephros
Development of pronephros triggers intermediate mesoderm in thoracolumbar region to form mesonephric tubules
Tubules receive tuft of capillaries from dorsal aorta > blood filtration
Tubules drain into mesonephric duct - continues on from pronephric duct
Most mesonephric tubules regress by end of 2nd month
Mesonephric duct sprouts ureteric bud caudally
How does the metanephros develop?
Forms definitive kidney
Appears in week 5
Functional by ~week 12
Ureteric bud contacts intermediate mesoderm = metanephric blastema
Blastema form metanephric system with 2 parts
- Collecting system
- Excretory system
What is the collecting system of the metanephros?
Derived from ureteric bud Forms - Ureter - Renal pelvis - Major and minor calyces - Collecting tubules Terminates at distal convoluted tubule
What is the excretory system of the metanephros?
Derived from metanephric blastema Metanephric tissue cap collecting tubule > form into excretory tubules Forms - Bowman's capsule - Proximal convoluted tubule - Loop of Henle - Distal convoluted tubule
What is the course of the definitive kidney during its development?
Develops in pelvic region
Migrates up into abdomen
When is the cloaca divided into two parts by the urorectal septum?
Weeks 4-7
What are the two parts of the divided cloaca?
Urogenital sinus, anteriorly
Anal canal, posteriorly
Into what does the urogenital sinus divide?
Bladder
Urethra
Some of reproductive tract in females
What is the allantois?
Initially drains bladder
Obliterates during development
Becomes urachus
What is the remnant of the urachus in adults?
Median umbilical ligament
What forms the trigone of the bladder?
Absorption of developing bladder of mesonephric/Wolffian ducts
What structure in the adult male do the Wolffian ducts eventually form?
Ejaculatory ducts
