Urinary system (embryology) Flashcards
What gives rise to most organs of both the urinary and genital systems?
Intermediate mesoderm (except urogenital sinus)
What are the derivatives of the urogenital sinus?
Urinary bladder, urethra and associated glands
What 3 kidney systems are formed in a cranial-caudal sequence?
- Pronephros
- Mesonephros
- Metanephros
Pronephros
Tubules degenerate
Duct remains and empties into the cloaca (nonfunctional)
Mesonephros
Mesonephric tubules and mesonephric duct
Functional kidney in adult fish and amphibian
Functional transitory in mammals
What does the pronephric duct become?
Mesonephric duct
Remains and forms the male duct system (epididymus, ductus deferens and seminal vesicle)
Filtrate transported
Mesonephric tubules
Most degenerates
Few remain and become efferent ductules
Blood transported
Metanephros
Functional kidney in adult reptiles, birds and mammals
Originates from metanephric bud and metanephric blastemal
Metanephric bud (ureter bud)
Grows out of mesonephric duct near the cloaca (distal end)
Forms ureter, renal pelvis and collecting ducts
Metanephric blastemal
Condensed mesenchymal tissue in front of ureter bud
Forms the nephron: renal corpuscle, PT, Henle’s loop and DT
Cloaca
Common chamber for digestive, urinary and genital systems in the mammalian embryo
Lined by endoderm
Urorectal spetum
Divides cloaca into rectum and anal canal dorsally and urogenital sinus ventrally
Urogenital sinus
divided into vesicular, urethral, pelvic and phallic parts
What does the vesicular part of the urogenital sinus become?
Urinary bladder which cranially continues as urachus (intraembryonic/ distal part of the allantoid)
Where do the mesonephric duct and ureter open initially?
Dorsal wall of the bladder
What happens with differential growth of the dorsal wall of the bladder?
Ureter opening moved cranially creating a trigone region that anchors the ureter to the bladder and urethra
Mesonephric duct opens caudally
Pelvic urethra in males
Continuous with the urinary bladder
Penile urethra incorporated into the penis
Bulbourethral gland develops from this part of the urethra
Where does the prostate gland develop?
from Urethral epithelium
All derivatives of the urogenital sinus are _______________
Endodermal
Hydronephrosis
Results from blockage in the ureter
Embryological origin: blockage in the collecting system leadint to fluid-filled cysts
What does a double ureter lead to?
Ectopic ureter or ureterocele
Incontinence in females
If ureter opens proximal to the urethralis muscle
Patent urachas
Results form the failure of allantoic stalks to close at birth
