Development Of The urinary Tract Flashcards
What’s the 1st kidney system to develop and what’s its function?
The pronephros
Never functions but the pronephric duct extends from the cervical region to the cloaca and drives the development of the next stage
4th week
What’s the urogenital ridge made from and what does it give rise to?
Made from intermediated mesoderm
Gives rise to the embryonic kidney and gonad
When and What’s the second kidney system to develop and what’s it function?
The mesonephros/ embryonic kidney
Mesonephric tubules (develop caudal to the pronephric region) + mesonephric duct = embryonic kidney
No water conserving function
Mesonephric duct (-> ureter and trigone of bladder and epididymis, vas deferens and seminal vesicle in men) sprouts the ureteric bud
6-10th week
What’s the function of the ureteric bud?
Induces development of the definitive kidney by driving change in undeveloped intermediate mesoderm adjacent (the metanephric blastema)
Forms the collecting system and calyxs of the kidney and connects to the urogenital sinus to eventually become the ureter
What’s the excretory component of the kidneys derived from?
The metanephric intermediate mesoderm under the influence of the ureteric bud
Describe the ascent of the kidney
Metanephric kidney first appears in the pelvic region -> caudal to cranial shift crossing the arterial fork
Why are accessory renal arteries so common?
25% of the population
New renal arteries develop as kidneys move up, old ones may not get absorbed and remain
End arteries
What can occur if ureteric bud fails to interact with intermediate mesoderm?
Renal agenesis
If bilateral = fatal
what does Duplication of ureteric buds lead to?
Ectopic ureters which open in the wrong place e.g. vagina, urethra surpass the sphincter and detrusor muscle -> urinary incontinence
Sometimes kidney may also get an extra lobe or even duplex of a whole kidney
What’s a pelvic kidney?
A kidney that fails to ascend
What’s a horseshoe kidney?
Fusion of the kidneys at the caudal end - usually asymptomatic
What three systems develop from the hindgut? What does the hindgut initially end in?
Urinary
Genital
Gastro-intestinal
Ends with cloaca which is closed to the outside by the cloacal membrane
How does the urogenital sinus get created?
Created from the hindgut by the urorectal septum which separates the hindgut into the urogenital sinus and the anorectal canal in 8th week
What does the urogenital sinus develop into and connect with?
Superior part connects to the umbilicus via the urachus (remnant of the allantois 5-7th week)
Majority differentiates to form the urinary bladder
Inferior part develops into the urethra
What’s the main differences in the development of the urogenital sinus and the mesonephric ducts in men and women?
Both: mesonephric ducts reach urogenital sinus
Ureteric bud sprouts from MD
ugS begins to expand
Females: md regresses and ureteric buds open into UGS. Urethra forms from UGS.
Makes: smooth musculature appears on MD, ureteric buds and MdS make openings into UgS. Prostate and prostatic urethra formed from ugs. Vas deferens, epididymis and seminal vesicle formed from MDs.
