15: Renal Embryology Flashcards
Where is intermediate mesoderm located?
Immediately lateral to each somite
Ascent of the kidneys
Kidneys lie within pelvis, and gradually “ascend” into pelvis - dont actually move, but embryo lengthens
When are kidneys in adult positioning by?
9th week
Initial vs definitive blood supply to kidneys
Initial: from common iliacs
Definitive: abdominal aorta
Issues with having accessory renal vessels
Can obstruct ureter and lead to hydronephrosis
Which is more common, accessory renal arteries or veins?
Arteries (found in 25% of adults)
Structures formed from the ureteric bud vs metanephrines blastema
Ureteric bud -> ureter, renal pelvis, calyces, CDs
Metanephrines blastema -> Bowman’s capsule, prox tubule -> distal tubule
unilateral renal agenesis S/S and when to suspect it
Typically asymptomatic, suspected in infants with 1 umbilical artery
Bilateral renal agenesis
Results in oligohydramnios and is non-viable due to pulmonary hypoplasia
Incomplete and complete divisions in ureter duplications
Incomplete division -> divided kidney and bifid ureter
Complete division -> double kidney and bifid ureter or separate ureters
How does horseshoe kidney form?
Fusion of inferior poles to form isthmus between kidneys
Symptoms of horseshoe kidney
Typically asymptomatic but can be problematic in conditions like pregnancy
Why is the horseshoe kidney more inferiorly positioned?
Ascent is prevented by IMA
ARPKD: autosomal recessive polycystic kidney disease presentation
S/S present before/shortly after birth, cysts present in both kidneys, renal insufficiency, 25% associated with pulmonary hypoplasia
Multicystic dysplastic kidney disease
Multiple non-communicating cysts of varying size on the kidney, likely due to dilations of the loop of Henle
What does the vesical part of the urogenital sinus form?
Urinary bladder
What forms bladder epithelium?
Endoderm
What forms bladder submucosa and muscularis?
Splanchnic mesoderm
What forms the bladder trigone area?
Intermediate mesoderm
What 2 things does the allantois form in the bladder?
Urachus, median umbilical ligament
Exstrophy of the bladder
Defective closure of ventral abdominal wall -> exposure of mucosa of the posterior wall of the bladder
When does exstrophy of the bladder occur?
During body folding, 4th week
Urachal cyst
Remnants of epithelial lining of urachus that can become infected and enlarged
Urachal sinus
End of the urachus remains open into the bladder or umbilicus
Urachal fistula
Entire urachus remains patent and allows urine to escape from umbilical orifice
Three urachal anomalies
Urachal cysts, urachal sinus, urachal fistula
