dev of urnary system Flashcards
What is the origin of the cells forming the kidney and ureters
kidneys and ureters are derived from intermediate mesoderm (IM)- visible during week 3, IM separates from paraxial mesoderm during lateral folding
Urogenital Ridge (urinary and reproductive components share common precursors)
reliant upon Pax 2, 8 and Lim 1
What is the origin of the cells forming the lining of the bladder and urethra
epithelial lining is derived from endoderm (that lines terminal end of hindgut)– cloaca
Wall of bladder and urethra, smooth muscle and CT - from splanchnic mesoderm
What becomes of the mesonephric duct and tubules
the duct and tubules develop within the thoracic and lumbar portions of notochord– mesonephric kidney
duct is mesonephric/wolffian duct
mesonephric duct induces formation of a series of tubules/primitive nephrons–empty into duct, these are mesonephric tubules
metanephric diverticulum and metanephrogenic mesenchyme
metenephric diverticulum/ ureteric bud and metanephrogenic mesenchyme derived from im
become kidney appear during week 5
failure of m. diverticulum to form–> renal agenesis
What is the importance of the ampulla of the metanephric diverticulum, how does it affect the metanephrogenic mesenchyme
Expression of GDNF (glial derived neutrophic factor) and retinoic acid by the mesenchyme induce the formation of the MD, distal MD becomes dilated and is called the AMPULLA– gives signals for development of the nephron
How is the metanephrogenic mesenchyme converted into a nephron
inductive signals from ampulla of md mediate differentiation of a subset of MM into a nephron– segregation, condensation around ampulla, mesenchyme to epithelium transformation forming an epithelial lined vesicle, becomes S shaped tubule
urine begins to form at wk 10- 12
how does the nephron become vascularized
metanephrogenic mesenchyme thats been induced by signals from the MD secretes angiogenic factors (VEGF)`
How do the pelvis ureters and calyces of the kidney form
The pelvis, ureters, calyces and collecting tubules formby branching of the MD
New nephrons are not formed after birth, once ampulla is gone, no more nephron formation
How is the Cloaca subdivided
The cloaca is the dilated terminal portion of the hindgut at the caudal end of the embryo
Your anus+ pee hole
during week 5, a wedge of mesenchyme, the urorectal septum begins to divide to a primary urogenital sinus and anorectal canal
The Cranial portion of the UG sinus becomes the epithelial lining of the UBladder
Trigone
thickend tiangle of internally posterior wall of the bladder
Where the ureters enter and where the urethra leaves
Males the mesonephric ducts open into the forming prostatic urethra
Urachus/allantois
a cyst may occur anywhere along the median umbilical ligament
Renal agenesis
unilateral (usually asymptomatic, 30-40 have associated anomalies, left kidney is most often absent)
Bilateral- incompatible with life, severe oligohydramnios, pulm hypoplasia, potters facial sequence
Renal dysplasia
Cysts and primitive ducts form resulting in a nonfunctional kidney, fatal if bilateral,
renal hypoplasia
kidneys may be small but may be functional
Ectopic kidney
pelvic kidney usually left sided due to failure to ascent, crossed renal ectopia,
Horseshoe kidney
Inferior poles fuse
Polycystic kidney disease
autosomal rececssive type- enlarged kidneys with cortical cyst, reniform shape is maintained, in newborns its usually fatal, in kids (liver HTN CHF), in adults ( liver fibrosis, potal HTN)
Dominant type: bilateral cystic kidneys with large cysts, symptoms in 30s and 40s HTN, berry aneurysms, intestinal diverticulosis
Exstrophy of bladder
common in males, interior bladder is exposed to the exterior, due to weakening of the ventral abdominal wall that causes it ot rupture during development, exposing the inferior of the bladder, associated epispadus in males as well as UG and skeletal anomalies
Posterior urethral valves
Only in males, tissue folds of the posterior urethra mucosa
blocks the urethra
rnal failure in kids
Nephroblastoma
One of two common neoplasms in kids, later in cortex, associated withwt 1 gene located
Hydronephrosis
Distension of the renal pelvis and calices due to obstruction of urinary flow
Urethral agenesis
associated with obstruction of urinary flow from bladder, prune belly
anomalies of the ureter
duplication, primary reflux, ureterocele, megaureter, ectopic ureter
