B5.070 Development of the Urinary System Flashcards
what forms much of the urogenital system
intermediate mesoderm
3 evolutionary stages of kidney development
pronephros- not functional
mesonephros
metanephros
develop in a craniocaudal sequence
describe the mesonephros
functional during embryonic development
mesonephric duct carries urine from mesonephros to fetal cloaca (sewer)…later becomes male reproductive system
paramesonephric duct becomes female reproductive system
ureteric bud
outgrowth from the mesonephric duct
will induce the formation of the metanephric kidney
forms within intermediate mesoderm towards caudal portion of embryo
length of nephrogenesis
continues throughout gestation until about 32-36 weeks
what forms the filtration units of the kidney
ureteric bud induced metanephric blastemal
endoderm (collecting tubules) fused with mesoderm (rest of nephron)
where do kidneys sit in a normal body
about T12
rise from S1 due to differential growth, no muscles pull them up
what is a wilms tumor
nephroblastoma
most common primary renal tumor affecting children and the 4th most common pediatric tumor
account for 9/10 kidney cancers in children
prevalence of wilms tumor
500 cases in US per year
pathophys of wilms tumor
mutation in WT-1 gene
mutations in or loss of WT1 or WT2 gene
tumor suppressor genes found on chromosome 11
hisopath presentation of wilms tumor
tightly packed cells fibrocytic or spindle shaped cells poorly-formed tubules classic triphasic combination of cells: 1. blastemic 2. stromal 3. epithelial
signs and symptoms of wilms tumor
painless, palpable abdominal mass loss of appetite abdominal pain fever nausea and vomiting blood in the urine high BP
diagnosis of wilms tumor
painless abdominal tumor felt by a doctor
US done first followed by CT or MRI
tumor biopsy NOT performed
why is a wilms tumor biopsy not performed
risk of creating fragments of cancer tissue and seeding the abdomen with malignant cells
treatment and prognosis of wilms tumor
surgical removal, plus radiation If tumor has spread
5 year survival is 90%
functions of amniotic fluid
cushioning the embryo
control of the body temperature
prevents adherence of amnion to the embryo
permits symmetrical external growth of the embryo
free movement of embryo
lung development
what is polyhydramnios
condition of having too much amniotic fluid
occurs in 1 in 100 pregnancies
causes of polyhydramnios
GI abnormalities: esophageal atresia, duodenal atresia, tracheoesophageal fistula fatal renal disorders (renal agenesis) Downs and Edwards syndromes anencephaly (impairs swallowing reflex) maternal DM
treatment of polyhydramnios
medications that reduce fluid production are as much ad 90% effective
indomethacin used for idiopathic or maternal DM polyhydramnios- cuts down on renal output of the fetus
if caused by a structural lesion, indomethacin doesn’t solve the issue but can decrease distention
what is amnio-reduction
procedure that can drain excess fluids
amniocentesis
2 types of renal agenesis
unilateral renal agenesis
bilateral renal agenesis
prevalence of unilateral renal agenesis
1/1000 births
slightly more common in males
not major unless other defects are present
effects of unilateral renal agenesis
remaining kidney undergoes slight hypertrophy
sometimes diagnosed during prenatal US, but usually unknown to affected individual
bilateral renal agenesis
1/8000-10000 births
65-80% males
due to oligohydramnios during gestation
incompatible with postnatal life
redundant kidney
more than 2 kidneys
very rare
rotational anomaly
kidney rotates as it ascends
typically unilateral
increases chances of hydronephrosis