Development of Kidney and Urinary Tract Flashcards
urinary and repro system develop from what?
intermediate mesoderm
bilateral strip through all cavities of body (thorax to pelvis)
cloaca - end of gut tube
nephrogenic ridge
develop to urinary system
gonadal ridge
develop to repro system
pronephros
first kidney system formed
- during week 4, then degenerates
- vestigial, nonfunctional
mesonephros
forms in thoracic and upper lumbar regions
- second kidney system formed
- intermin kidney until about month 3
mesonephric tubules drain to mesonephric (wolffian) duct, which drains to cloaca
metanephros
third kidney system (permanent)
form week 5, function end of 3rd month
two portions - metanephric blastema and utereric bud
metanephric blastema
forms from intermediate mesoderm
-becomes nephron
nephron
functional unit of kidney
bowmans capsule, PCT, loop of henle, DCT
uteric bud
aka metanephric diverticulum
outgrowth of mesonephric duct
-penetrates metanephric blastema
forms duct system:
- collecting duct
- minor/major calyx
- renal pelvis
- ureter
ascent of kidney?
forms in pelvis, ascends to abdomen by week 9
rotate 90 medially as ascend
starts week 6
also, fetal kidney is lobulated
-at birth - smooth
original blood supply of kidney?
common iliac artery
vasculature to kidney as the ascend?
nearby vessels as ascend
- permanent renal arteries are branches of aorta
- caudal branches deteriorate
urorectal septum
divides cloaca into anterior urogenital sinus and posterior rectum/anal canal
grows toward cloacal membrane
**proctodeum - invagination of ectoderm
urogenital sinus
cranial (vesical) portion
middle (pelvic) portion
caudal (phallic) portion
cranial (vesical) portion
forms bladder (not trigone)
- continuous with allantois
- allantois regresses and forms urachus
- urachus forms median umbilical ligament
trigone region
from mesonephric duct
middle (pelvic) portion
forms urethra in females
forms prostatic and membranous urethra in males
caudal (phallic) portion
males only - penile urethra
accessory renal arteries
common (25% of population)
-can be arteries or veins
persistence of caudal renal arteries during development
asymptomatic, however can compress ureter and cause hydronephrosis
renal hypoplasia
inadequate branching of uteric bud and lack of differentiation of nephron
functional nephrons are present, just very few
persistent fetal lobulation type of renal hypoplasia
problem if it is bilateral
renal dysplasia
ex./ multicystic dysplastic kidney
and polycystic
present at birth**
congenital cystic kidney disease
autosomal recessive or autosomal dominant
cysts are wide dilations of parts of nephrons
autosomal recessive CCKD
cysts from collecting duct; renal insufficiency
autosomal dominant CCKD
cysts from collecting duct and nephron
renal agenesis
uteric bud fails to form and/or induce differentiation of the metanephric blastema
-can be unilateral or bilateral
lack of kidney formation
potter sequence
bilateral renal agenesis
-oligohydramnios due to no urine production
secondary symptoms:
potter facies - broad flat nose, wide set eyes, low set ears, micrognathia, club foot
lungs and limbs - amniotic fluid
horseshoe kidney
inferior poles of left and right kidneys fuse in pelvis
ascent blocked by inferior mesenteric artery
-stays in pelvis
usually asymptomatic
ectopic (pelvic) kidney
kidneys fail to ascend
-pelvic kidney most common
wilm’s tumor
most common malignant tumor of kidneys in children
usually present before age 5
mutation of WT1 gene
duplication of ureter
splitting of uteric bud
sometimes can lead to duplication of kidney
ectopic ureter
two utereric buds form
- one ureter has normal opening
- other opens into abnormal site on bladder, urethra, vestibule, or vagina and is usually enlarged
lower is normal
urachal anomalies
occurs when lumen of allantois persists
urachal fistula - entire lumen remains open, urine may leak from umbilicus
fistula - abnormal opening
urachal sinus urachal cyst (fluid filled)
exstrophy of bladder
ventral body wall defect; lateral body walls fail to fuse in pelvis
bladder mucosa (inner epithelium) exposed
often presents with epispadias
exstrophy of the cloaca
ventral body wall defect; lateral body walls fail to fuse
more severe than exstrophy of bladder
- bladder mucosa exposed
- urorectal spetum is also deficient, thus exposure of rectum also present
inperforate anus
often present with epispadias
WAGR syndrome
WT1 and PAX6 mutation
Denys-Drash syndrome
mutation of WT1 gene
