Development of Kidney and Urinary Tract

Question 1

urinary and repro system develop from what?

Answer 1

intermediate mesoderm

bilateral strip through all cavities of body (thorax to pelvis)

cloaca - end of gut tube

Question 2

nephrogenic ridge

Answer 2

develop to urinary system

Question 3

gonadal ridge

Answer 3

develop to repro system

Question 4

pronephros

Answer 4

first kidney system formed

• during week 4, then degenerates
• vestigial, nonfunctional

Question 5

mesonephros

Answer 5

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

Question 6

metanephros

Answer 6

third kidney system (permanent)
form week 5, function end of 3rd month

two portions - metanephric blastema and utereric bud

Question 7

metanephric blastema

Answer 7

forms from intermediate mesoderm

-becomes nephron

Question 8

nephron

Answer 8

functional unit of kidney

bowmans capsule, PCT, loop of henle, DCT

Question 9

uteric bud

Answer 9

aka metanephric diverticulum

outgrowth of mesonephric duct
-penetrates metanephric blastema

forms duct system:

• collecting duct
• minor/major calyx
• renal pelvis
• ureter

Question 10

ascent of kidney?

Answer 10

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

Question 11

original blood supply of kidney?

Answer 11

common iliac artery

Question 12

vasculature to kidney as the ascend?

Answer 12

nearby vessels as ascend

• permanent renal arteries are branches of aorta
• caudal branches deteriorate

Question 13

urorectal septum

Answer 13

divides cloaca into anterior urogenital sinus and posterior rectum/anal canal

grows toward cloacal membrane

**proctodeum - invagination of ectoderm

Question 14

urogenital sinus

Answer 14

cranial (vesical) portion
middle (pelvic) portion
caudal (phallic) portion

Question 15

cranial (vesical) portion

Answer 15

forms bladder (not trigone)

• continuous with allantois
• allantois regresses and forms urachus
• urachus forms median umbilical ligament

Question 16

trigone region

Answer 16

from mesonephric duct

Question 17

middle (pelvic) portion

Answer 17

forms urethra in females

forms prostatic and membranous urethra in males

Question 18

caudal (phallic) portion

Answer 18

males only - penile urethra

Question 19

accessory renal arteries

Answer 19

common (25% of population)
-can be arteries or veins

persistence of caudal renal arteries during development

asymptomatic, however can compress ureter and cause hydronephrosis

Question 20

renal hypoplasia

Answer 20

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

Question 21

renal dysplasia

Answer 21

ex./ multicystic dysplastic kidney

and polycystic

present at birth**

Question 22

congenital cystic kidney disease

Answer 22

autosomal recessive or autosomal dominant

cysts are wide dilations of parts of nephrons

Question 23

autosomal recessive CCKD

Answer 23

cysts from collecting duct; renal insufficiency

Question 24

autosomal dominant CCKD

Answer 24

cysts from collecting duct and nephron

Question 25

renal agenesis

Answer 25

uteric bud fails to form and/or induce differentiation of the metanephric blastema
-can be unilateral or bilateral

lack of kidney formation

Question 26

potter sequence

Answer 26

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

Question 27

horseshoe kidney

Answer 27

inferior poles of left and right kidneys fuse in pelvis

ascent blocked by inferior mesenteric artery
-stays in pelvis

usually asymptomatic

Question 28

ectopic (pelvic) kidney

Answer 28

kidneys fail to ascend

-pelvic kidney most common

Question 29

wilm’s tumor

Answer 29

most common malignant tumor of kidneys in children
usually present before age 5
mutation of WT1 gene

Question 30

duplication of ureter

Answer 30

splitting of uteric bud

sometimes can lead to duplication of kidney

Question 31

ectopic ureter

Answer 31

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

Question 32

urachal anomalies

Answer 32

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)

Question 33

exstrophy of bladder

Answer 33

ventral body wall defect; lateral body walls fail to fuse in pelvis

bladder mucosa (inner epithelium) exposed

often presents with epispadias

Question 34

exstrophy of the cloaca

Answer 34

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

Question 35

WAGR syndrome

Answer 35

WT1 and PAX6 mutation

Question 36

Denys-Drash syndrome

Answer 36

mutation of WT1 gene