Renal Embryology Flashcards
What portion of the embryo do the kidneys come from
Intermediate mesoderm
Where is the intermediate mesoderm located
Immediately lateral to the somites
What portion of the kidneys develops first
Urinary system
Where does the urogenital ridge form
On each side of the dorsal aorta
Where does the nephrogenic cord form from
Urogenital ridge
What does the nephrogenic cord give rise to
Pronephros, mesonephros, metanephros
What portion of the nephrogenic cord forms the permanent kidneys
Metanephros
What is the general order of development of the kidneys
Urogenital ridge —> neprhogenic cord —> pronephros —> mesonephros —> metanephros
When does the pronephros form
Early in the 4th week in the cervical region
What does the cloaca handle
Gives off urinary and GI waste
What does the pronephric ducts dump into the
Cloaca
What does the cloaca form in mature adults
Bladder
When does the pronephros degenerate
24-25 days
What initiates the cascade leading to the formation of the kidney
Pronephros
When does the mesonephros appear
Late in the 4th week and below the pronephros
Do the mesonephric ducts or tubules develop first
Ducts
What induces the tubules to form from the intermediate mesoderm
Mesonephric ducts
Mesonephric tubules form the what in mature kidneys
Glomerular capsule
When do the mesonephric tubules function as interim kidneys
6-10 weeks
When do the mesonephric tubules stop functioning? When do they degenerate
10 weeks in females; forms efferent ductules in males
12 weeks
When do the metanephros arise
5 weeks
What does the caudal end of each mesonephric duct induce
Ureteric bud
What are the 2 parts of the metanephros
Ureteric bud and metanephric blastema
Where does the metanephric blastema grow from
Nephrogenic cord
How does the metanephros form
Reciprocal induction which is essential to proper development
When does the functional and definitive kidney form
9-10th week
What does the ureteric bud form
Penetrates the blastema and forms the renal pelvis
What does the stalk of the ureteric bud become
Ureters
What do the first 4 generations of the collecting tubules form? Next 4?
Major calices; minor calices
What does the arched collecting tubule induce the metanephrogenic blastema to form
Metanephric vesicles
What do the metanephric vesicles form
Metanephric tubules
The upper metanephric tubules differentiate into
PCT, DCT, and loop of henle
Where do the permanent kidneys lie
In pelvis and move into the abdomen
What direction is the hilum previous to its mature location
Faces the ventral and rotates 90 degrees
When are the kidneys in their adult position
9th week
What supplies the early kidneys? Adult kldneys?
Common iliac A; renal A from abdominal aorta
What is a common cause suspected with unilateral renal agenensis
Infants with 1 umbilical A; more frequent in males
What is a cause of bilateral renal agenesis
Oligohydramnios and often concurrent with potter syndrome
What is potter syndrome
Associated with low amniotic fluid and causes face deformation and clubbed legs
What is incomplete division of kidney
Divided kidney and bifid ureter
What is a complete division
Double kidney and bifid ureter or separate urerters
What is horseshoe kidney
Fusion of inferior poles and its ascent to mature position by inferior mesenteric A
Why is horseshoe kidney dangerous
Lower back injuries can cause kidney damage
What are the issues with accessory renal vessels
Occurs in 25% of adult kidneys
2x common as accessory veins
What do obstructions in accessory renal vessels result in
Hydronephrosis
What are the parts of the urogenital sinus
Vesical part - forms most of the urinary bladder
Pelvic part - forms neck of bladder, prostatic urethra (m), and urethra (f)
Phallic part - forms spongy urethra (m) and lining of vaginal vestibule (f)
What layer does the bladder form from
Endoderm
What forms the trigone
Mesonephric duct
What does the bladder develop from
Vesical part of the urogenital sinus
What does the epithelium of the bladder form from
Endoderm (urogenital sinus)
Where does the submucosa and muscularis form from
Splanchnic mesoderm
What does the trigone form from
Intermediate mesoderm (mesonephric ducts)
Bladder is continuous with what
Allantois
What does the allantois constrict and form
Urachus —> medial umbilical ligament in adults
When does exstrophy of the bladder arise
4th week during body folding
What is exstrophy of the bladder
Defective closure of ventral abdominal wall
Exposure of mucosa of the posterior wall of bladder
What is epispadias
Urethral opening is on the dorsum of the genital tubercle rather than on its ventral side
What does epispadias occur frequently with
Exstrophy of the bladder
What are the urachal anomalies
Urachal cysts - cysts can become infected and enlarged
Urachal sinus - end of the urachus remains open into the bladder
Urachal fistula - entire urachus remains patent and allows urine to come out of the umbilicus
What re the symptoms of urachal anomalies
Leakage from umbilicus or UTI
What is the origin of chromaffin cells
Neural crest cells
When does the suprarenal gland form
5th week
What is the origin of the suprarenal gland
Intermediate mesoderm
When does the fetal cortex regress
2nd month
What do cortical cells of suprarenal gland reorganize into
Zona glomerulosa, zona fasiculata, zona reticularis
What does the fetal cortex secrete
DHEA (dehydroepiandrosterone) converted by placenta to estradiol
This is essential for maintaining pregnancy and also secretes ACTH and glucocorticoids
What 2 things communicating are responsible for the development of the kidney
Metanephric blastema and metanephric tubules
What does the ureteric bud form in adults
Ureter, renal pelvis, major and minor calyces, collecting ducts
What does the metanephric blatema form in adults
Bowman’s capsule, PCT, DCT, LoH
What causes duplications in the kidney
Abnormal division of ureteric bud
What is defective in polycystic kidney disease
Autosomal recessive mutation of PKHD1
What do you find physically in polycystic kidney disease
Cysts present in both kidneys and renal insufficiency
Often found with pulmonary hypoplasia (oligohydramnios)
In multicystic kidney disease what are the cysts likely to have formed from
Dilations of LoH
What is the big difference between polycystic kidney disease and multicystic dysplastic kidney disease
PKD = both kidneys affected
MDKD = one kidney affected
What does the bladder mainly develop from
Vesical part of urogenital sinus
What does the bladder epithelium come from
Endoderm (urogenital sinus)
What does the bladder submucosa and muscularis form from
Splanchnic mesoderm
What does the trigone form from
Intermediate mesoderm (mesonephric ducts)
What does the zona glomerulosa produce
Mineralocorticoids
What does the zona fasiculata produce
Glucocorticoids
What does the zona reticularis produce
Sex hormones
What does the fetal cortex secrete and what does the placenta convert it to
DHEA; estradiol
