Renal embryology Flashcards
what embryo disc layer does the urinary system and genital system develop from?
which develops first?
intermediate mesoderm
urinary system
what is the first thing that the intermediate mesoderm differentiates into?
after that?
after that?
after that?
after that?
urogenital ridge- forms on each side of dorsal aorta—>
portion of ridge forms nephrogenic cord—>
pronephros (becomes rudimentary later)—>
mesonephros- functions briefly in early development
metanephros- permanent kidneys
what intiates cascade leading to formation of definitive kidney?
pronephros
when and where does the pronephros appear?
appears early week 4 in the cervical region
what structure is featured by pronephros and what does it open up into?
pronephric ducts open into the cloaca
when does pronephros degenerate?
what part of it persists?
24-45 days
pronephric ducts persist and are used by mesonephros
when and where does mesonephros appear?
what structures does it include?
bilateral structures that appear l_ate 4th week_ caudal to pronephros
includes mesonephric ducts and tubules (ducts develop first then induce tubules from surrounding mesoderm)
what do mesonephric tubules form?
what is its function?
when does it stop functioning?
renal corpuscles- medial end forms glomerular capsule which wraps around glomerulus (knot of capillaries)
function as interim kidneys from 6-10 weeks and produces a little urine
stops functioniong at 10 weeks
when the renal corpuscles (formed from mesonephric tubules) stop functioning, what do they become in males? females?
males: effect ductules- degenerates at 12 weeks
females: regress
what do the mesonephric ducts induce the formation of?
caudal end induces uteric bud
(also induces tubules as mentioned in another card)
what two things form metanephros?
- uteric bud (from mesonephric duct)
- metanephric blastema (from nephrogenic cord)
when do definitive/functional kidneys form?
what defines them?
9-10 week
have both excretory and collecting portion
what forms renal pelvis?
when the uretic bud elongates and penetrates the blastema (which covers bud)
what does stalk of uretic bud become?
ureter
what forms collecting tubules?
cranial part of bud branches (coming from renal pelvis)
what does the 1st generation of bud branches form (4 of them)?
major calices
what does the 2nd generation of bud branches form (4 of them)?
minor calices
what does the arched part of the collecting tubules do?
what then forms?
induces blastema to form metanephric vesicles—>
vesicles elongate to form metanephric tubules
what do the proximal and distal ends of metanephric tubules form?
proximal: forms glomerular capsule which is invaded by glomeruli
distal: lengthens and differentiates into PCT, DCT, and nephron loop
what does each DCT connect to?
an arches collecting tubule
how are the definitive kidneys placed into the adult position? when does this happen?
what is the kidney now in contact with?
start in pelvis but ascend to abdomen, hilum medially rotates 90 degrees
happens by 9th week
in contact with suprarenal glands
** mesonephros degenerates at this point
what 2 arteries are the first to supply the definitive kidney?
first branch- common iliacs
definiteive renal arteries from abdominal aorta
overview
what portion (collecting or excretory) does uretic bud form?
what adult structures does it give rise to?
collecting portion
gives rise to: ureter, renal pelvis, major and minor calyces, collecting ducts
overview
what portion (collecting or excretory) is metanephric blastema?
what adult structures does it give rise to?
excretory portion
gives rise to: Bowmans capsule, PCT, loop of henle, DCT
what sex is unilateral renal agenesis most common in?
symptoms?
males
usually asymptomatic
what causes bilateral renal agenesis?
associated symptoms?
oligohydramnios
pulmonary hypoplasia (non-viable) and Potter syndrome
what causes duplications in the kidney?
what are the 2 types?
abnormal division of uretic bud
- incomplete division- divided kidney and bifid ureter
- complete- double kidney and bifid or separate ureters
what causes horseshoe kidney?
sx?
fushion of inferior poles and ascent prevented by IMA (?)
asympotamatic
are accessory renal vessels a problem?
(hint: no)
what can happen if they do cause a problem?
no- many adults have them
can obstruct ureter and cause hydronephrosis or if end arteries are damaged can cause ischemia
what causes polycystic kidney disease?
sx?
autosomal recessive mutation of PKHD1
cysts present in both kidneys, renal insufficiency, and pulmonary hypoplasia in some cases
what causes multicystic dysplastic kidney disease?
sx?
cysts are dilations of loop of henle due to abnormal renal development
only one kidney affected in most people
where is the urogenital sinus located?
in the ventral cloaca (along with anorectal canal)
what are the 3 parts of the urogenital sinus?
what separates them?
- vesical part- forms most of bladder
- pelvic part- forms neck of bladder, prostatic urethra (in males), urethra (in females)
- phallic part- forms spongy urethra (in males) and lining of vagina (in females)
all separted by urorectal septum
when does mesonephric duct become incorporated into posterior wall of bladder?
what do they connect to after this?
between weeks 4-6
openings travel inferiorly to connect with pelvic urethra
what is also connecting to the bladder wall at the same time the mesonephric duct is?
what region is formed when these both are connected to bladder?
uretic bud
trigone
what is the epithelium of the bladder derived from?
endoderm (from urogenital sinus?)
what is the submucosa and muscularis of bladder derived from?
splanchnic mesoderm
what is the trigone derived from (layer wise)?
intermediate mesoderm (from mesonephric ducts)
how is median umbilical ligament formed?
starts with allantois (membrane derived from hindgut)—>
it constricts and forms urachus—>
extends from bladder to umbilicus which then forms ligament
what is exstrophy of the bladder (ectopic vesicae)?
when does it arise?
sex most common in?
sx?
defective closure of ventral abdominal wall
arises during body folding in 4th week
males
will have exposure of mucosa of the bladder posterior wall
what is epispadias?
sex common in?
associated sx?
urethral opening on dorsal side of genital tubercle rather than ventral
males
exstrophy of bladder can happen
what is anomaly of urachal cysts?
remnants of urachus epithelium that become large and infected
what is anomaly of urachal sinus?
end of urachus remains open into bladder or umbilicus
what is anomaly of urachal fistula?
entire urachus remains patent and allows escape of urine umbilical orifice
(pee out their belly button. eek)
what does the cortex of the suprarenal gland consist of? what does each layer produce?
(review yay!)
zona glomerulosa: produces mineralocorticoids
zona fasciculata: produces glucocorticoids
zona reticularis: produces sex hormones and estrogen/testosterone related hormones
what does the medulla of suprarenal gland consist of?
chromaffin cells (postganglionic sympathetic neurons) that release NE and Epi
how does the cortex of the suprarenal gland develop?
at week 5, colemic epithelium (somatic mesoderm?) delaminates and enters surrounding mesoderm—>
forms fetal cortical cells—>
becomes definitive cortical cells 2 months after birth—>
cells reorganize and form the zona layers
how does medulla of suprarenal gland form?
neural crest migrate into area and form chromaffin cells
what does the fetal cortical cells secrete to maintain pregnancy?
DHEA which is converted by placenta to estradiol
also secretes ACTH and glucocorticoids
