Renal Embryology Flashcards
Nephrogenic cord gives rise to (2)
Nephrons and ducts.
Pronephros overview
Appears in week 4 and degenerates shortly after.
Rudimentary - no function.
Has a pronephric duct and pronephric tubule.
Mesonephros overview
Appears late week 4 and is functional until week 11.
Has a mesonephric duct and mesonephric tubule.
Mesonephric duct and tubule give rise to:
Male genitalia.
Metanephros overview
Begins to develop in week 5.
Is functional and definitive.
Contains a ureteric bud and metanephrogenic blastema (mass) in the pelvis.
Metanephrogenic blastema and ureteric bud give rise to:
The nephron and collecting system.
Glomerulus is from:
Dorsal aorta
Bowman’s capsule and mesonephric tubules are from:
IM
How does the mesonephric duct induce nephrons in adjacent nephrogenic cords?
The MD and MV undergo reciprocal signaling which causes the MV to become the MT and meet with the MD. The MT continues to elongate and form around the glomerulus.
Ureteric bud (metanephric duct) is an:
Outgrowth from mesonephric duct.
Metanephric duct is derived from:
Nephrogenic cord.
Ureteric bud gives rise to (5):
Ureter Pelvis Major calyces Minor calyces Collecting tubules All from IM.
Metanephric blastema gives rise to (5):
Renal vesicles Bowman's capsule Proximal CT Distal CT Loop of Henle All from IM.
Development of the collecting system
Ureteric bud contacts the metanephroc blastema and gives rise to the renal pelvis.
Ureteric bud bifurcates and branches and coalesces to form major, then minor calyces.
Development of the nephron of the metanephros
Nephron originates as a vesicle within the blastemic mass surrounding the collecting duct.
After signaling, the vesicle elongates into a tube and the glomerulus forms at one end and the proximal end forms the proximal CT, Loop of Henle, and distal CT.
Unilater renal agenesis
More common in males.
Usually asymptomatic due to one kidney becoming hypertrophied.
Suspected in infants with one umbilical a.
BL renal agenesis
Associated w/ oligohydramnios (and therefore lung problems).
20% of Potter sequence pts have renal agenesis.
Renal agenesis is due to:
Ureteric bud and/or metanephric blastema did not develop properly.
Duplex kidney
2 ureters at each kidney.
Abnormal division of the ureteric bud.
Asymptomatic.
Kidneys receive blood from:
Nearby arteries. Often the iliac as.
Ascent of the kidney
They are at adult position at week 9.
Due to caudal growth of the embryo.
Rotate 90 degrees during ascent.
Pelvic kidneys, horseshoe kidneys do not ascend due to:
Being blocked by vasculature.
Autosomal recessive polycystic kidney disease
Mutation of PKDH1 gene.
Both kidneys contain many small cysts.
Renal insufficiency.
25% associated with pulmonary hypoplasia.
Multicystic dyplastic kidney disease
Abn development of the renal system.
Usually only one kidney affected.
Fewer cysts than ARPKD.
Cysts are thought to be due to wide dilations of the Loop of Henle.
Ureter is from (2):
Mesonephric and metanephric ducts.
Bladder is from:
Hindgut endoderm, except for trigone which is mesoderm.
In the adult, the ureter is only from:
Metanephric duct.
Urorectal septum
Separates the urogenital system from the rectum at the cloaca.
Development of the median umbilical ligament in adults
Allantois –> urachus –> median umbilical ligament.
3 regions of the urogenital sinus
Vesicle part (bladder) Pelvis part (urethra (f) or prostatic and membranous urethra (m)) Phallic (lining of vaginal vestibule (f) or spongy urethra (m))
Urachal fistula
Opening from bladder to naval.
Urine can leak through the naval.
Urachal sinus
Deep invagination of the naval. Small median umbilical ligament can be ruptured and can cause a urachal fistula, but is rare.
Exstrophy of the bladder
Arises in week 4 from body folding.
Bladder exists outside of the abdomen.
Epispadias
Small opening on the dorsal side of the penis. Urine can leak.
Improper location of genital tubercles caudal to cloacal membrane.
Adrenal medulla is from:
NC (Chromaffin cells).
Adrenal capsule is from:
Mesonephric mesoderm (IM)
Adrenal cortex is from:
Somatic mesoderm.
First and second cellular wave give rise to:
1st - fetal cortex
2nd - adult cortex
Fetal cortex produces
Pituitary ACTH, glucocorticoids, estrogen precursors.
