Kidney development; 3.31 Flashcards
What does the urogenital ridge develop from?
Intermediate mesoderm
What happens during the pronephric phase?
Pronephric duct grows towards the cloaca (genitalia)…pronephric duct later degenerates
What does the pronephric duct become during the mesonephric phase?
Mesonephric or Wolffian duct
What do the mesonephric tubules become in males?
Mesonephric tubules become the efferent ductules of the testes (connect the testis to the ductus deferens)
What does the mesonephric duct become in males?
Ductus (vas) deferens ad ureteric bud (metanephric diverticulum)
What does the mesonephric duct become in females?
Ureteric bud only
What does the ureteric bud (metanephrogenic diverticulum) grow into?
Ureteric bud grows into the intermediate mesoderm (metanephrogenic mesoderm/blastema)
What does the ureteric bud initiate?
Metanephric diverticulum initiates formation of the definitive/permanent kidney (metanephros)
What does the metanephric kidney consist of?
Ureter
Renal pelvis
Major/minor calyces
Collecting duct
What do the nephrons derive from?
Metanephric tubules (from metanephric mesoderm)
What are uriniferous tubules?
Nephrons and collecting ducts
Know that nephrons and collecting ducts develop from different sources
Collecting tubes = metanephric diverticulum
Neprons = metanephric tubules
What is the original supply to the metanephric kidney?
The common iliac…then the body grows caudally and the kidneys “rise”
What causes renal agenesis?
Failure of ureteric bud and metanephric mesoderm to interact
Which kidney more commonly does not form? Which gender is more likely to be born with only one kidney?
The left kidney is more likely to NOT develop
Renal agenesis is more common in males
When should renal agenesis be suspected?
In infants with a single umbilical artery
What causes duplicated or branched ureters and supernumerary kidney?
Bifurcation of ureteric bud prior to interacting with metanephric mesoderm
What causes a pelvic kidney?
Metanephric kidney fails to migrate from pelvis
Metanephric mesoderm fused to form one kidney
What is it called when one kidney crosses over? and fuses to the other kidney? and the arteries are on the medial side?
Crossed ectopic kidney
Fused kidney
Non-rotation
(all three can happen simultaneously)
Where do horseshoe kidneys get stuck during ascension?
IMA
Polycystic Kidney Disease (PCKD)…remember it
It’s not hard
What is seen with multicystic dysplastic kidney disease?
Abnormal dilations of [thin segments] of nephrons
What typically causes a congenital hydroureter? Is it generally bad?
An obstruction of the ureter at the ureteropelvic junction (usually)
Not usually bad…hydronephrosis results
What is the urogenital sinus continuous with?
The allantois…which extends into the body stalk (umbilical cord)
What does the allantois form?
The urachus (becomes the median umbilical ligament)
What does the vesicle part of the urogenital sinus form?
The urinary bladder (continuous with the allantois)
What does the pelvic part of the urogenital sinus become in males?
The bladder neck and prostatic urethra (endoderm)
What does the pelvic part of the urogenital sinus become in females?
The entire urethra
What does the rest of the urethra grow from in males?
The penile urethra grows from the phallic part of the urogenital sinus (ectoderm)
What gets incorporated into the posterior wall of the developing urinary bladder?
Mesonephric ducts and ureteric bud
The connective tissue and smooth muscle of the urinary bladder and urethra are derived from what?
Splanchnic (visceral) mesenchyme (mesoderm)
What forms urchal cysts?
Epithelial cells that do not degenerate
What is it called when the urachus drains via the umbilicus?
Urachal sinus
What causes a urachal fistula?
Patent urachus…urine dribbles from urachus
What causes megacystis or megalcystis?
Posterior urethral valves that block the outflow of urine from the bladder (only in males)
What is a possible result of megacystis or megalocystis?
End-stage renal failure (20% of all ESRF d/t megacystis or megalocystis)
What does the cranial part of the urogenital ridge give rise to?
Adrenocortical primordia
What do mesothelial cells located on the posterior abdominal wall b/w the root of the dorsal mesentery and the developing gonad become?
Adrenal cortex
What accounts for the large size of the fetal adrenal gland? what happens to during the first year?
Fetal cortex is big, but it regresses during the first year
What replaces the fetal cortex?
Permanent cortex (from mesenchymal cells)
What does the adrenal medulla develop from?
Neural crest cells (neuroectoderm)
What happens with adrenogenital syndrome?
Mutation in P450c21 (steroid 21-hydroxylase gene)
What happens due to reduced steroid hormone production with adrenogenital syndrome? What is the net result?
Increased ACTH causes adrenal hyperplasia causing overproduction of androgens
