Yan Flashcards
What is the urinary system derived from?
Intermediate Mesoderm
What embryological phase does kidney formation happen during?
the embryonic period…specifically weeks 4-8
What are the names of the 3 sets of kidneys?
1st set: pronephros
2nd set: mesonephros
3rd set: metanephros
While the 2 first sets of kidneys disappear…what is the lasting legacy of the 2nd set…the mesonephros?
The mesonephric duct remains & helps form the male reproductive system–esp the ejaculatory duct.
It also induces the formation of the 3rd kidney set.
Where is the pronephros set of kidneys found? What is its function?
When does it begin?
When does it end?
cervical region
nonfunctional
begins & ends w/i the 4th week.
Where is the mesonephros set of kidneys found? What is its functional status? When does it begin? When does it end? What remains?
thoracolumbar region temporarily functional 4th week ends by end of 2nd month (week 8) mesonephric duct remains in males
When does the metanephros kidney begin? End?
What is its functional status?
Begins 5th week.
Never ends!! : )
The final functional set of kidneys!
What do the gonads form from? When? What set of kidneys is this associated w/?
urogenital ridge
2nd month
mesonephric kidneys
How is it that the mesonephric kidneys induce the formation of the metanephric kidneys?
A ureteric bud (caudal portion of intermediate mesoderm) outgrows from the mesonephric duct…This bud penetrates the metanephric tissue & induces the formation of the metanephric blastema…
What happens to the ureteric bud once it penetrates the metanephric tissue?
It branches to form the renal pelvis, the major calyces, the minor calyces, & the collecting ducts.
How does the nephron form?
Exact order?
communication from the collecting tubules’ epithelial cells & the surrounding mesenchymal cells.
Metanephric Tissue Caps (mesenchymal cells)–>renal vesicles–>S-shaped tubule–>Bowman’s capsule
What does the nephron NOT include?
Collecting tubules
Which two cell types communicate during kidney formation? What does each whisper to the other?
Mesenchymal cells & epithelial cells
Mesenchymal–>epithelial: branch!
Epithelial–>mesenchymal: Make that nephron!
What are 2 important congenital conditions that affect the kidney?
Autosomal Recessive Polycystic Kidney Disease
Autosomal Dominant Polycystic Kidney Disease
With autosomal recessive polycystic kidney disease…when does a person experience renal failure? Which part of their kidney is affected?
Experience renal failure usu in infancy or childhood.
Cyst forms in the collecting tubules.
With autosomal dominant polycystic kidney disease…when does a person experience renal failure? Which part of their kidney is affected?
Not usu until adulthood.
Cyst formation in all parts of the nephron
How do you get duplication of the ureter?
You can get duplication of the ureter when the ureteric bud branches before it fully penetrates the metanephric blastema…
the earlier it branches, the less likely it will converge again.
What are the 2 types of ureter duplications?
Partial Splitting: here they come back together again…probably a later branch
Complete Splitting: here they don’t come back together (prob an early branch) & the second ureter empties into an ectopic ureter opening–like the vagina, urethra, or a vestibule.
The kidneys’ connection to the urogenital sinus is thru the _______. They move _____.
The gonads’ connection to the urogenital sinus is thru the _______. They move _____.
ureter. upward/ascend
mesonephric duct. downward/descend.
**They essentially switch positions.
The entrances of the mesonephric duct & the ureter into the urogenital sinus are _____.
independent.
What are 2 possible positioning defects of the kidney?
one kidney or both could get stuck in the pelvis & never ascend…
OR you could get a horseshoe kidney where they fuse & then get stuck on the inferior mesenteric artery.
What 2 things does the cloaca form? What structure separates them?
Urogenital sinus (anteriorly) Anal canal (posteriorly) **separated by the urorectal septum
What are the 3 components of the urogenital sinus?
Upper: Bladder
Middle: Pelvic
Lower: Phallic
In the upper urogenital sinus…what initially connected the bladder to the umbilicus? What later connected it? What is this structure called in adults?
Originally: allantois
Then: Urachus
In adults: called median umbilical ligament
What does the middle pelvic section of the urogenital sinus form?
prostatic & membranous part of the urethra
What does the lower part of the urogenital sinus form?
The phallic…the differences b/w the sexes.
What is the trigone area of the bladder? What is it derived from? How does this differ from the rest of the bladder? Does this change? What if it doesn’t?
It is a smooth triangular portion of the bladder formed by the opening of ducts/ureters.
It is therefore mesodermal in origin. Most of the bladder is endodermal in origin. With time this changes & the trigone becomes mainly endodermal, too. If this replacement doesn’t happen…you can develop tumors.
What is the trigone area of the bladder? What is it derived from? How does this differ from the rest of the bladder? Does this change? What if it doesn’t?
It is a smooth triangular portion of the bladder formed by the opening of ducts/ureters.
It is therefore mesodermal in origin. Most of the bladder is endodermal in origin. With time this changes & the trigone becomes mainly endodermal, too. If this replacement doesn’t happen…you can develop tumors.
What are 3 important bladder defects?
Urachal Fistula
Exstrophy of the Bladder
Epispadias
What are 3 important bladder defects?
Urachal Fistula
Exstrophy of the Bladder
Epispadias
What is a urachal fistula?
It is the incomplete closing of the allantois. This allows urine to drain from the umbilicus.
What is a urachal fistula?
It is the incomplete closing of the allantois. This allows urine to drain from the umbilicus.
Some variants of the urachal fistula issues…what is a urachal cyst & a urachal sinus?
Urachal Cyst: local area of allantois persists, dilation, blockage sort of…
Urachal Sinus: blind sac near the opening of the umbilicus where the allantois persists
Some variants of the urachal fistula issues…what is a urachal cyst & a urachal sinus?
Urachal Cyst: local area of allantois persists, dilation, blockage sort of…
Urachal Sinus: blind sac near the opening of the umbilicus where the allantois persists
What is exstrophy of the bladder?
Ventral body wall defect
Bladder mucosa exposed
lack of mesodermal migration to proper location & rupturing of the thin layer of ectoderm.
Always includes epispadias
What is exstrophy of the bladder?
Ventral body wall defect
Bladder mucosa exposed
lack of mesodermal migration to proper location & rupturing of the thin layer of ectoderm.
Always includes epispadias
What are epispadias?
A malformation in which the urethra opens on the dorsum of the penis. Always seen w/ exstrophy of the bladder.
What are epispadias?
A malformation in which the urethra opens on the dorsum of the penis. Always seen w/ exstrophy of the bladder.
