Lecture 19 - Embyrological Development Flashcards
What embryonic layer gives rise to the kidneys?
What part of this embryonic layer in particular?
Mesoderm
Intermediate mesoderm
What are the 3 systems that develop sequentially leading to the formation of the kidneys?
Pronephros
Mesonephros
Metanephros
What region of the embryo does the pronephros first arise in?
Cervical region
Which embryonic layer gives rise to the bladder??
Endoderm
What is the purpose/function of the pronephros?
Has no function (not used)
Gives rise to the pronephric DUCT
How does the pronephric duct travel in the embryo?
From the cervical region where it’s formed down to the cloaca
What is the importance of the pronephric duct?
How does the name of the duct change and why?
Gives rise to mesonephric tububles caudal to the duct
As the pronephros degenerates it becomes the mesonephric duct
What 2 structures are considered the embryonic kidney?
What can this structure do?
Mesonephric tubules + Mesonephric duct = embryonic kidney
Can filter stuff out of body but can’t conserve water
What important structure does the mesonephric duct sprout/give rise to?
Ureteric bud
What does the ureteric bud give rise to?
Metanephros/kidney
What other important system (except for the urinary system) does the mesonephric duct have an important role in developing?
Male reproductive system
What is the name of the tissue which releases growth factors leading to the formation of the ureteric bud from the mesonephric duct?
Metanephric blastema
What structure gives rise to the collecting system?
What structure gives rise to nephrons?
Ureteric bud = collecting system
Metanephric blastema = nephron
What is considered the collecting system formed by which structure?
Ureteric bud
Collecting duct, major calyces, minor calyces and ureters
What structure forms the collecting system?
What is considered the collecting system?
Ureteric bud
Collecting duct, major calyces, minor calyces and ureters
What anatomical location does the Metanephric kidney first appear in?
Pelvic region
How does the Metanephric kidney migrate? (where does it end up?)
What structures does it take with it as it does so?
Moves from caudal end to cranially
It takes arteries from teh aorta as it ascends to sit under the adrenal glands
What congenital defect can occur if the ureteric bud fails to interact with the intermediate mesoderm/Metanephric blastema?
Renal agenesis
(Kidneys dont form)
What are some other defects that can occur with kidney development that isn’t renal agenesis?
Abnomral migration
Duplication defects
Ectopic ureter
Cystic disease
What is a pelvic kidney?
When a kidney gets trapped in the pelvic region
What is a horseshoe kidney?
When the poles of the kidney fuse together so they’re in in the shape of a big horseshoe
This means they get caught by the inferior mesenteric artery on ascent
What artery does a horseshoe kidney get stuck on on ascent?
Inferior mesenteric artery
What may happen if the ureteric bud splits too early?
Ectopic urethral openings
2 renal pelvises connecting to 1 ureter
Or 2 ureters connecting to 1 renal pelvis
What is the dilated structure at the end of the hindgut called?
Cloaca
What structre does the bladder and urethra come from?
Cloaca
What is the important structure that separates urinary (bladder and urethra) development from GI tract development in the hindgut?
Urorectal septum
What structures does the urorectal septum separate?
Urogential sinus
Anorectal canal
What is the urachus?
What is the allantois?
Structure continuos with the urogential sinus formed from the Allantois
Structure where urine was initially drained from in the 1st trimester
What 3 parts is the urogenital sinus split into?
Superior part connecting to umbilicus
Middle/pelivc part
Inferior/caudal part
What does the superior pat of the Urogential sinus form?
Bladder
What does the pelvic part of the urogenital sinus form?
Females = urethra and some reproductive tract
Males = prostatic + membranous urethra
What does the caudal/inferior part of the Urogential sinus form?
Females = part of female repro tract
Males = spongy urethra
What part of the female reproductive tract is formed by teh lower part of teh urogential sinus?
What about male?
Clitoris
Penis/spongy urethra
Briefly describe the formation of the female bladder and urethra:
Mesonephric ducts reach urogential sinus
Ureteric bud sprouts from mesonephric ducts
Urogenital sinus expands and mesonephric duct regresses
Ureteric bud opens into urogenital sinus
What structure is formed by the mesonephric duct being absorbed/drawn into the bladder??
Trigone
Briefly describe the formation of the male bladder and urethra
Mesonephric ducts (MD) reach urogenital sinus (UGS)
Ureteric bud sporuts from MD
Smoooth muscle appears and UGS expands
UB and MD make independant openings in UGS (trigone)
Which stage of kidney development forms the Trigone?
Mesonephros
What week of development is the kidney functional and ascending to secreted urine?
Week 10
What week of development is the pronephros degraded by?
Week 4
