UG devo (both lectures) Flashcards
What is the precursor for structures below:
Kidney, Caylces, Pelvis, Ureters, Gonads, Genital Ducts
Intermediate mesoderm
What structures in UG come from Endoderm?
Epithelial lining of Urinary Bladder and urethra
Smooth Muscle & CT in the walls of Bladder and ureter are derived from
Splanchnic Mesoderm
- The Intermediate Mesoderm is Observable at day_____
- It eventually separates from the ________
18-20
paraxial mesoderm
Intermediate Mesoderm forms the ___________[later called the Urogenital (UG) Ridge] (covered with Coelomic Epithelium)
Nephrogenic Cord
Specification of kidney-forming ability to the intermediate mesoderm is mediated by signals from __________ and transcription factors ____,____,____ expressed in intermediate mesoderm
paraxial mesoderm
[Pax2, Pax8 & Lim1]
A Mesonephric Kidney Forms Within the__________in the Thoracolumbar Region of the Embryo
Nephrogenic Cord
Two components of mesonephric kidney (a transient functional structure)
Meonephric duct
mesonephric tubules
Mesonephric Duct is an Important Source of_______ for Kidney Structures
- A solid cell cord which eventually canalizes
- Extends________ through nephrogenic cord
Inductive signals caudally
Mesonephric duct fuses with _____ at day 26
Cloaca
The dilated, caudal end of the primitive hindgut; A transient, common outlet for the UG & GI systems
Cloaca
Mesonephric Tubules = Immature Nephrons
- Inductive signals from the ________ induce tubule formation
- Differentiation occurs in a _____ to ______ direction along the nephrogenic cord
- All tubules induced________ present at same time
mesonephric duct
cranial to caudal
are NOT
The Metanephric (Mature) Kidney Forms in the _____of the Embryo from the Caudal Aspect of the ________
Pelvic Region
Nephrogenic Cord
2 Precursors for Metanephric kidney are derived from :
- _________ = ureteric bud
- ________ =metanephric lastema
Intermediate Mesoderm
Metanephric Diverticuclum
Metanephrogenic Mesenchyme
___________ interactions occur between the Metanepric
Diverticulum and the Metanephrogenic Mesenchyme
Reciprocal Inductive
*Metanephic diverticulm encourages differentiation of metaphrogenic mesenchyme
metaphrogenic mesenchyme encourages Branching of metanephric diverticulm
The Epithelial-Mesenchymal interactions between the metanephric diverticulum metanephrogenic mesenchyme are mediated by
growth factors, secreted factors, patterning genes & changes in the extracellular matrix
• A full term infant was born and had severe
respiratory distress. He developed a
pneumothorax and required mechanical
ventilation. The maternal history was positive
for oligohydramnios.
• On exam the infant was small for age. There
were unusual facial features and limb
deformities.
• The patient expired within 24 hours.
Potters Syndrome
Causes of Potters Syndrome
• Renal agenesis
• Severe urinary obstruction
• Features of facial compression,
growth retardation, limb deformities
• Too little amniotic fluid
– Associated with renal agenesis, polycystic kidney disease, urethral obstruction
– Chronic amniotic leak
Oligohydramnios
Excessive amniotic fluid
– Associated with diabetes, multiple gestation, anencephaly, esophageal atresia
Polyhydramnios
Metanephrogenic Mesenchyme (MM) signals ______ induce formation of Metanephric Diverticulm
Inductive Interactions Between the Metanephric Diverticulum
(MD) and the Metanephogenic Mesenchyme (MM) Result in:________
GDNF, RA
Nephron Formation
Expanded tips of MD called________, a key signaling center for nephron induction
Ampulla
The varying nature of signals from the ampulla directs the arrangement of ____ and ______. Ampullae begin to disappear at about ____weeks. No new nephrons are formed after all ampullae disappear
nephrons and collecting ducts
32
MD signals _____ and _____prevents MM cell apoptosis and induces a subset of
MM cells to aggregate around ampulla
[Fgf2, Bmp7]
Early Stages of Nephron Formation
Signals from the ampulla cause the metanphrogenic mesenchyme to aggregate and form an ______ and involves Differentiation and Differential Growth of the S-Shaped Tubule
epithelial vesicle
Nephron Derivatives of
the S-Shaped Tubule
Include:
• From the Proximal Part (P) = __________
• From the Middle Part (M) = ____________
• From the Distal Part (D) =____________
- Distal Tubule & loop of Henle
- Proximal Tubule
- Renal Corpuscle
- Vascular Spouts From __________are Induced to Grow Toward the Forming Kidney and form the vasculature of the kidney
- Only induced________ secretes angiogenic growth factors [VEGF] that attracts the vascular sprouts to the forming kidney
Intersegmental Arteries
mesenchyme
A healthy one month old boy was seen in nephrology clinic for a history of his mother
having an abnormal prenatal ultrasound.
• He was well-appearing, had normal blood pressure, and was growing well. He had a right flank mass.
DDx?
• Hydronephrosis
– Obstruction of the urinary tract
• Cystic Kidney disease
– Polycystic kidney disease
– Multicystic dysplastic kidney disease
• Renal tumor
You see this on ultrasound from a little boy complaining of right flank pain.
Dx?
Is this often unilateral or bilateral?
What’s the pathology?
Multicystic Dysplastic Kidney
• Most often unilateral (polycystic kidney disease is bilateral)
• Multiple cysts of varying sizes and kiney is non-functioning
• Pathology—primitive ductules and cartilage seen; atretic ureter
What happens in MDK to the contralateral kidney?
What happens if MDK is bilateral?
- Contralateral kidney hypertrophies
- Bilateral disease is rare; fatal
MDK
- Potential for abnormalities of the contralateral kidney, such as vesicoureteral reflux, approx. ______
- Hypertension is potential complication
- Failure of a large MCKD to regress may be indication for_______
- The cause is:
28%
nephrectomy
NON-genetic (polycystic is genetic)
Remodeling & Differential Growth of the Branching Metanephric Diverticulum
results in Formation of the
Collecting Ducts,Calyces, Pelvis and Ureter
There are about 15 generations of metanephric diverticulum branches; Key features of the branching process include:
- ________ growth of early generations
- _______ growth of polar branches
- Expansion of the _______generations of branches to form the Calyces, Pelvis and Ureters
Little
Faster
3rd-6th
Branches distal to the 5th & 6th generations form
Collecting Ducts
• In the kidney, Nephrons and Collecting Ducts are organized into larger structures called _____
Renal Lobes
- Each kidney lobe ends in a pyramid shaped Renal Papilla which empties into a____
- In the Embryonic and Fetal Kidney, the Renal Lobes are visible ______
Minor Caylx
externally
• Anomalies of the Urinary System Organs are common
but _________
• Urinary System anomalies are often associated with
other anomalies, primarily ________
not always clinically significant
genital system anomalies
Four anomalies seen in kidneys
Hypoplastic (small but may still have normal fnx~ possibly d/t abnormal devo)
Dysplastic kidneys
Duplications (of ureter or kidney~ can be partial or complete)
Horseshoe Kidney~ fusion prevents complete ascent
The Metanephric Kidney Develops in the Pelvis and “Ascends” into the Abdomen because of Differential Growth of the __________
Embryonic Body
Pelvic & Lumbar Kidneys are due to:
Extra renal vessels result from:
Failed or incomplete ascent
Failure to atrophy during kidney ascent
Polycystic Kidney disorder is what kind of disease?
Both autosomal dominant and recessive
Common neoplasms in children in the kidney:
What chromosome is it located?
Nephroblastoma = Wilms Tumor
chromosome 11
Clincal presentation of Ureretopelvic Jnx obstruction
In infant:
In young adult:
– Infant: flank mass, UTI, failure to thrive, sepsis
– Older child or adult: flank pain, colicky pain, UTI, hematuria
- An 21year old college student presents with a history of severe right flank pain following celebration of his 21st birthday in which he drank copius amounts of an inhibitor of vasopressin. On exam, the patient was in pain and he had a unilateral right flank mass.
- Past medical history: significant for several UTI’s as a child, which were never investigated
- Review of systems: he has had recurrent, intermittent right sided flank pain
Dx?
What are significant findings?
Uretopelvic junction obstruction
*right flank pain
*hx of UTIs and he’s male
*recurrent remittent right sided flank pain
*Diarhesis enhances the obstruction of the urinary tract
Diagnostic studies for UPJ:
Why is it important to Dx young?
ultrasound (anatomy) or renal scan, intravenous pyelogram (functional studies); see fluid back up to kidney
Dx young bc you increase risk of infection thus fibrosis of the kidney. While the obstruction can be fixed later, damage such as fibrosis is permanent and you end up with kidneys that don’t fnx as well
Division of the Cloaca Provides for :
The Cloaca is Subdivided by the :
Separate Outlets for the UG & GI
Urorectal Septum
- The Primary (Primitive) UG Sinus is located______
- The Anorectal Canal is located_______
ventrally
dorsally
The Cranial or Vesicle Part of the Primary UG Sinus Enlarges:
• The cranial part of the UG sinus forms_________
• Lining derived from______
• Smooth muscle & CT of the bladder wall is derived from the surrounding _________
urinary bladder & urethra (part)
endoderm
splanchnic mesoderm
Remodeling of the Posterior Wall of the Bladder Results in
Formation of the
Trigone Region
• The trigone is associated with entrance of the______ & exit of the ______
ureters
urethra
• In males, differential growth results in the mesonephric ducts
opening into _____ rather than _______
* in the male, the mesonephric duct distal to the metanephric diverticulum
becomes the______
urethra rather than urinary bladder
vas deferens
Anomalies of the Urachus arise from
failure of regression of these structures; [allantois & urachus]
–patent openings: urancus doesn’t close to median ligament; you can see pee come out the belly button!
Exstrophy of the Bladder
• A defect of the ________
• The lining of the bladder and the urethra is _______
• Associated with _______
ventral abdominal wall
open to the surface
UG & skeletal anomalies
Ureteral Reflux
• The higher the grade of reflux:
– the greater the risk for ______
– the more______ the anatomy is
– spontaneous resolution is______
***surgical intervention may be necessary
scarring
abnormal
less likely
What happens to the ureter and kidney over time in patient with ureteral reflux?
see scarring, tortuous and dialate ureters, increased risk of infection
• A______ ureter leads to reflux, which can lead to recurrent kidney infections and
subsequent atrophy of the kidney.
• Treatment is:
lateralized
antibiotic prophylaxis and/or surgical repair
• Four year old female
• Potty trained but having urgency and
dampness
• Has had three urinary tract infections in the
past year, all with fever
• Mother was told she had childhood problems,
has a low abdominal scar, has no other details
Ureteral reflex
Healthy 28 year old female, G1, P0 at 20 weeks gestation
• Routine prenatal ultrasound reveals an healthy fetus but the bladder is not visualized
• Kidneys are normal
• Amniotic fluid is normal
• Sex is indeterminate
• What is the diagnosis??
Bladder Exstrophy
Bladder Exstrophy
• 1 per hundred if positive ___
• Male:Female _____
• Failure of _________
FH
3:1
medial mesenchymal migration
Bladder Extrophy
Males oftne with:
- Females with :
- Gonadal structures_____ and babies typically______
epispadius
shortened vagina; bifid clitoris
normal
healthy
Exstrophy Repair: Surgery performed shortly after birth and babies hospitalized
for 10-14 days
ISSUES remaining are:
Incontinence is a major long term issue
• Upper tracts at risk after repair
The Extent of the Urethra Formed from the Caudal Part of
UG Sinus Differs in Males & Females
Males:
Females:
Males: Proximal portion of Prostatic Urethra
Female: Most of it
The Fate of the Definitive UG Sinus is Different in
Males & Females
Males
Pelvic portion –>
Phallic Portion –>
Pelvic –> Distal prostatic and Membranous urethra
Phallic Portion –> Penile urethra
The Fate of the Definitive UG Sinus is Different in
Males & Females
Females
Pelvic portion –>
Phallic Portion –>
Pelvic–> lower half of vagina
phallic–> vestibule
Agenesis & Atresia of the Urethra : Atresia is associated with
urinary obstruction & Prune Belly Syndrome
- Mucosal folds which obstruct the lumen of the urethra
- A Common cause of renal failure in boys
Posterior Urethral Valves
posterior urethral valves
• Occurs only in_____
• Obstructing valves leads to
males
severe obstruction of urinary tract and irreversible renal dysplasia
mom is 22 weeks, notes baby isn’t moving around as much, get ultrasound:
• Finding include
– Massively distended bladder
– Poorly developed chest cavity
– Small, echo-bright hydronephrotic kidneys
– Oligohydramnios
• What is the diagnosis??
Posterior urethral vavles: only in males!
Pathology of PUV:
- Obstructing membrane at _______
- Apprearane of kidneys on utlrasound:
- Valves easily _____
- Outcome largely predetermined
membranous urethra
Small echo-bright kidneys
ablated
The kidney and ureter form from ______; the lining of the
urinary bladder and urethra are derived from _______
intermediate mesoderm
endoderm and the wall from splanchnic mesoderm
A temporary kidney, the_______, provides the mesonephric duct, the
source of the metanephric diverticulum
• Formation of the metanephric (mature) kidney begins in _____
mesonephros
week 5
Metanephric kidney formation depends on inductive interactions between
the _______ and _______
metanephric diverticulum and the metanephrogenic mesenchyme
• The ureter, pelvis, calcyes and collecting ducts form from the
metanephric diverticulum
• The nephrons form from metanephrogenic mesenchyme and glomeruli are
derived from
sprouts of intersegmental arteries
The_______ part of the divided cloaca becomes the primitive UG sinus from
which the urinary bladder and urethra are formed
ventral
