UG devo (both lectures) Flashcards by Meghan May

What is the precursor for structures below:

Kidney, Caylces, Pelvis, Ureters, Gonads, Genital Ducts

Intermediate mesoderm

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What structures in UG come from Endoderm?

Epithelial lining of Urinary Bladder and urethra

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Smooth Muscle & CT in the walls of Bladder and ureter are derived from

Splanchnic Mesoderm

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The Intermediate Mesoderm is Observable at day_____
It eventually separates from the ________

18-20

paraxial mesoderm

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Intermediate Mesoderm forms the ___________[later called the Urogenital (UG) Ridge] (covered with Coelomic Epithelium)

Nephrogenic Cord

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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]

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A Mesonephric Kidney Forms Within the__________in the Thoracolumbar Region of the Embryo

Nephrogenic Cord

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Two components of mesonephric kidney (a transient functional structure)

Meonephric duct

mesonephric tubules

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Mesonephric Duct is an Important Source of_______ for Kidney Structures

A solid cell cord which eventually canalizes
Extends________ through nephrogenic cord

Inductive signals caudally

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Mesonephric duct fuses with _____ at day 26

Cloaca

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The dilated, caudal end of the primitive hindgut; A transient, common outlet for the UG & GI systems

Cloaca

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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

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The Metanephric (Mature) Kidney Forms in the _____of the Embryo from the Caudal Aspect of the ________

Pelvic Region

Nephrogenic Cord

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2 Precursors for Metanephric kidney are derived from :

_________ = ureteric bud
________ =metanephric lastema

Intermediate Mesoderm

Metanephric Diverticuclum

Metanephrogenic Mesenchyme

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___________ 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

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The Epithelial-Mesenchymal interactions between the metanephric diverticulum metanephrogenic mesenchyme are mediated by

growth factors, secreted factors, patterning genes & changes in the extracellular matrix

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• 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

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Causes of Potters Syndrome

• Renal agenesis
• Severe urinary obstruction
• Features of facial compression,
growth retardation, limb deformities

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• Too little amniotic fluid
– Associated with renal agenesis, polycystic kidney disease, urethral obstruction
– Chronic amniotic leak

Oligohydramnios

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Excessive amniotic fluid
– Associated with diabetes, multiple gestation, anencephaly, esophageal atresia

Polyhydramnios

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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

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Expanded tips of MD called________, a key signaling center for nephron induction

Ampulla

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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

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MD signals _____ and _____prevents MM cell apoptosis and induces a subset of
MM cells to aggregate around ampulla

[Fgf2, Bmp7]

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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

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UG devo (both lectures) Flashcards

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