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Flashcards in UG devo (both lectures) Deck (76):
1

What is the precursor for structures below:

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

Intermediate mesoderm

2

What structures in UG come from Endoderm?

Epithelial lining of Urinary Bladder and urethra

3

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

Splanchnic Mesoderm

4

• The Intermediate Mesoderm is Observable at day_____

• It eventually separates from the ________

18-20

paraxial mesoderm

5

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

Nephrogenic Cord

6

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]

7

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

Nephrogenic Cord

8

Two components of mesonephric kidney (a transient functional structure)

Meonephric duct

mesonephric tubules

9

Mesonephric Duct is an Important Source of_______ for Kidney Structures

• A solid cell cord which eventually canalizes

• Extends________ through nephrogenic cord

Inductive signals caudally

10

Mesonephric duct fuses with _____ at day 26

Cloaca

11

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

Cloaca

12

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

13

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

Pelvic Region

Nephrogenic Cord

14

2 Precursors for Metanephric kidney are derived from :

• _________ = ureteric bud

• ________ =metanephric lastema

Intermediate Mesoderm

Metanephric Diverticuclum

Metanephrogenic Mesenchyme

15

___________ 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

16

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

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

17

• 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

18

Causes of Potters Syndrome

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

19

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

Oligohydramnios

20

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

Polyhydramnios

21

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

22

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

 

Ampulla

23

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 

24

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

[Fgf2, Bmp7] 

25

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

26

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

 

27

•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

28

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

29

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

30

31

What happens in MDK to the contralateral kidney? 

What happens if MDK is bilateral?

• Contralateral kidney hypertrophies
• Bilateral disease is rare; fatal

32

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)

33

Remodeling & Differential Growth of the Branching Metanephric Diverticulum 
results in Formation of the 

Collecting Ducts,Calyces, Pelvis and Ureter

34

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

 

35

Branches distal to the 5th & 6th generations form 

 

Collecting Ducts

36

• In the kidney, Nephrons and Collecting Ducts are organized into larger structures called _____
 

Renal Lobes

37

• 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

38

• 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

39

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

40

The Metanephric Kidney Develops in the Pelvis and “Ascends” into the Abdomen because of Differential Growth of the __________

 

 

Embryonic Body 

41

Pelvic & Lumbar Kidneys  are due to: 

Extra renal vessels result from:

Failed or incomplete ascent

Failure to atrophy during kidney ascent

42

Polycystic Kidney disorder is what kind of disease?

Both autosomal dominant and recessive 

43

Common neoplasms in children in the kidney:

What chromosome is it located?

Nephroblastoma = Wilms Tumor

chromosome 11

44

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

 

 

45

• 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

46

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

47

Division of the Cloaca Provides for : 
The Cloaca is Subdivided by the :

 

Separate Outlets for the UG & GI

Urorectal Septum

48

• The Primary (Primitive) UG Sinus is located______ 
• The Anorectal Canal is located_______

ventrally

dorsally

49

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

50

Remodeling of the Posterior Wall of the Bladder Results in 
Formation of the 

Trigone Region

51

• The trigone is associated with entrance of the______ & exit of the ______ 
 

ureters

urethra

52

• 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

53

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!

54

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

55

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
 

56

What happens to the ureter and kidney over time in patient with ureteral reflux?

see scarring, tortuous and dialate ureters, increased risk of infection

57

• 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

58

• 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

59

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

60

Bladder Exstrophy
• 1 per hundred if positive ___
• Male:Female _____
• Failure of _________
 

FH

3:1

medial mesenchymal migration

61

Bladder Extrophy

Males oftne with:

• Females with :
• Gonadal structures_____ and babies typically______

epispadius

shortened vagina; bifid clitoris

normal

healthy

62

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

63

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

64

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

65

The Fate of the Definitive UG Sinus is Different in 
Males & Females

Females
Pelvic portion -->

Phallic Portion -->

Pelvic--> lower half of vagina

phallic--> vestibule

66

Agenesis & Atresia of the Urethra : Atresia is associated with 

urinary obstruction & Prune Belly Syndrome

67

• Mucosal folds which obstruct the lumen of the urethra 
• A Common cause of renal failure in boys

Posterior Urethral Valves 

68

 posterior urethral valves
• Occurs only in_____
• Obstructing valves leads to 
 

males

severe obstruction of urinary tract and irreversible renal dysplasia

69

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!

70

Pathology of PUV:

• Obstructing membrane at _______
• Apprearane of kidneys on utlrasound:
• Valves easily _____
• Outcome largely predetermined

membranous urethra

Small echo-bright kidneys

ablated

71

 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

72

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 

73

Metanephric kidney formation depends on inductive interactions between 
the _______ and _______

 

metanephric diverticulum and the metanephrogenic mesenchyme

74

• The ureter, pelvis, calcyes and collecting ducts form from the 

metanephric diverticulum

75

• The nephrons form from metanephrogenic mesenchyme and glomeruli are 
derived from

 sprouts of intersegmental arteries

76

The_______ part of the divided cloaca becomes the primitive UG sinus from 
which the urinary bladder and urethra are formed

ventral