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44 Cards in this Set

  • Front
  • Back
Most primordia of the UG system is derived from ___? What else is it derived from?
Intermediate Mesoderm - MOST

Endoderm & Splanchnic mesoderm - SOME
After embryonic folding, where does the UG precursor develop?
On posterior wall of coelom; Int Mesoderm forms a Urogenital RIDGE
What is contained in the Urogenital Ridge?
-Kidney primordia
-Gonad primordia
UG Ridge Derivatives:
-Genital Ducts
-Adrenal cortex
What is the consequence of the urinary and genital systems having a SHARED origin?
-Often have SHARED anomalies
What portion of the UG system is derived from Endoderm?
Epithelial linings of
-Urinary bladder
-Vagina (lower part)
What part of UG system derives from Splanchnic mesoderm?
Walls of organs lined w/ epithelial endoderm
Site of Kidney Tubule formation:
Lateral part of UG Ridge - aka Nephrogenic Cord
2 Kidneys seen during development of UG system:
What is the Mesonephric kidney?
-Transient kidney present in the thoracolumbar region @ 4-12 wks.
-Functional from wks 6-12
What 2 components make up the Mesonephric kidney?
-Mesonephric duct
-Mesonephric tubules
3 steps in formating Mesonephric Ducts:
1. Solid cord of cells forms, extends caudally thru UG ridge.
2. Cord gains a lumen
3. Ducts fuse w/ cloaca @ 26d
What ARE mesonephric tubules?
Primitive nephrons
How do the Mesonephric Tubules develop?
Cranially -> Caudally
(first ones disappear before the last caudal ones form)
What is the fate of Mesonephric DUCTS in males?
-Vas deferens
-Seminal vesicle
-Ejaculatory duct
What is the fate of the Mesonephric Ducts in Females?
-Remnant strutures in uterine mesentary
What is the fate of the Mesonephric Tubules in Males?
Efferent ductules
What is the fate of the Mesonephric Tubules in Females?
Remnant structures in ovarian mesentary
What is the METANEPHRIC kidney?
The permanent kidney!
When does the permanent kidney first appear?
At week 5
What are the 2 primary precursors of the Metanephric kidney?
-Ureteric bud
-Metanephric Mesenchyme
What are the Ureteric bud and Metanephric Mesenchyme derived from?
Intermediate Mesoderm
What is the Ureteric Bud?
A derivative of the Mesonephric duct as it bends medially to join the cloaca.
Where is Metanephric Mesenchyme found?
At the caudal end of UG ridge
How do the 2 Primary precursors of the metanephric kidney develop?
By reciprocal Inductive Interactions between each other.
What 3 things mediate inductive interactions between the kidney's primary precursors?
1. Growth factors
2. Secreted factors
3. ECM
What is Renal Agenesis?
Absence of a kidney
What sex is Renal Agenesis more commonly seen in?
What's more common/severe; unilateral or bilateral renal agenesis?
Unilateral -> 1/600-1000 births

(Bilat = 1/2000 & more severe)
What side is unilateral renal agenesis usually seen on?
What is this associated with?
-Assoc w/ single umbilical artery
What is BILATERAL renal agenesis associated with? (4 things)
-Pulmonary hypoplasia
-Potter's facial sequence
-GI/Heart/UG/NS anomalies
What is potter's facial sequence?
Flattened facial features
What causes Nephron formation?
Inductive interactions between Ureteric bud and Metanephric mesenchyme
What is the expanded end of the ureteric bud called, and what is its function?
The Ampulla - a primary source of inductive signals for nephron formation.
What is the consequnce of ampullae disappearance?
When they're all gone, no new nephrons form.
What are the steps in Nephron Formation (4)?
1. Metanephric mesenchyme condenses around ampulla
2. Mesenchyme compacts and transforms into epithelium
3. Epithelial vesicle fuses with the ampulla
4. Epithelial vesicle elongates into s-shaped tubule.
What does the vascular component of the nephrons develop from?
Intersegmental arteries between somites - induced to grow toward the forming kidney.
What causes this vascular sprouting?
Induced mesenchyme that secretes angiogenic growth factors.
What forms Collecting ducts, Calices, the renal Pelvis, and Ureter?
Branching of the ureteric bud - about 15 generations.
What are the key features of collecting system branching?
1. Early generations grow little before next branching occurs.
2. End polar branches grow fast
-Results in kidney bean shape
What generations of ureteric bud branching forms the Calices, Renal Pelvis, and Ureters?
What forms Collecting ducts?
Branches distal to the 6th generation.
What are "Renal Lobes"?
Large, pyramidal-shaped structures that constitute the macroscopic kidney organization.
When are lobes visible or not?
-Visible in embryo/fetus
-Merge and become indistinct during childhood.