SM 188a - Development Flashcards
Which germ layer gives rise to the kidneys?
Intermediate mesoderm
What are the two key structures involved in forming the adult kidney?
Where do they come from?
What do they become?
-
Ureteric bud
- Arises from the nephric duct
- Gives rise to collecting ducts, calyxes, renal pelvis, and ureter
-
Metanephric mesenchyme
- Arises from nephrogenic cord
- Interacts wtih the ureteric bud to form the glomerulus, proximal tubule, loop of henle, and distal tubule
What is Potter’s syndrome?
What causes it?
Potter’s syndrome is the result of bilateral renal agenesis
- No kidneys
- -> oligohydraminos (not enough amniotic fluid)
- -> loss of fetal cushioning to external forces
- -> external compreession of the fetus
- > abnormal development of the face and limb
- -> Altered lung liquid movement
- > Abnormal lung formation
The permanent kidney is the ______ reiteration of primitive kidneys that form in utero
The permanent kidney is the 3rd reiteration of primitive kidneys that form in utero
Pronephros, mesonephros, metanephros
The metanephros arises from the ___________ and gives rise to the mature kidney
The metanephros arises from the intermediate mesoderm and gives rise to the mature kidney
The ________ arises from the intermediate mesoderm and gives rise to the mature kidney
The metanephros arises from the intermediate mesoderm and gives rise to the mature kidney
What structures to nephron progenitor cells (nephrogenic cord) give rise to?
Nephrogenic cord -> Metanephric mesenchyme ->
- Podocytes
- Bowman’s capsule
- Proxmial tubules
- Loop of Henle
- Distal tubules
- Connecting segments
Basically, everything except for the collecting ducts
(Nephric duct gives rise to colelcting duct and collecting system)
A cyst in the midline below umbilicus (the navel) might be a remnant of which of the following?
A. Allantois
B. Ureteric bud
C. Mesonephric tubules
D. Urogenital sinus
E. Mesonephric duct
A. Allantois
How many embryonic renal structures form in utero?
What are their fates?
Three embryonic renal structures form in utero
- Pronephros
- Forms/degenerates week 4
- Mesonephros
- Degenerates, contributes to the vas deferens in males
-
Metanephros
- Forms the permanent kidney
- Appears week 5
- Continues to develop through weeks 32-36
What is renal agenesis?
What causes it?
Renal agenesis = failure of kidneys to develop in utero
- Ureteric bud fails to develop
- Does not properly signal to the mesenchyme
- Results in renal agenesis
- May be bilateral -> Potter’s syndrome
- or unilateral -> risk of focal segmental glomerular sclerosis -> renal faliure after decades
What is Prune-Belly Syndrome?
Describe its key features
Prune-Belly Syndrome (aka Eagle-Barrett syndrome) is a birth defect characterized by…
- Absence of abdominal muscles
- Urinary tract malformations
- -> massive hydronephrosis and chronic kidney disease
- Failure of both testes to descend into the scrotum
Treatment = antibiotics to prevent UTI, possible surgery
Which embryonic structure are the glomerulus, proximal tubule, loop of Henle, and distal tubule derived from?
Metanephric mesenchyme
(interactions with the ureteric bud are critical for proper development)
Renal agenesis may result from faulty development of what structure?
A. Cloaca
B. Paraxial mesoderm
C. Lateral plate
D. Intermediate mesoderm
E. Notochord
D. Intermediate mesoderm
The kidneys develop from the intermediate mesoderm
Which structures does the primitive nephric duct give rise to?
Nephric duct -> Ureteric bud ->
- Collecting ducts
- Collecting system
(All other parts of the kidney arise from the nephrogenic cord)
Which of the following is the first-functioning embryonic/fetal kidney?
A. Urogenital sinus
B. Pronephros
C. Mesonephros
D. Metanephros
E. Nephrogenic cord
C. Mesonephros
- The pronephros (B) forms first but is never functional
- The metanephros takes over from the mesonephros to form the permanent kidney
