Embryology Flashcards
What are the three embryonic renal structures formed in utero?
- Pronephros
- Mesonephros
- Metanephros (becomes kidney)
When does the pronephros degenerate?
Week 4
When does the Mesonephros function as the interim kidney?
In the 1st trimester
What structure does the mesonephros contribute to in males?
Vas deferens
When does the metanephros appear?
5th week
When does the metanephros develop into the kidney?
Weeks 32-36
What is the ureteric bud an outgrowth of?
Mesonephric (Wolffian) duct
What does the ureteric bud give rise to?
- Ureter
- Pelvis
- Calyxes
- Collecting ducts
What does the metanephric mesenchyme (aka metanephric blastema) give rise to?
- Interacts with ureteric bud
- Interaction forms glomerulus to distal tubule
What can an aberrant interaction between the ureteric bud and metanephric mesenchyme result in?
Can result in renal agenesis or multicystic dysplastic kidney
What is the most common pathologic cause of prenatal hydronephrosis?
Ureteropelvic junction obstruction (detected by prenatal ultrasound)
What are the effects of oligohydramnios (POTTER sequence)?
- Limb deformaties
- Facial anolmalies (low-set ears, retrognathia [retracted jaw], flattened nose)
- Compression of chest and lack of amniotic fluid aspiration into fetal lungs
- Pulmonary hypoplasia (cause of death)
How can the effects of POTTER sequence be remembered?
POTTER
- Pulmonary hypoplasia
- Oligohydramnios (trigger)
- Twisted face
- Twisted skin
- Extremity defects
- Renal failure (in utero)
How does Horseshoe kidney develop?
Inferior poles of kidney fuse abnormally
- As they ascend from pelvis during fetal development, horseshoe kidneys get trapped under the IMA and remain low in the abdomen
What pathologies are associated with horseshoe kidney?
- Hydronephrosis (e.g uretopelvic junction obstruction)
- Renal stones
- Infection
- Increased risk of renal cancer
What kind of syndromes are associated with Horseshoe kidney?
- Turner syndrome
- Aneuploidy 13, 18, 21
What can be seen in the contralateral kidney with congenital solitary functioning kidney?
Compensatory hypertrophy, hyperfiltration, risk of focal segmental glomerular sclerosis (FSGS)
- Anomalies in contralateral kidney common
What is unilateral renal agenesis due to?
Ureteric bud failing to develop and induce mesenteric mesenchyme
What is multicystic dysplastic kidney due to?
Ureteric bud develops but fails to induce differentiation of mesenteric mesenchyme (results in nonfunctional kidney consisting of cysts and connective tissue)
What is Wilms’ Tumour a result of?
Proliferation of metanephric blastema
- Embryonic glomerular structures
What mutations are associated with Wilms’ Tumour?
WT1 (expressed in metanephric blastema/mesenchyme)
What is a uteropelvic junction obstruction due to?
Narrowing at proximal ureter at junction
What is the most common cause of single kidmey obstruction?
Ureteropelvic junction (UPJ) obstruction
What can POTTER sequence be caused by?
- Chronic placental insufficiency
- Autosomal recessive polycystic kidney disease
- Obstructive uropathy (e.g posterior urethral valves), bilateral renal agenesis)
