Renal Embryology

Question 1

The kidneys of a 4-week-old human embryo are examined. The development of which structure is expected to be seen?


Answer 1

The pronephros


Question 2

After week 4, what happens to the pronephros?


Answer 2

The pronephros degenerates


Question 3

During which trimester of fetal development does a structure that eventually contributes to the male genital system arise?


Answer 3

During the first trimester, the mesonephros, which later contributes to male genital system, begins to develop


Question 4

What fetal structure functions as the interim kidney for the first trimester?


Answer 4

Mesonephros


Question 5

A researcher wishes to physically block development of the ureteric bud. Where must he stall development?


Answer 5

The caudal end of the mesonephros


Question 6

What adult structures in the urinary tract are derived from the ureteric bud?


Answer 6

Collecting ducts, calyces, pelvises, and ureters


Question 7

What adult structures in the urinary tract are derived from the metanephric mesenchyme?


Answer 7

Structures in the kidney, from the glomerulus to the distal convoluted tubule


Question 8

What is the most common cause of hydronephrosis in a fetus? Why?


Answer 8

Ureteropelvic junction obstruction; the ureteropelvic junction is the last structure to canalize


Question 9

The interaction of which two structures/tissues in the developing kidney induces proper differentiation and formation of the renal tubules?


Answer 9

Ureteric bud and metanephric mesenchyme (aberrant interaction leads to congenital malformations)


Question 10

The ____ (pronephros/mesonephros/metanephros) appears at week 5 of gestation and is permanent.


Answer 10

Metanephros


Question 11

After formation of the ____, nephrogenesis continues through weeks 32–36 of gestation.


Answer 11

Metanephros

Question 12

A newborn is found to have bilateral renal agenesis, which leads to the Potter sequence (syndrome). What else causes this sequence to occur?


Answer 12

Autosomal recessive polycystic kidney disease (ARPKD), obstructive uropathy (e.g., posterior urethral valves)


Question 13

How does the mnemonic POTTER help you remember the characteristic features of the Potter sequence (syndrome)?


Answer 13

Pulmonary hypoplasia, Oligohydramnios (trigger), Twisted face, Twisted skin, Extremity defects, Renal failure (in utero)


Question 14

A fetus has pulmonary hypoplasia, facial and limb deformities, and bilateral renal agenesis. What syndrome is this?


Answer 14

Potter sequence (syndrome)

Question 15

A 40-year-old man is incidentally found to have fused kidneys on an abdominal CT scan. Name this anatomic abnormality.


Answer 15

Horseshoe kidney


Question 16

The horseshoe kidney gets trapped beneath the ____ artery.


Answer 16

Inferior mesenteric (and it remains low in the abdomen)


Question 17

A girl with a webbed neck, short stature, and a low hairline presents with amenorrhea. What renal anomaly might be found on ultrasound?


Answer 17

Horseshoe kidney (this is Turner syndrome)


Question 18

Name the group of congenital syndromes with which horseshoe kidney is most strongly associated.


Answer 18

Chromosomal aneuploidy syndromes (e.g., Down, Edwards, Patau, Turner)

Question 19

During development, an abnormal interaction between an embryo’s ureteric bud and the metanephric mesoderm occurs, Is the kidney functional?


Answer 19

No—this interaction results in a multicystic dysplastic kidney, a nonfunctional kidney consisting of connective tissue and cysts)


Question 20

Is multicystic dysplastic kidney usually unilateral or bilateral? What are the symptoms and how is the condition diagnosed?


Answer 20

Unilateral; generally asymptomatic, with hypertrophy (compensation) by the other kidney; diagnosed prenatally with ultrasound

Question 21

To what anomaly does bifurcation of the uteric bud before it enters the metanephric blastema lead?


Answer 21

Duplex collecting system


Question 22

A 4-year-old has vesicoureteral reflux and multiple UTIs because of asynchronous muscle contraction. What is the developmental pathogenesis?


Answer 22

Duplex collecting system caused by bifurcation of the ureteric bud before it enters the metanephric blastema, result in a bifid ureter