Lecture 37: Urinary System Development

Question 1

Which embryonic kidneys are the first to develop?

Answer 1

Pronephric kidneys

Question 2

From what germ layer do the pronephric kidneys differentiate from?

Answer 2

Intermediate mesoderm

Question 3

Which embryonic kidneys are non-functional in mammals, but required for the rest of the excretory system to develop?

Answer 3

Pronephros

Question 4

What is the role of retinoic acid in the induction of the pronephric ducts?

Answer 4

Sets expression limits of genes

Question 5

What is the role of Hox4-11 genes in the induction of the pronephric ducts?

Answer 5

Determines craniocaudal limits of early urinary system

Question 6

What is induced by transcription factors Pax-2 and Pax-8 during induction of pronephric ducts?

Answer 6

Lim-1

Question 7

What is the result of Lim-1 acting on intermediate mesoderm during pronephric duct induction?

Answer 7

Causes aggregation of mesenchymal cells in intermediate mesoderm into pronephric ducts

Question 8

What embryonic kidney begins formation of the functional kidney in most vertebrate embryos (including humans)?

Answer 8

Mesonephros

Question 9

How do the mesonephric tubules differ physically from the pronephric tubules?

Answer 9

Mesonephric tubules are longer and sigmoid in shape.

Question 10

What forms from the mesonephric duct?

Answer 10

Ureteric bud/metanephric diverticulum

Question 11

What does the metanephric diverticulum give rise to?

Answer 11

Adult ureter, renal pelvis, collecting tubules

Question 12

What forms from the metanephrogenic blastemata?

Answer 12

Renal tubules of adult kidney

Question 13

Explain the relationship between development of metanephrogenic blastema and ureteric diverticula?

Answer 13

Neither one can develop in absence of the other (reciprocal inductive effects)

Question 14

Uroplakins

Answer 14

Make ureter epithelium impermeable to water

Question 15

What is the function of Slit-2/Robo-2 with respect to the ureteric bud outgrowth?

Answer 15

Represses GDNF in anterior regions, thus keeping ureteric bud in posterior location

Question 16

Name the urinary sistem anomaly that can be caused by renal agenesis and oligohydramnios. This anamoly results in flattened face/ears, tapering fingers, pulmonary hypoplasia and is usually incompatible with life.

Answer 16

Potter Sequence

Question 17

Horseshoe kidney

Answer 17

Kidneys fused at inferior poles; usually asymptomatic but may cause positional abnormalities of other organs

Question 18

Polycystic kidney disease

Answer 18

Many cysts present in parenchyma of kidney; due to mutations in PKD1/PKD2 which make proteins polycystin1/polycystin2

Question 19

Extrophy of Bladder

Answer 19

Urinary bladder opens broadly into abdominal wall; may involve phallus in males (epispadias). May be due to reduction in Shh.