Session 3: Case Studies

Question 1

Is the kidney derived from paraxial mesoderm? Explain

Answer 1

No, it’s derived from intermediate mesoderm.

Question 2

The region of mesoderm that gives rise to the kidney is medial to the lateral plate mesoderm?

Answer 2

Yes

Question 3

Do the metanephric kidneys never produce urine during intrauterine life?

Answer 3

Yes that is true. The embryonic kidneys starts to produce urine around week 10 when the metanephros has fully developed.

Question 4

Do the ureters empty into the bladder via the mesonephric ducts from which they are derived as the ureteric bud?

Answer 4

No, ureteric bud is derived from the mesonephric ducts.

Question 5

The hindgut does not contribute to the development of the urinary system?

Answer 5

False
The hindgut’s caudal end known as the cloaca and therefore the urogenital sinus. Here the urorectal septum separate the cloaca into urogenital sinus and anorectal canal.

Question 6

Interaction between which structures is key to development of the definitive kidney. A defect in which of these might underlie renal agenesis?

Answer 6

When the ureteric bud fails to interact with the metanephros (intermediate mesoderm)

Question 7

Explain the failure of a kidney to ascend to its final destination.

Answer 7

When craniocaudal shift doesn’t work. This is associated with mullerian dysgenesis and also when arteries might be in the way like the inferior mesenteric artery.

Question 8

Explain why a horseshoe kidney fail to ascend properly.

Answer 8

Because it gets stuck under the inferior mesenteric artery.

Question 9

Explain why a kidney might have supernumerary renal arteries.

Answer 9

Because as the kidneys ascend they will continuously receive new arteries and old arteries are suppose to degenerate. The arteries may however fail to degenerate.

Question 10

What is the significance of the facts that accessory renal arteries are terminal/end arteries?

Answer 10

Terminal arteries do not have anastomoses so if that artery stops working then that area of the kidney will die.

Question 11

Ectopic ureteral orifices frequently open inferior to the bladder. Why might this patient complain of urinary incontinence?

Answer 11

If the opening is distal to the EUS it means that there can be constant drippage as the EUS is the sphincter holding urine in place.