Development Of The Urinary Tract

Question 1

The kidney forms from 3 separate systems, which develop sequentially after the previous one has disappeared.

Where does the first system appear and what is it called?

Name the next 2 systems

Answer 1

Cervical region

The Pronephros followed by Mesonephros then Metanephros

Question 2

Describe the Pronephros stage (never functions in humans)

Answer 2

Pronephritic duct extends from cervical region to Cloaca and drives development of next stage/ system (Mesonephros)

Question 3

Which duct arises from the Pronephritic duct?

Answer 3

Mesonephric duct

Question 4

Describe the Mesonephros stage

Answer 4

• Mesnonephric tubules develop caudal to Pronephric region

- Mesoneohric tubules + mesnonephric duct make up the embryonic kidney

Question 5

What does the Mesonephric Duct sprout?

What does this do?

Answer 5

Sprouts the Ureteric Bud, which induces development of the Definitive/ True Kidney (originally the metanephric blastema)

(UB: Undifferentiated intermediated mesoderm, caudal to mesonephros)

Question 6

Where does the Metanephric kidney first appear before moving upwards?

Answer 6

Pelvic region

Question 7

What is Renal Agenesis?

Answer 7

Failure of ureteric bud to interact with intermediate mesoderm (No true kidney formed)

Question 8

Suggest 5 things that can go wrong in urinary tract development

Answer 8

• Renal agenesis
• Migration abnormality (of gonads and kidneys)
• Duplication defects
• Ectopic ureter
• Cystic disease

Question 9

Suggest 2 structural abnormalities related to migration

Answer 9

• Pelvic kidney (Kidneys don’t ascend)

- Horseshoe kidney (Caudal poles of kidneys fuse during ascending )

Question 10

How are the Urinary and reproductive tracts separated from the GI tract?

Answer 10

Urorectal septum descends to separate Cloaca into Rectum and Urogenital Sinus

Question 11

Outline the development of the Urogenital Sinus

Answer 11

• Superior part connects to Umbilicus (Urachus)
• Majority Differentiates to form bladder
• Inferior part develops into Urethra

Question 12

What are the 4 parts of the male urethra?

Answer 12

• Pre-prostatic
• Prostatic
• Membranous
• Spongy (formed by Genital Tubercle elongation and Genital Fold fusion)

Question 13

What is Hypospadias?

Answer 13

Defect in fusion of genital folds

Question 14

What causes ectopic/ duplex ureter?

Answer 14

Splitting of ureteric bud so that there’s an extra bud which develops into an extra ureter

Question 15

What is the derivative of the Median Umbilical Ligament?

Connects bladder to umbilicus

Answer 15

The Urachus