Urinary development

Question 1

Name the 3 sets of excretory organs which contribute to the development of the urinary system:

Answer 1

1) Pronephros
2) Mesonephros
3) Metanephros

Question 2

During which week after fertilisation does the pronephros develop? What is the function of the pronephros?

Answer 2

Week 4

Makes duct, which makes contact with the hind gut (no kidney-like function)

Question 3

During which week after fertilisation does the mesonephros develop? When does it regress?

Answer 3

Week 4 (end of)
Regresses in week 8

Question 4

From which germ layer does the kidneys and ureters develop from?

Answer 4

Mesoderm (intermediate)

Question 5

What is the function of the mesonephros?

Answer 5

• Forms mesonephric tubules
• Forms mesonephric duct, which sprouts the ureteric bud, and is important for the development of the ductal male reproductive system

Question 6

During which week after fertilisation does the metanephros develop?

Answer 6

Week 5

Question 7

What is the function of the ureteric bud? From which developing excretory organ does it sprout?

Answer 7

• Contacts metanephric blastema, initiates development of collecting system (ureter, renal pelvis, calyces, papillary and collecting ducts)
• Mesonephros

Question 8

List the parts of the urinary collecting system:

Answer 8

• Renal pelvis
• Ureter
• Calyces
• Papillary ducts
• Collecting ducts

Question 9

List the parts of the urinary excretory system:

Answer 9

• Glomerulus
• Bowman’s capsule
• Proximal Convoluted Tubule
• Loop of Henle
• Distal Convoluted Tubule

Question 10

What does the urinary collecting system develop from?

Answer 10

Ureteric bud (from the mesonephros)

Question 11

What does the urinary excretory system develop from?

Answer 11

Metanephric cap (metanephros)

Question 12

Describe the ascent of the kidneys. What causes this process to occur?

Answer 12

• Cranio-caudal shift from L4 -> T12/L1
• Lateral displacement
• 90’ rotation

Migration and expansion of the caudal region of the embryo

Question 13

Why do some people have accessory renal vessels?

Answer 13

• Failure of some vessels to regress during the ascent of the kidneys in embryonic development

Question 14

From which germ layer does the urinary bladder and urethra develop?

Answer 14

Endoderm (hindgut derivative)

Question 15

What is the name of the tissue which grows between the urogenital sinus and anorectal canal, separating the tubes?

Answer 15

Urorectal septum

Question 16

What is the fate of the urachus?

Answer 16

Median umbilical ligament

Connects apex of bladder to umbilicus

Question 17

Name the 3 parts of the urogenital sinus:

Answer 17

1) Bladder part
2) Pelvic part
3) Phallic part

Question 18

What is the difference in the mesonephric duct development between males and females?

Answer 18

Males - Mesonephric ducts make openings in pelvic part of the urogenital sinus = future vas deferens and prostate
Females - mesonephric ducts regress

Question 19

From which part of the urogenital sinus does the female urethra develop from?

Answer 19

Pelvic part

Question 20

From which part of the urogenital sinus does the male urethra develop from?

Answer 20

• Pre-prostatic, prostatic and membranous urethra forms from the pelvic part
• Spongy urethra forms from phallic part

Question 21

Name the 4 sections of the male urethra:

Answer 21

1) Pre-prostatic
2) Prostatic
3) Membranous
4) Spongy

Question 22

If the ureteric bud fails to interact with the intermediate mesoderm, which congenital defect will result?

Answer 22

Renal agenesis

Question 23

If pregnant women presents with abnormally low amniotic fluid volume, which congenital defect is likely to be present?

Answer 23

Bilateral renal agenesis

Question 24

How would bilateral renal agenesis present during pregnancy?

Answer 24

Abnormally low amniotic fluid volume

Question 25

Name the tumour of the metanephric blastema, a childhood cancer:

Answer 25

Wilm’s tumour

Question 26

What is the typical presentation of Wilm’s tumour?

Answer 26

Child ~2/3 yrs
Painless swollen abdomen
Haematuria
Hypertension
Weight loss

Question 27

What development event causes a bifid renal pelvis or bifid ureter?

Answer 27

Splitting of the ureteric bud

Question 28

What is the outcome if the ureteric bud splits during development?

Answer 28

Either:

• Bifid renal pelvis
• Bifid ureter

Question 29

Name the 2 main types of cystic kidney disease:

Answer 29

• Multicystic dysplastic kidney

- Polycystic Kidney Dease (inherited)

Question 30

What is exstrophy of the bladder? How does it occur?

Answer 30

‘Inside out’ bladder

Due to rupture of cloacal membrane = lower abdo wall doesn’t form properly = open, exposed bladder

Question 31

What is the name of the congenital defect where the urethra opens onto the ventral surface rather than at the end of the glans? How does this occur?

Answer 31

Hypospadias

Defective fusion of urethral folds

Question 32

What is hypospadias?

Answer 32

Congenital defect where the urethra opens onto the ventral surface rather than at the end of the glans

Question 33

Why is a horseshoe kidney always located at the pelvic brim?

Answer 33

Kidneys fuse before ascent

During ascent the fused kidney catches on the IMA, preventing further ascent