Lecture 10: Renal Embryology

Question 1

Kidneys and gonads are derived from what kind of mesoderm?

Answer 1

Intermediate mesoderm

Question 2

What is the urogenital ridge?

Answer 2

Longitudinal band of mesoderm that forms on each side of dorsal aorta

Question 3

What does the urogenital ridge give rise to?

Answer 3

Nephrogenic cord

Question 4

What does the nephrogenic cord give rise to?

Answer 4

Pronephros
Mesonephros
Metanephros

Question 5

Describe the pronephros.

Answer 5

Appears early in 4th week in cervical region

• ducts run caudally into cloaca
• degenerates pretty quickly but ducts remain

Question 6

Describe the mesonephros.

Answer 6

Appears late in 4th week

• ducts develop early from pronephros ducts
• induce tubule from surrounding intermediate mesoderm
• produces urine
• has glomerulus and Bowman’s capsule
• degenerates by 12th week

Question 7

In males, what does the mesonephros become?

Answer 7

Efferent ductules

Question 8

Describe the metanephros.

Answer 8

Appears during 5th week and functional by 9th-10th week

• ureteric bud: from mesonephric duct and branches into sacral part of intermediate mesoderm
• metanephric blastema: from nephrogenic cord

Question 9

What is the purpose of fetal kidneys?

Answer 9

Amniotic fluid production

Question 10

How does the renal pelvis form?

Answer 10

Ureteric bud elongates and penetrates metanephric blastema

Question 11

What gives rise to the ureter?

Answer 11

Stalk of ureteric bud

Question 12

How do collecting tubules form?

Answer 12

Cranial part of ureteric bud continues to branch

-major and minor calyces

Question 13

What do ureteric buds give rise to?

Answer 13

Ureter
Renal Pelvis
Major and minor calyces
Collecting ducts

Question 14

What does the metanephric blastema give rise to?

Answer 14

Bowman’s Capsule
Proximal and Distal Convoluted Tubules
Loop of Henle

Question 15

How do nephrons form?

Answer 15

1) Metanephric blastema can bud off and give rise to metanephric vesicles
2) Vesicles form metanephric tubules
3) Proximal end will form glomerular capsule
4) Tubule differentiates into PCT, DCT, and nephron loop

Question 16

In what direction does the renal hilum rotate?

Answer 16

Medially by 90 deg

Question 17

Where do renal arteries originally branch from?

Answer 17

Common Iliac Artery

Question 18

What is renal agenesis?

Answer 18

Failure of development of kidney(s)

Question 19

What is an incomplete division of the ureter?

Answer 19

Kidney has 2 ureters that eventually join later and make on single ureter

Question 20

What is a complete division of the ureter?

Answer 20

Kidney has 2 ureters that do not join and remain separate until bladder

Question 21

What is a horseshoe kidney?

Answer 21

Kidneys fused together at inferior poles

-low lying

Question 22

What happens if there are extra renal vessels?

Answer 22

Multiple renal arteries that can potentially obstruct the ureter

Question 23

What is multicystic dysplastic kidney disease?

Answer 23

Malformation of the kidney during fetal development

-irregular cysts of varying sizes from loop of henle

Question 24

What is the difference between polycystic and multicystic kidney disease?

Answer 24

Polycystic: normally affects both kidneys
Multicystic: normally one kidney

Question 25

What are the three parts of the urogenital sinus?

Answer 25

1) Vesical part: most of bladder 2) Pelvic part: neck of bladder 3) Phallic part: spongy urethra in males and lining of vaginal vestibule in females

Question 26

How is trigone formed?

Answer 26

1) Mesonephric duct incorporated in posterior wall of bladder 2) Ureteric bud attaches, connecting openings of buds into bladder wall 3) Mesonephric duct opening carried inferiorly to pelvic urethra *Trigone is blending of mesonephric and ureteric ducts

Question 27

What type of mesoderm is found in trigone?

Answer 27

Intermediate mesoderm

Question 28

What type of mesoderm is found in submucosa and muscles of bladder?

Answer 28

Splanchnic mesoderm

Question 29

What is bladder continuous with?

Answer 29

Allantois --> urachus

Question 30

How is medial umbilical ligament formed?

Answer 30

Urachus extends from apex of bladder to umbilicus forming ligament

Question 31

What is exstrophy of the bladder?

Answer 31

Congenital abnormality: skin over the lower abdominal wall does not form properly - posterior wall of bladder is open and exposed on the outside of abdomen - defective closure of ventral abdominal wall

Question 32

What is epispadias?

Answer 32

Urethral opening is on dorsum rather than ventral side of genital tubercle

Question 33

What are urachal cysts?

Answer 33

Remnants of epithelial lining of urachus that can become infected and enlarged

Question 34

What is an urachal sinus?

Answer 34

End of urachus remains open into bladder or umbilicus

Question 35

What is an urachal fistula?

Answer 35

Entire urachus remains patent and allows urine to escape from umbilical orifice

Question 36

From what cells are suprarenal glands derived from?

Answer 36

Neural Crest Cells