Urinary Embryology

Question 2

Hiow many kidney systems develop originally in embryology?

Answer 2

3 sequentially

Disappearance of one system marks the onset of development of the next stage

First appears in the cervical region - pronephros

Question 3

What are the 3 developmental systems of the kidney?

Answer 3

Pronephros

Mesonephros

Metanephros

Question 4

What is a nephrotome?

Answer 4

Section of mesoderm giving rise to the pronephros and eventually the rest of the kidneys

Question 5

Why is the pronephros important?

Answer 5

Never functions in humans but has a duct - pronephric duct extends from the cervical region to the cloaca and drives the development of the next developmental stage

Question 6

What is the urogential ridgef?

Answer 6

Region of intermediate mesoderm giving rise to both embryonic kidney and the gonad

Question 7

Where do the mesonephric tubules form?

Answer 7

Caudal to the pronephric region

Question 8

What constitutes the embryonic kidney?

Answer 8

Mesonephric tubules and the mesonephric duct

Question 9

What is the importance of the mesonephros?

Answer 9

Duct sprouts the ureteric bud which induces development of the definitive kidney which has an important role in the development of the reproductive system in the male

Question 10

What is the metanephric blastema?

Answer 10

Gives rise to the true kidney from the ureteric bud

Question 11

How does teh ureteric bud change during development of the kidney?

Answer 11

Contacts metanephric blastema

Bud expands and branches

forms calices

Question 12

What forms the collecting system of the kidney?

Answer 12

Ureteric bud

Question 13

What developmental structure forms the excretory component of the kidney?

Answer 13

Intermediate mesoderm under the influence of the ureteric bud

Question 14

Describe the “ascent” of the kidney.

Answer 14

Metanephric kidney first appears in the pelvic region

Undergoes an apparent caudal to cranial shift, crossing the arterial fork formed by vessels returning blood from the fetus to the placenta

Question 15

What happens if the ureteric bud fails to interact with intermediate mesoderm?

Answer 15

Renal agenisis - can survive if only one side

Question 16

What is wilm’s tumour?

Answer 16

Paediatric tumour of the kidney

Question 17

What are ectopic ureters?

Answer 17

ureter openings in the wrong place eg. vagina.

Symptoms - incontinence

Question 18

How do duplication defects of the kidney come about?

Answer 18

Splitting of the ureteric bud - partial or complete. Symptomatic consequence is ectopic ureteral opening causing incontinence

Question 19

What does multicystic kidney disease cause?

Answer 19

Atresia of ureter

Question 20

What is the cloaca?

Answer 20

The end of the gastrointestinal, urinary and reproductive tracts.

Question 21

What is the urogenital sinus created from?

Answer 21

Hindgut by urorectal septum. continuous with umbilicus

Question 22

Describe the urogenital sinus.

Answer 22

3 parts -

Largest - future bladder

Pelvic and phallic - parts of future urethra

Question 23

What doe shte female urethra form from?

Answer 23

Urogenital sinus

Question 24

What does the male urethra form from?

Answer 24

Pelvic part of urogenital sinus forms the pre-prostatic, prostatic and membranous parts nad the phallic part forms the spongy length of the urethra

Question 25

How is the different male/female external genitalia formed?

Answer 25

In the male, the genital tubercle elongates and genital folds fuse to form the spongy urethra

No fusion occurs inthe female and the urethra opens into the vestibule

Question 26

What is hypospadias?

Answer 26

Defect in fusion of urethral folds

Urethra opens onto the ventral surface rather than at the end of the glans