Renal Embryology

Question 1

Nephrogenic cord gives rise to (2)

Answer 1

Nephrons and ducts.

Question 2

Pronephros overview

Answer 2

Appears in week 4 and degenerates shortly after.
Rudimentary - no function.
Has a pronephric duct and pronephric tubule.

Question 3

Mesonephros overview

Answer 3

Appears late week 4 and is functional until week 11.

Has a mesonephric duct and mesonephric tubule.

Question 4

Mesonephric duct and tubule give rise to:

Answer 4

Male genitalia.

Question 5

Metanephros overview

Answer 5

Begins to develop in week 5.
Is functional and definitive.
Contains a ureteric bud and metanephrogenic blastema (mass) in the pelvis.

Question 6

Metanephrogenic blastema and ureteric bud give rise to:

Answer 6

The nephron and collecting system.

Question 7

Glomerulus is from:

Answer 7

Dorsal aorta

Question 8

Bowman’s capsule and mesonephric tubules are from:

Answer 8

IM

Question 9

How does the mesonephric duct induce nephrons in adjacent nephrogenic cords?

Answer 9

The MD and MV undergo reciprocal signaling which causes the MV to become the MT and meet with the MD. The MT continues to elongate and form around the glomerulus.

Question 10

Ureteric bud (metanephric duct) is an:

Answer 10

Outgrowth from mesonephric duct.

Question 11

Metanephric duct is derived from:

Answer 11

Nephrogenic cord.

Question 12

Ureteric bud gives rise to (5):

Answer 12

Ureter
Pelvis
Major calyces
Minor calyces
Collecting tubules
All from IM.

Question 13

Metanephric blastema gives rise to (5):

Answer 13

Renal vesicles
Bowman's capsule
Proximal CT
Distal CT
Loop of Henle
All from IM.

Question 14

Development of the collecting system

Answer 14

Ureteric bud contacts the metanephroc blastema and gives rise to the renal pelvis.
Ureteric bud bifurcates and branches and coalesces to form major, then minor calyces.

Question 15

Development of the nephron of the metanephros

Answer 15

Nephron originates as a vesicle within the blastemic mass surrounding the collecting duct.
After signaling, the vesicle elongates into a tube and the glomerulus forms at one end and the proximal end forms the proximal CT, Loop of Henle, and distal CT.

Question 16

Unilater renal agenesis

Answer 16

More common in males.
Usually asymptomatic due to one kidney becoming hypertrophied.
Suspected in infants with one umbilical a.

Question 17

BL renal agenesis

Answer 17

Associated w/ oligohydramnios (and therefore lung problems).

20% of Potter sequence pts have renal agenesis.

Question 18

Renal agenesis is due to:

Answer 18

Ureteric bud and/or metanephric blastema did not develop properly.

Question 19

Duplex kidney

Answer 19

2 ureters at each kidney.
Abnormal division of the ureteric bud.
Asymptomatic.

Question 20

Kidneys receive blood from:

Answer 20

Nearby arteries. Often the iliac as.

Question 21

Ascent of the kidney

Answer 21

They are at adult position at week 9.
Due to caudal growth of the embryo.
Rotate 90 degrees during ascent.

Question 22

Pelvic kidneys, horseshoe kidneys do not ascend due to:

Answer 22

Being blocked by vasculature.

Question 23

Autosomal recessive polycystic kidney disease

Answer 23

Mutation of PKDH1 gene.
Both kidneys contain many small cysts.
Renal insufficiency.
25% associated with pulmonary hypoplasia.

Question 24

Multicystic dyplastic kidney disease

Answer 24

Abn development of the renal system.
Usually only one kidney affected.
Fewer cysts than ARPKD.
Cysts are thought to be due to wide dilations of the Loop of Henle.

Question 25

Ureter is from (2):

Answer 25

Mesonephric and metanephric ducts.

Question 26

Bladder is from:

Answer 26

Hindgut endoderm, except for trigone which is mesoderm.

Question 27

In the adult, the ureter is only from:

Answer 27

Metanephric duct.

Question 28

Urorectal septum

Answer 28

Separates the urogenital system from the rectum at the cloaca.

Question 29

Development of the median umbilical ligament in adults

Answer 29

Allantois --> urachus --> median umbilical ligament.

Question 30

3 regions of the urogenital sinus

Answer 30

``` Vesicle part (bladder) Pelvis part (urethra (f) or prostatic and membranous urethra (m)) Phallic (lining of vaginal vestibule (f) or spongy urethra (m)) ```

Question 31

Urachal fistula

Answer 31

Opening from bladder to naval. | Urine can leak through the naval.

Question 32

Urachal sinus

Answer 32

Deep invagination of the naval. Small median umbilical ligament can be ruptured and can cause a urachal fistula, but is rare.

Question 33

Exstrophy of the bladder

Answer 33

Arises in week 4 from body folding. | Bladder exists outside of the abdomen.

Question 34

Epispadias

Answer 34

Small opening on the dorsal side of the penis. Urine can leak. Improper location of genital tubercles caudal to cloacal membrane.

Question 35

Adrenal medulla is from:

Answer 35

NC (Chromaffin cells).

Question 36

Adrenal capsule is from:

Answer 36

Mesonephric mesoderm (IM)

Question 37

Adrenal cortex is from:

Answer 37

Somatic mesoderm.

Question 38

First and second cellular wave give rise to:

Answer 38

1st - fetal cortex | 2nd - adult cortex

Question 39

Fetal cortex produces

Answer 39

Pituitary ACTH, glucocorticoids, estrogen precursors.