Embryology of the Urogenital System

Question 1

The urinary (and genital) system develops from what?

Answer 1

mesoderm of trilaminar disc

Question 2

Intermediate mesoderm separates from lateral and paraxial mesoderm during folding and forms what?

Answer 2

urogenital ridge

Question 3

In regards to mesonephros, during the 4th week, what develops?

Answer 3

A second primitive kidney; functional glomeruli; mesonephric tubules; and mesonephric duct opens into cloaca

Question 4

Mesonephros are present and functional from week ___ to week ___

Answer 4

6-10

Question 5

After week 10, mesonephros degenerates except for:

Answer 5

the duct system - contributes to part of the male genital system
some vestigial structures in the female

Question 6

Steps in Renogenesis involve a process of reciprocal induction, which is ___ ___ dependent

Answer 6

retinoic acid

Question 7

In regards to Renogenesis, what type of patterning establishes a “renogenic” region within th intermediate mesoderm in the tail of the embryo?

Answer 7

cranial-caudal

Question 8

The renogenic mesoderm is the ___ ___

Answer 8

metanephric blastem

Question 9

In Renogenesis, the metanephric blastema secretes growth factors that include growth factors that induce growth of the ___ ___ from the caudal portion of the mesonephric duct

Answer 9

ureteric bud

Question 10

In renogenesis, the ureteric bud proliferates and responds by secreting growth factors that stimulates proliferation and then differentiation of the metanephric blastema into what?

Answer 10

glomeruli and kidney tubules

Question 11

In renogenesis, pertuberations in any aspects of inductive events may cause what?

Answer 11

inhibition of ureteric bud growth and renal hypoplasia or agenesis

Question 12

List uteric bud derivatives in order that they develop

Answer 12

collecting tubules/ducts -> minor calyces -> major calyces -> renal pelvis -> ureters

Question 13

Blood plasma from glomerular capillaries begins to be filtered by what week?

Answer 13

10

Question 14

Urine is produced but the primary function is not to clear waste. What is the primary function at this time?

Answer 14

supplement production of amniotic fluid

Question 15

What is oligohydraminos?

Answer 15

insufficient amount of amniotic fluid

Question 16

What indicates bilateral renal agenesis or urethral obstruction?

Answer 16

oligohydraminos

Question 17

Kidneys are formed in pelvis but ascend to lumbar region with progressive revascularization from which two sources?

Answer 17

common iliac & aorta

Question 18

Aberrant renal vessels enter the kidney independently from what?

Answer 18

primary renal vessels

Question 19

True or false?

Aberrant renal arteries that enter the upper or lower poles of the kidney may pose problems

Answer 19

true

Question 20

Aberrant arteries to the inferior pole of the kidney may be the cause of obstruction of the ureter and may cause what?

Answer 20

an intermittent or continous obstruction to urinary drainage from the renal pelvis

Question 21

Renal fusion prevents what?

Answer 21

normal rotation

Question 22

Renal fusion causes abnormal blood supply in what area?

Answer 22

usually from middle sacral or common iliac arteries

Question 23

What is the name of the most common fused kidney?

Answer 23

horseshoe kidney

Question 24

This type of renal tumor usually affects children under the age of 5 and is caused by mutations in the WT1 gene

Answer 24

Wilms’ tumor

Question 25

In regards to development of the urinary bladder, the cloaca is divided by what?

Answer 25

the urorectal septum

Question 26

The dorsal portion of the cloaca develops into what?

Answer 26

the rectum and anal canal

Question 27

The ventral portion of the cloaca develops into what?

Answer 27

the bladder and urogenital sinus which will give rise to the bladder and lower urogenital tracts

Question 28

The triangular region of the incorporated mesonephric duct incorporated in the bladder wall forms the ____

Answer 28

trigone

Question 29

What occurs during a urachal fistula

Answer 29

bladder is continuous superiorly with allantois

Question 30

Remnants of the tracheal lumen may give rise to urachal ___, which usually present as an abdominal mass

Answer 30

cysts

Question 31

The genotype of the embryo is established when?

Answer 31

at fertilization

Question 32

True or False? | From weeks 1-6, the embryo remains in an undifferentiated state

Answer 32

true

Question 33

Phenotypic sexual differentiation occurs at what week?

Answer 33

week 7

Question 34

male and female external genitalia can be recognized at what week?

Answer 34

week 12

Question 35

phenotypic differentiation is complete at what week?

Answer 35

week 20

Question 36

Fetal sex of male is encoded on which gene on the Y chromosome?

Answer 36

SRY

Question 37

Synthesis of SRY protein triggers what?

Answer 37

male development

Question 38

If SRY is not expressed, what occurs?

Answer 38

female development

Question 39

In regards to development of genital ducts, how many pairs of ducts are present in both sexes?

Answer 39

two

Question 40

Both pairs of ducts are present during what stage of development

Answer 40

indifferent stage

Question 41

In the male, which ducts play the most important role?

Answer 41

the mesonephric ducts

Question 42

In the female, which ducts play the most important role?

Answer 42

paramesonephric

Question 43

The gonads develop from what 3 tissues?

Answer 43

epithelium of intraembyronic coelom, intermediate mesoderm, and primordial germ cells

Question 44

Pimordial germ cells from mesoderm of yolk sac invade the dorsal mesentery and migrate where?

Answer 44

urogenital ridges

Question 45

What are aggregates of supporting cells (hormone secreting cells) of the gonads

Answer 45

primary sex cords

Question 46

In regards to external genitalia, what is the phallus in males and females?

Answer 46

males: penis females: clitoris

Question 47

In regards to external genitalia, what are the urogenital folds in males and females?

Answer 47

males: shaft of penis females: labis minoris

Question 48

In regards to external genitalia, what are the genital swellings in males and females?

Answer 48

males: scrotum females: labis majora

Question 49

In regards to internal ducts, partial or total atresia of distal portion of both ducts can result in what?

Answer 49

cervical or vaginal atresia

Question 50

46, XY can have a presistence of paramesonephric ducts if the circulating levels of ___ are low or there is an abnormal response to normal ___

Answer 50

AMH; AMH

Question 51

Failure of the paramesonephric ducts to develop occurs in

Answer 51

mullerian agenesis note: also called MRKH

Question 52

In regards to external genitalia, what is incomplete fusion of the urethral folds called?

Answer 52

hypospadias

Question 53

Females with severe adrenal hyperplasia have ambiguous genitalia at birth due to what?

Answer 53

excess adrenal androgen production in utero

Question 54

Name the following disorder: x-linked disorder in which receptors remain unresponsive to androgens; external genitalia are feminine but internally possess non-functioning testes; at puberty, secondary female sexual characteristics may appear due to estradiol from testosterone aromatizaiton

Answer 54

Androgen Insensitivity Syndrome

Question 55

Name this condition: autosomal recessive condition resulting in the inability to convert testosterone to the more physiologically active dihydrotestosterone; often misdiagnosed as AIS

Answer 55

5-alpha reductase deficiency