Embryology of the Urogenital Systems

Question 0

What does intermediate mesoderm separate from during folding and forms urogenital ridge?

Answer 0

From lateral and paraxial mesoderm

Question 1

What do urinary and genital systems develop from?

Answer 1

Intermediate mesoderm of trilaminar disc

Question 2

What forms pronephros?

Answer 2

Nonfunctional cervical nephrotomes

Question 3

When do nephrotomes transitory and regress?

Answer 3

By week 5

Question 4

When does a second primitive kidney develop?

Answer 4

During the 4th week

Question 5

What follows the development of the second primitive kidney during the 4th week?

Answer 5

1. functional glomeruli develops
2. mesonephric tubules form
3. mesonphric duct opens into cloaca

Question 6

mesonephros are present and functional during what weeks?

Answer 6

from weeks 6-10

Question 7

What happens to mesonephros after week 10?

Answer 7

It degenerates except for: the duct system or some vestigial structures

Question 8

What does the duct system that remains contributes to?

Answer 8

Part of the male genital system (ductus deferens)

Question 9

What part of the mesonephros remains after week 10 in females?

Answer 9

Some vestigial structures in the female

Question 10

What does renogenesis involve?

Answer 10

Involves a process of reciprocal induction, which is retinoic acid dependent

Question 11

What establishes a “renogenic” region within the intermediate mesoderm in the tail of the embryo?

Answer 11

The cranial-caudal patterning

Question 12

What is the renogenic mesoderm called?

Answer 12

Metanephric blastema

Question 13

What is the function of the metanephric blastema?

Answer 13

Secretes growth factors that induce growth of the ureteric bud from the caudal portion of the mesonephric duct

Question 14

When the Ureteric bud proliferates how does it respond?

Answer 14

By secreting growth factors that stimulates proliferation and then differentiation of the metanephric blastema

Question 15

What does the metanephric blastema differentiate into after stimulation from ureteric bud?

Answer 15

Into glomeruli and kidney tubules

Question 16

What may cause inhibition of ureteric bud growth and renal hypoplasia or agenesis?

Answer 16

Perturbations in any aspect of renogenesis events (mutations of either metanephric or ureteric factors or disruption of retinoic acid signaling)

Question 17

In contrast to inhibition of ureteric bud growth, what else can occur during renogenesis?

Answer 17

Duplication or over proliferation of structures

Question 18

When does blood plasma from glomerular capillaries begin to be filtered?

Answer 18

By week 10

Question 19

When urine is produced In utero, what is the primary function?

Answer 19

It is not to clear waste (placenta) but to supplement production of amniotic fluid

Question 20

What may indicate bilateral renal agenesis or urethral obstruction?

Answer 20

Oligohydramnios: insufficient amount of amniotic fluid

Question 21

Where are kidneys formed? Why do they move during development?

Answer 21

In the pelvis but ascend to lumbar region with progressive revascularization from common iliac and aorta

Question 22

What enters the kidney independently from the primary renal vessels?

Answer 22

Aberrant renal vessels

Question 23

Aberrant renal vessels entering the kidney occurs how often in the population? Where do the vessels originate?

Answer 23

These occur in approximately 10% of individuals and 98% arise from the abdominal aorta

Question 24

When do aberrant renal vessels cause a problem vs pose little issues?

Answer 24

Most enter the renal pelvis and pose little problems | Aberrant renal arteries that enter the upper or lower poles of the kidney may post problems

Question 25

Aberrant arteries to the inferior pole of the kidney (4-6%) may be the cause for what?

Answer 25

Obstruction of the ureter and may cause an intermittent or continuous obstruction to urinary drainage from the renal pelvis

Question 26

When can potter syndrome be diagnosed?

Answer 26

In utero diagnosis

Question 27

Who is the first to survive Potter's syndrome diagnosis?

Answer 27

Abigail who now undergoes nightly dialysis prior to transplant. She went through experimental treatment, which involved intrauterine fluid injections to facilitate growth and development

Question 28

What prevents normal renal rotation?

Answer 28

Renal fusion

Question 29

What kind of blood supply do renal fusion usually have?

Answer 29

Abnormal blood supply usually from middle sacral or common iliac arteries

Question 30

What may also be crossed with/without fusion?

Answer 30

Ectopic kidney

Question 31

Pelvic kidney and horseshoe kidney are examples of _____

Answer 31

Renal fusion

Question 32

What type of renal fusion is most common?

Answer 32

Horseshoe kidney 90% fused at lower pole Usually found inferior to inferior mesenteric artery

Question 33

What is Wilms' tumor?

Answer 33

Cancer of the kidney

Question 34

Wilms' tumor usually affects who?

Answer 34

Children under the age of 5

Question 35

What causes Wilms' tumor?

Answer 35

Mutation in the WT1 gene

Question 36

3 month-old previously healthy boy presented with hematuria. A renal ultrasound, and subsequent chest, abdomen, and pelvis CT exam demonstrated a large heterogeneous right renal mass: diagnosis?

Answer 36

Wilms' tumor

Question 37

Describe the steps of the urinary bladder

Answer 37

1. cloaca divided by the urorectal septum 2. Dorsal (inferior) portion develops into the rectum and anal canal 3. The ventral (superior) portion develops into the bladder and urogenital sinus

Question 38

What does the bladder and urogenital sinus give rise to?

Answer 38

The bladder and lower urogenital tracts

Question 39

What bladder and urogenital tracts are present in males?

Answer 39

Prosstatic and penile urethrae

Question 40

What bladder and lower urogenital tracts are present in females?

Answer 40

Urethra and lower vagina

Question 41

Mesonephric duct and ureteric bud incorporation into posterior wall of urinary bladder occurs between what weeks?

Answer 41

4-6

Question 42

What do ureteric buds open into?

Answer 42

The bladder wall

Question 43

Where does the mesonephric ducts open?

Answer 43

More inferiorly into the pelvic urethra.

Question 44

What does not open into the bladder?

Answer 44

Ductus deferens

Question 45

What does the triangular region of the incorporated mesonephric duct incorporated in the bladder wall form?

Answer 45

The trigone

Question 46

Bladder is continuous (superiorly/inferiorly) with allantois?

Answer 46

Superiolry

Question 47

What should happen with the allantois?

Answer 47

Collapse and become the urachus

Question 48

What abnormalities can happen with the urachus?

Answer 48

1. may remain paten throughout its length: urachal fistula 2. patent only at an end: urachal sinus 3. remnants of urachal lumen may also give rise to urachal cysts: usually present as an abdominal mass

Question 49

When is the genotype of the embryo established?

Answer 49

At fertilization

Question 50

How long does the embryo remain in undifferentiated state?

Answer 50

Week 1-6

Question 51

When does phenotypic sexual differentiation begin?

Answer 51

Week 7

Question 52

When can male and female external genitalia be recognized?

Answer 52

Week 12

Question 53

When is the phenotypic differentiation complete?

Answer 53

Week 20

Question 54

Fetal sex is encoded where?

Answer 54

On the sex determining region of the Y chromosome (SRY)

Question 55

What triggers male development?

Answer 55

Synthesis of SRY protein (testis-determining factor, TDF)

Question 56

If SRY protein is not expressed what happens?

Answer 56

whether absent or defective, female path is followed

Question 57

What is the basic (default) developmental pathway?

Answer 57

Female

Question 58

What cannot be expressed in order for female path to be followed?

Answer 58

TDF

Question 59

Describe the male development pathway

Answer 59

1. activation of SRY gene 2. TDF 3. Differentiation of biopotential gonad into testis 4. Sertoli cell differentiation 5. Mullerian inhibitory substance/factor 6. regression of paramesonephric (mullerian) ducts 7. urogenital sinus, forrmed from division of the cloaca

Question 60

How many pairs of genital ducts are present in both sexes during development?

Answer 60

two

Question 61

When are both pairs of genital ducts present during development?

Answer 61

The indifferent stage

Question 62

Mesonephric ducts play the most important role in (male/female)

Answer 62

male

Question 63

Paramesonephric ducts play the most important role in (male/female)

Answer 63

female

Question 64

The gonads develop from what three tissues?

Answer 64

epithelium of intraembryonic coelom intermediate mesoderm primordial germ cells

Question 65

What invades the dorsal mesentery and migrate to urogenital ridges?

Answer 65

primordial germ cells from mesoderm of yolk sac

Question 66

What are aggregates of supporting cells (homorne secreting cells)?

Answer 66

Primary sex cords

Question 67

When primary sex cords develop what doe gonads now have?

Answer 67

An outer cortex and inner medulla

Question 68

What does the phallus become?

Answer 68

Clitoris or penis

Question 69

What do (uro)genital folds become?

Answer 69

Labis minora or shaft of the penis

Question 70

What does the labioscrotal (genital) wellings become?

Answer 70

Either labis majora or scrotum

Question 71

What are some paramesonephric duct anomalies?

Answer 71

1. uterus didelphys with double vagina 2. Uterus arcuatus 3. Uterus bicornis 4. Uterus bicorni unicollis: 1 redimentary horn 5. Atresia of cervix 6. Atresia of vagina

Question 72

What can result in cervical or vaginal atresia?

Answer 72

Partial or total atresia of the distal portion of both ductus

Question 73

What can have persistence of paramesonephric ductus if the circulating levels of AMH are low or there is an abnormal response to normal AMH?

Answer 73

46, XY

Question 74

Failure of the paramesonephric ducts to develop can result in what?

Answer 74

Missing uterine tubes, uterus and variable malformations of the upper portion of the vagina

Question 75

What is MRKH or Mayer-Rokitansky-Kuster-Hauser-Syndrome?

Answer 75

Missing uterine tubes, uterus and variable malformations of the upper portion of the vagina

Question 76

What is hypospadias?

Answer 76

incomplete fusion of the urethral folds

Question 77

where does the urethra open onto in males in hypospadias?

Answer 77

The ventral aspect of the penis

Question 78

What can hypospadias result from?

Answer 78

From inadequate androgen production or inadequate receptor sites for DHT

Question 79

What are the types of hypospadias from moderate to severe?

Answer 79

1. glandular 2. penile 3. penoscrotal 4. perineal

Question 80

What do females (46, XX) with severe forms of adrenal hyperplasia have what?

Answer 80

Ambiguous genitalia at birth due to excess adrenal androgen production in utero Female intersex

Question 81

What does abiguous genitalia range from?

Answer 81

Ranges from complete fusion of the labioscrotal folds and a phallic urethra to only clitoromegaly, partial fusion of the labioscrotal folds, or both

Question 82

Do intersex females have ovaries?

Answer 82

there are no abnormalities of ovaries

Question 83

What is androgen insensitivity syndrome (AIS) - complete ?

Answer 83

An x-linked disorder in which receptors remain unresponsive to androgens Despite normal levels of testosterone, the male fetus fails to masculinise External genitalia are feminine: internally they posses non-functional undescended testes Some males may tend to be feminine in gender and behaviour (maybe)

Question 84

What can happen at puberty with someone with AIS?

Answer 84

Secondary female sexual characteristics may appear due to estradiol from testosterone aromatization

Question 85

What is common to perform on males with AIS?

Answer 85

gonadectomies at puberty and for them to receive hormone therapy, to be reared as female

Question 86

The degree of feminization of AIS depends on what?

Answer 86

Upon affected androgens and the amount of residua receptor function

Question 87

What is 5-ARD?

Answer 87

Autosomal recessive condition resulting in the inability to convert testosterone to the more physiologically active dihydrotestosterone (DHT)

Question 88

If someone has 5-ARD what happens?

Answer 88

Because DHT is required for the normal masculinization of the external genitalia in utero, genetic males with 5-ARD are born with ambiguous genitalia (underdevelopment of penis and scrotum or psuedovaginal perineoscrotal hypspadias)

Question 89

What is 5-ARD often misdiagnosed as?

Answer 89

AIS

Question 90

What derivatives are normal in 5-ARD?

Answer 90

Derivatives of mesonephric duct are normal

Question 91

What is the third gender called?

Answer 91

Guevedoche or Machinhembras | first woman, then man