Yan Genital System

Question 1

When is sex determined?

Answer 1

at fertilization (presence or absence of Y chromosome)

Question 2

When does male/female morphology develop?

Answer 2

7th week

Question 3

What are genital (gonadal) ridges and what are they derived from?

Answer 3

the precursor to the genitals

epithelium and condensation of underlying mesenchyme

Question 4

When do germ cells appear on genital ridges?

Answer 4

at the 6th week

Question 5

Explain how the gonads begin to develop?

Answer 5

PGCs-> dorsal mesentery of the hindgut->primitive gonads-> invade gonadal ridges-> development

Question 6

Where do primordial germ cells originate and what are they?

Answer 6

endodermal cells in the wall of the yolk sac close to allantois

Question 7

How do the primordial germ cells migrate from the yolk sac to the dorsal mesentery of the hindgut?

Answer 7

by ameboid movement

Question 8

When do the PGCs arrive at the gonads?

Answer 8

at the beginning of 5th week

Question 9

When do the PGCs invade the gonadal ridges?

Answer 9

at 6th week

Question 10

If you don’t have PGCs will you get testes and ovaries?

Answer 10

NO, you need PGCs to induce the development of the testis or ovary

Question 11

What happens once the PGCs arrive at the genital rides?

Answer 11

Epithelium of genital ridges proliferate and penetrate underlying mesenchyme to turn into primitive sex cords

Question 12

When the PGCs arrive at the genital ridges and penetrate the underlying mesenchyme, it turns into the primitive sex cords. Are these sex cords of males or females?

Answer 12

neither, they are indifferent and can later turn into either or

Question 13

How do you make PGCs turn into testis?

Answer 13

PGCs will have a Y chromosome with SRY (TDF) gene that will make the primitive sex cords turn into testis and medullary cords. These medullary cords will then converge at the rete testis and are covered by tunica albuginea

Question 14

In the fourth month, testis cords are composed of (blank) and (blank) (derived from the surface epithelium. Somatic cell component)

Answer 14

PGCs and Sertoli cells

Question 15

Leydig cells, derived from the original mesenchyme of the gonadal ridges, lie between the (blank). Testosterone production starts at week 8.

Answer 15

testis cords

Question 16

(blank) is important for the development of the genital ducts and external genitalia.

Answer 16

Testosterone

Question 17

Testis cords remain solid until (blank)

Answer 17

puberty

Question 18

Explain what happens to the testis cords after puberty?

Answer 18

the cords undergo canalization (turn into canals) and become seminiferous tubules that join at the rete testis. These then connect to the efferentes ducts which link to the mesonephric duct to become ductus deferens.

Question 19

How do you make ovaries by PGCs?

Answer 19

Lack of Y chromosome results in sex cord dissociation into irregular cell clusters and degeneration of medullary cords. Cortical cords then develop from epithelium and penetrate underlying mesenchyme. This cord splits into cell clusters surrounding PGCs and the PGC become oogonia and surround cells to become follicular cells.

Question 20

So what is the major difference in differentiation between ovaries and testes?

Answer 20

the Y chromosome making sex cord persist

Question 21

Unspecialized gonads and 2 sets of reproductive ducts exist until (blank)

Answer 21

week 6

Question 22

What is the paramesonephric duct also called?

What is the mesonephric duct also called?

Answer 22

the mullerian duct

the wolffian duct

Question 23

What duct must degenerate to get rid of female parts so that you will have a male?

Answer 23

mullerian ducts

Question 24

How does the Y chromosome degenerate the mullerian ducts so that the baby will be male?

Answer 24

The sertoli cells secrete anti-mullerian hormones

Question 25

Once you have testis you will make interstitial cells which will make (blank) and thus make all the internal and external genitalia of males.

Answer 25

testosterone

Question 26

``` What makes these: Urethra Prostate Penis Scrotum ```

Answer 26

DHT

Question 27

``` What makes these: epididymis vas deferens seminal vesicles ejaculatory duct ```

Answer 27

Testosterone (only if they have SF1)

Question 28

(blank) gene activates a cascade of development events which create the testis and thus all the internal and external male genitalia

Answer 28

SRY

Question 29

Since females do not have SRY, they will create ovaries and thus their follicles will secrete (blank) which will convert the mullerian duct (paramesonephric duct) into the (blank)

Answer 29

estrogen | oviducts

Question 30

What three factors do you need to push the genital ridge into differentiation status?

Answer 30

SF1 WT1 LHX9

Question 31

What 2 factors do you need to turn the sex cord into the ovary? What 2 factors do you need to turn the sex cord into the testis?

Answer 31

DAX1, WNT4 | SRY,SOX9

Question 32

What do leydig cells need to make testosterone? and what will testosterone do?

Answer 32

SF1 | convert wolffian duct into male genitalia

Question 33

What does DHT do to the genital tubercle, urogenital sinus?

Answer 33

converts it into the penis, prostate

Question 34

The upper portion of mesonephric duct starts to branch and form (blank)

Answer 34

efferent duct

Question 35

The lower portion of the mesonephric duct starts to elongate and branch to make the (blank)

Answer 35

epididymis

Question 36

The lowest portion of the mesonephric duct elongates and forms (blank) and (blank)

Answer 36

vas deferens and seminal vesicles

Question 37

Efferent ducts, epididymis, vas deferens, seminal vesicles are all derived from (blank) under the influence of testosterone.

Answer 37

mesonephric ducts

Question 38

In the male genitalia, the excretory tubules remain while (blank) regress and change.

Answer 38

mesonephros

Question 39

In the male, epigenital tubules in contact with rete testis becomes (blank)

Answer 39

efferent tubules

Question 40

In the male, the caudal portion to the testes becomes the (blank)

Answer 40

paradidymis

Question 41

What ducts exist in both sexes?

Answer 41

mesonephric (wolffian ducts) and paramesonephric (mullerian) ducts

Question 42

Explain what happens to the paramesonephric ducts in the female?

Answer 42

the come from the genital ridges and cranial end opens to abdominal cavity and the 2 caudal ends grows and fuses together to make the uterine canal and paramesonephric tubercle

Question 43

Female genital ducts develop from the (blank)

Answer 43

paramesonephric ducts

Question 44

In the female what happens to the mesonephric ducts?

Answer 44

mesonephric duct regresses and the remnants form epoophoron and paroophron.

Question 45

What is this: | a small caudal portion of the mesonephric duct remnants in the wall of the uterus or vagina

Answer 45

Gartner's Cyst

Question 46

What are the three portions of the paramesonephric ducts?

Answer 46

upper-> uterine tube Lower-> uterine canal lowest-> fused part becomes corpus and cervi of the uterus

Question 47

The (blank) of the uterus divides the pelvic cavity into the uterorectal and uterovesical pouches.

Answer 47

broad ligament

Question 48

Where does the myometrium come from?

Answer 48

mesenchyme

Question 49

The vagina has dual origin, what are they?

Answer 49

upper portion from the uterine canal (from paramesonephric duct) lower portion from urogenital sinus

Question 50

(blank) is the epithelial lining of the sinus and a thin layer of vaginal cells. It is frequently absent (even in virgins) although remnants are commonly present as hymenal caruncula tags.

Answer 50

hymen

Question 51

How does the uterus and vagina form?

Answer 51

from the uterine canal and sinovaginal bulbs. paramesonephric ducts extend and make cervix and top 1/3 of vagina. Sinovaginal bulb extends and makes bottom 2/3 of vagina

Question 52

What are the three uterine defects?

Answer 52

uterus didelphys: double uterus uterus arcuatus: slightly indented in the middle Uterus bicornis: two uterine horns entering a common vagina

Question 53

What is atresia of the cervix? | What is atresia of the vagina?

Answer 53

unnatural narrowing of the cervix | unnatural narrowing of the vagina

Question 54

When the lower portion of the mesonephric ducts fuses you will get lumen formation which can lead to (blank).

Answer 54

vulnerabilities and possible defects

Question 55

In week 3 of development what happens with external genitalia development?

Answer 55

mesenchymal cells from primitive streak migrates around the cloacal membrane.

Question 56

What do the cloacal membranes turn into?

Answer 56

cloacal folds

Question 57

The cranial portion of the cloacal folds turn into what?

Answer 57

genital tubercle

Question 58

What does the anterior portion of the cloacal folds turn into?

Answer 58

urethral folds

Question 59

What does the posterior portion of the cloacal folds turn into?

Answer 59

anal folds

Question 60

Genital swellings in males turn into (blank). | in females?

Answer 60

scrotal swelling | labia majora

Question 61

What does the genital tubercle in male turn into? | in females?

Answer 61

penis | clitoris

Question 62

What do the urethral folds in male turn into? in females?

Answer 62

fuse=urethra | no fusion = labia minora

Question 63

What do the genital swellings in males turn into? in females?

Answer 63

fuse=scrotum | no fusion= labia majora

Question 64

Development of male external genitalia depends on (blank) produced by the fetal testis (leydig cells)

Answer 64

androgen

Question 65

In the male there is rapid elongation of the (blank) making a phallus/penis

Answer 65

genital tubercle

Question 66

(blank) pulls the urethral fold forward to make the urethral groove

Answer 66

phallus

Question 67

What is the male urethral groove lined with?

Answer 67

epithelium from endoderm and makes urethral plate

Question 68

In the male, At the end of the 3rd month, 2 urethral folds close over the urethral plate to make the (blank)

Answer 68

penile urethra

Question 69

What does the solid epithelial cord of the male turn into?

Answer 69

turns into the lumen which turns into the urethral outlet of the glans penis

Question 70

(blank) stimulates the development of the female external genitalia.

Answer 70

estrogen

Question 71

In the female, the genital tubercle slightly elongates at becomes the (blank)

Answer 71

clitoris

Question 72

In the female do the urethral folds fuse?

Answer 72

no they do not and form the labia minora

Question 73

What does the genital swelling of the female turn into?

Answer 73

the labia majora

Question 74

Can you tell the sex of a baby between the 3rd and 4th month of gestation by looking at genital tubercle? WhY?

Answer 74

no | because the genital tubercle in females in larger in those months than the male

Question 75

How can you tell you have a boy in the womb?

Answer 75

look for fusion of urethral folds, if fusion then a male

Question 76

What is incomplete fusion of urethral folds with abnormal openings in the urethra along the inferior aspect of the penis?

Answer 76

hypospadias

Question 77

Where are you most likely to get hypospadias and what is the incidence rate?

Answer 77

near the glans>shaft>base | 3/1000 (rates been increasing over past years)

Question 78

What might be the cause of hypospadias?

Answer 78

environmental estrogen

Question 79

(blank) is a malformation in which the urethra opens on the dorsum of the penis.

Answer 79

epispadias

Question 80

(blank) occurs as an isolate defect, but frequently associated with exstrophy of the bladder.

Answer 80

epispadias

Question 81

A lack of mesodermal migration into the region between the umbilicus and genital tubercle, followed by rupture of the thin layer of ectoderm results in (blank)

Answer 81

epispadias

Question 82

What is a micropenis?

Answer 82

2.5 standard deviations below average size for age group

Question 83

What does this cause: | insufficient androgen stimulation caused by hypogonadonism or hypothalamic or pituitary dysfunction

Answer 83

micropenis

Question 84

What happens if your genital tubercle splits?

Answer 84

bifid penis/double penis

Question 85

Where in the SRY cascade might there be vulnerability for mutant genes?

Answer 85

turning cholesterol to testosterone testosterone to DHT DHT receptors

Question 86

What causes pseudohermaphroditism?

Answer 86

congential adrenal hyperplasia

Question 87

Are pseudohermaphrodites male or female?

Answer 87

female, 46 XX with ovaries and uterus

Question 88

Why would excessive production of androgens cause pseudohermaphroditism?

Answer 88

it masculinizes external genitalia-> enlarges clitoris to male genitalia and partial fusion of the labia majora resembling scrotum

Question 89

What is testicular feminization (androgen insensitivity syndrome?

Answer 89

it is a disease where a male looks like a female 46 XY Testes present (cryptorchidism I.e hidden), all other genitalia is missing

Question 90

What causes androgen insensitivity syndrome?

Answer 90

A male is born with an XY chromosome, the Y chromosome makes the SRY chromosome making testes. So this individual will have testes however remember all other steps of creating male genitalia is dependent on testosterone. SO what happens is this individual has messed up androgen receptors so they will not respond to testosterone so they will not have any male genitalia and not any female internal genitalia because the testes produce the anti murelian ducts which destroy the ability to develop female internal genitalia. But you will still make estrogen so you will have female external genitalia (cuz this is influenced by estrogen) and look like a female but have testis.

Question 91

is androgen insensitivity syndrome common?

Answer 91

it is x-linked recessive, 1/20,000 live births

Question 92

The not descended testes of androgen insensitivity syndrome patients will result in a 1/3 chance to develop malignancy. T or F

Answer 92

T

Question 93

Describe the descent of the testes

Answer 93

develop in abdomen descend to scrotum through internal ring (inguinal canal) descends through external ring covered in tunica vaginalis gubernaculum attaches to caudal pole and to scrotum to assist descent

Question 94

What is a fibrous cord connecting 2 structures, it is a mesenchymalcolumn of tissue that connects the fetal testis to the developing scrotum and plays a role in testicular descent.

Answer 94

gubernaculum

Question 95

What is cryptorchidism?

Answer 95

one or both testes do not descend

Question 96

What is this: | vaginal process fails to close and intestines pass through the rings to scrotum

Answer 96

inguinal hernia (indirect)

Question 97

What is a hydrocele?

Answer 97

cysts secreting fluid

Question 98

If someone has cryptorchidism, how do you get the testes to descend?

Answer 98

use hCG. Since they are stuck you need to do this because the testes in the cavity will be unable to undergo spermatogenesis they will have a risk of cancer