Development of the Genital System

Question 1

during what week does sexual differentiate begin

Answer 1

week 7

Question 2

at what week can male and female genitalia be recognized?

Answer 2

week 12

Question 3

at what week are phenotypic differentations complete

Answer 3

week 20

Question 4

primordial germ cells are specified in what early germ layer?

Answer 4

epiblast layer

Question 5

around week 5, the primordial germ cells migrate up the dorsal mesentery to enter what structure

Answer 5

the genital ridge

Question 6

somatic support cells in males and females

Answer 6

males: sertoli cells
female: follicle cells

Question 7

somatic support cells originate from what structure/cell type

Answer 7

proliferating body epithelium cells displaced by germ cells

Question 8

both mesonephric and paramesonephric ducts in the embryo develop from what layer

Answer 8

intermediate mesoderm

Question 9

the mesonephric duct is also known as the _____ duct

Answer 9

wolffian duct

part of early kidney development

Question 10

the paramesonephric duct is also known as the ____ duct

Answer 10

mullerian duct

Question 11

in males, the wolffian duct (derived from the _____ duct) remains to form what structures

Answer 11

mesonephric - epididymis, vas deferens, seminal vesicles, ejaculatory ducts

Question 12

in females, the mullerian ducts (derived from the _____ duct) remains to form what structures

Answer 12

paramesonephric - oviduct, uterus, upper vagina

Question 13

sexual dimorphism is dependent on what chromosome

Answer 13

Y chromosome but also dependent on autosomes as well

Question 14

what is the sex determining region of the y chromosome

Answer 14

the SRY gene

Question 15

the SRY gene determines what

Answer 15

gonad type

which determines duct and genitalia development

Question 16

in the absence of SRY, development of what phenotype occurs

Answer 16

female

Question 17

SRY gene is expressed in what cell type

Answer 17

the somatic support cells (pre-sertoli)

sertoli cells surround primordial germ cells to organize seminiferous tubules

Question 18

a subset of undifferentiated tubular cells are induced by the _____ cells to produce what hormone
what are these cells called

Answer 18

sertoli cells
testosterone
leydig cells

Question 19

what is the major transcription factor driven by SRY gene

Answer 19

sox9

Question 20

what is the primary target of sox9 gene

Answer 20

anti-mullerian hormone

results in regression of mullerian (paramesonephric) duct between weeks 8-10

Question 21

the \_\_\_\_ cells drive mesonephric ducts to form 
efferent ductules 
epididymus 
vas deferens 
seminal vesicles

Answer 21

leydig cells

Question 22

derivatives of the mesonephros

Answer 22

efferent ductueles
epididymus
vas deferens
seminal vesicles

Question 23

fetal leydig cells produce what two enzymes

Answer 23

testosterone (weeks 8012) driven by HCG from placenta
induces mesonephric duct to form ductus deferens, epididymus, seminal vesicles

5alpha reductase to turn testosterone into dihydrostestosterone which induces
genital tubercle to become penis
genital swellings to become scrotum
urethral epithelium to form prostate

Question 24

adult leydig cells produce what hormones to drive what differentiation

Answer 24

andorgens
initiation of spermatogenesis
masculinization of brain
male sexual behavior

Question 25

products of sertoli cells

Answer 25

AMH (regression of paramesonephric duct) | Androgen binding factor (spermatogonia --> spermatazoa)

Question 26

seminal vesicles are derived form what duct

Answer 26

mesonephric dcut | intermediate mesoderm of urogenital ridge

Question 27

prostate is formed by buds of _____ from the UG sinus in t he region of pelvic urethra during what week

Answer 27

buds of endoderm | week 10

Question 28

prostate and _____ are derived from endoderm

Answer 28

bulbourethral glands

Question 29

rupture of cloacal membrane opens phallic portion of urogenital sinus to exterior forming endodermally lined plate called the ______ plate

Answer 29

urogenital plate

Question 30

remnants of cloacal membrane at the ventral end of the urogenital plate and adjacent genital tubercle

Answer 30

glans plate

Question 31

swelling of mesoderm covered by ectoderm at the vetnral and cranial end of phallic portion of urogenital plate

Answer 31

genital tubercle

Question 32

_____ drives lengthening and growth of genital tubercle and fusion of labioscrotal swellings to form scrotum

Answer 32

Dihydrotestosterone

Question 33

in the presence of DHT, the labioscrotal swellings fuse to form what adult structure

Answer 33

scrotum

Question 34

second most common birth defect after cryptorchidism

Answer 34

hypospadias | urethral folds didnt fuse

Question 35

without the SRY gene, what transcription factor is able to suppress SOX9

Answer 35

Wnt-4

Question 36

along with wnt4, what transcription factor suppresses SOX9 constantly

Answer 36

FOXL2

Question 37

somatic cells not under the signal of Sox9 form what type of cells

Answer 37

follicle and primoridal germ cells (--> oogonia)

Question 38

without sertoli cells, no AMH is produced, therefore the ____ ducts develop and form

Answer 38

the paramesonephric ducts develop and fallopian tubes, uterus, and upper portion of vagina are formed

Question 39

without leydig cell, the signal to retain the ____ duct is lost

Answer 39

wollfian (mesonephric)

Question 40

fusion of the ______ _____ ducts form the uterus

Answer 40

fusion of the inferior paramesonephric ducts

Question 41

uterine tubes are the unfused portion of the ________ ducts

Answer 41

paramesonephric ducts

Question 42

the upper vagina is derived from ________ | the lower vagina is derived from ________

Answer 42

upper - mesoderm | lower - endoderm

Question 43

the superficial vagina begins as what structure

Answer 43

sinovaginal bulbs

Question 44

without the signal of DHT, the genital tubercle is not lengthened and the urogenital folds dont fuse resulting in what two structures

Answer 44

labia minora | labia majora

Question 45

formation of the broad ligament

Answer 45

midline fusion of the parameso0nephric ducts brings lower urogenital ridge within the pelvic cavity and its covered inn peritoneum upon completion of uterus and oviduct formation, the remaining tissue thins forming a double fold of peritoneum

Question 46

congenital conditiosn in which development of chromosomal, gonadal, and anatomic sex is atypical

Answer 46

disorders of sex development

Question 47

XY DSDs

Answer 47

XY 46 ahs testis but phenotype is female caused by inadequate testosterone synthesis 17 beta hydroxysteroid dehydrogenase 3 androgen insensitivity syndrome 5-alpha reductase deficiency mutations in AMH or AMH receptor

Question 48

characteristics of androgen insensitivity syndrome

Answer 48

commonly caused by loss of fucntional androgen receptors have testis but no spermatogenesis; testosterone levels may be high testosterone at puberty is metabolized to estradiol initiating female secondar ycharactersitics but patients exhibit amenorrhea no uterus or uterine tubes; vagina is short and ends blindly

Question 49

5 alpha reductase deficiency

Answer 49

46 XY genotype autosomal recessive normal testis and duct system underdeveloped male external genitalia depending on level of deficiency, can exhibit external female phenotype

Question 50

congenital adrenal hyperplasia

Answer 50

most common cause of female sexual ambiguity 46 XX have ovaries but produce androgens masculinization of the female external genitalia; may even exhibit fusion of labia giving appearance of scrotum

Question 51

ovotesticular disorders

Answer 51

true interseexuality have both testicular and ovarian tissue ambiguous external genitalia or predominatnly female; usually have a uterus caused by: translocation of piece of Y onto X, subset of cdells may have mutation in Y, oanomaly in sex determination and differentiation of primoridal germ cells