~5 - Development Of Genital System

Front 1

what are the 3 portions of development of the genital system?

Back 1

Gonads - testes and ovaries
Genital ducts
External genitalia

Front 2

what 2 stages are the 3 portions of development of the genital system divided into?

Back 2

undifferentiated &
differenciated

Front 3

when is the undifferenciated stage of development?

Back 3

first 6 weeks

Front 4

what is the 2nd week of development characterized by?

Back 4

the bilaminar disc (epiblast and hypoblast)

Front 5

what is week 3 of development characterized by?

Back 5

trilaminal disc: ectoderm, mesoderm, and endoderm

Front 6

the urogenital system develops from the intermediate ____________, which is carried ventrally during folding of the embryo and loses connection with the somites

Back 6

mesoderm

Front 7

the ___________ ridge is a longitudinal elevation of mesoderm that forms on each side of the aorta

Back 7

urogenital

Front 8

the urogenital ridge has 2 parts, name them and what they become

Back 8

nephrogenic cord- urinary system
genital ridge- genital system

Front 9

the gonads first appear as a pair of ___________ ridges

Back 9

genital

Front 10

the indifferent stage is defined by 3 groups of cells, name them

Back 10

primordial germ cells
mesenchyme
mesodermal epithelium

Front 11

the _______________________ originate in endoderm of yolk sac near allantois, migrate into intermediate mesoderm, and if fail to develop --> no gonadal development

Back 11

primordial germ cells

Front 12

___________ of the genital ridge is dervided from intermediate mesoderm

Back 12

mesenchyme

Front 13

__________________ (_____________) of the genital ridge proliferates and forms the primary sex cords that incorporate primordial germ cells and penetrate the mesenchyme of the genital ridge

Back 13

mesodermal epithelium (mesothelium)

Front 14

at the end of the 6th week (end of indifferent stage), the gonad consists of what 2 things, (inner and outer)

Back 14

an outer cortex and inner medulla

Front 15

on what gene is the determining factor of XY differentiation located, and what does it encode?

Back 15

SRY gene on the short arm of the y chromosome encodes the testis determining factor (TDF)

Front 16

in male differencitation, what do the undifferentiated medulla and cortex become?

Back 16

medulla - proliferates to form testes
cortex - regresses

Front 17

the medualla and __________ proliferate to form testes

Back 17

sex cords

Front 18

near the hilum of the testes, the sex cords form a network of tubules termed the _____________

Back 18

rete testis

Front 19

in the testes, primitive seminferous tubules develop from the sex cords and contain 2 types of cells, what are they?

Back 19

Sertoli cells and primordial germ cells

Front 20

______ cells are from mesodermal epithelium and produce antimullerian hormone (AMH)

Back 20

Sertoli

Front 21

Anti mullerian hormone (AMH) produced by the _________ cells causes regression of what?

Back 21

sertoli

regression of paramesonephric duct

Front 22

what do the primaitive germ cells of the testes become at puberty?

Back 22

spermatogonia

Front 23

interstitial cells of _______ at located where in reference to the sex cords?

they form from the mesenchymal ridge and by the 8th week produce what?

Back 23

Leydig interstitial cells are located BETWEEN the sex cords and produce testosterone by weel 8

Front 24

the ______________ is the fibrous covering of the testes; it's a dense layer of fibrous ct that separates the sex cords from the mesodermal epithelium

Back 24

tunica albuginea

Front 25

T/F: the primordial germ cells of differenciating females has an SRY gene

Back 25

FALSE:
the SRY gene is only found on the short arm of the Y chromosome (contains the TDF)

Front 26

As the gonads differentiates into ovaries, what happens to the medulla and cortex?

Back 26

the medulla regresses and the cortex proliferates to form the ovaries

Front 27

T/F:
the primary sex cords in medulla degenerate in absence of Y chromosome

Back 27

TRUE

Front 28

with female differentiation, the primary sex cords degenerate, but secondary sex cords form from ___________ called what?

Back 28

primordial germ cells

cortical cords

Front 29

in the female, what do the primordial germ cells differentiate into?q

Back 29

oogonia

Front 30

during the ________ month of development, the oogonia undergo mitosis

Back 30

3rd

Front 31

in the ____ month of development, the cortical cords dissociate into cell clusters containing oogonia and follicular cells

Back 31

4th

Front 32

what do the oogonia come from?

what do the follicular cells come from?

Back 32

oogonia- primordial germ cells

follicular cells- mesothelium

Front 33

__________ (____________) ducts are adjacent to mesenephros, attached to mesonepheric tubules, and extend from the mesonephros to the urogenital sinus; there is NO distal fusion

Back 33

mesonephric ducts (Wolffian)

Front 34

_____________ (___________) ducts lie more lateral; cranial ends open into the peritoneal cavity; the caudal ends pass more ventral, FUSE at the distal midline and terminate on the dorsal wall of urogenital sinus

Back 34

paramesonephric ducts (Mullerian)

Front 35

in males, the interstitial cells of Leydig produce ________ which stimulates the development of ________ ducts

Back 35

testosterone

mesonephric ducts

Front 36

iIn males, Sertoli cells produce ________________ hormone which suppresses the development of ___________ ducts

Back 36

anti-muellian hormone

paramesonephric ducts

Front 37

mesonephric tubules form the ________ ___________ of the testes

Back 37

efferent ductules

Front 38

what 4 things do the mesonephric ducts form in males?

Back 38

epididymus
ductus deferens
ejaculatory duct
seminal vesicle

Front 39

remnants of the paramesonephric ducts in males form the _____________

Back 39

appendix testis

Front 40

in females, the ___________ tubes and ducts degenerate

Back 40

mesonephric

Front 41

epoophoron and paroophoron are remnants of what?

Back 41

mesonephric tubules

Front 42

duct of epoophoron is a remnant of what?

Back 42

mesonephric ducts

Front 43

____________ ducts become what female genital tract

Back 43

paramesonephric

Front 44

the cranial portions of the paramesonephric ducts in females *do/do not* fuse. what do they form?

Back 44

DO NOT --> uterine tubes

Front 45

the caudal portion of the paramesonephric ducts in females *do/do not* fuse. what do they form?

Back 45

DO! --> uterus and cranial (superior) vagina

Front 46

by the ____ month, the solid vaginal plate of endoderm from the urogenital sinus canalizes

Back 46

5th

Front 47

the indifferent stage of external genitalia development is from ___ - ___ weeks

Back 47

4 - 7 weeks

Front 48

mesenchymal cells proliferate around teh cloacal membrane to form a pair of slight elevations termed _______ folds

Back 48

cloacal

Front 49

the ______ tubercle cranial to the cloacal membrane

Back 49

genital

Front 50

the ________ fold and ___________ swellings are lateral to the cloacal membran

Back 50

urogenital (urethral) fold and labioscrotal (genital) swellings

Front 51

when the genital tubercule elongates, it forms the ________

Back 51

phallus

Front 52

the cloacal membrane eventually becomes separates into 2 parts by the __________ _______. name the two parts and their orientation

Back 52

urorectal septum

urogenital membrane -anteriorly
rectal membrane - posteriorly

Front 53

external genitalia of male develops under the influence of ________ from the testes

Back 53

androgens

Front 54

the urethral groove is formed by the lateral walls of the _____A______ as they are pulled forward by the elongation of the ____B_____ after the ______C_____ membrane ruptures

Back 54

A: urogenital folds
B: phallus
C: urogenital membrane

Front 55

males:
the urethral plate of the urethral groove is formed by the epithelial lining that is from what dermal layer?

Back 55

endoderm

Front 56

males:
the __________ elongates to form the glans and dorsal wall of body of penis

while the ____________ fuse and form the ventral body wall of the penis

Back 56

dorsal: phallus

ventral: urogenital folds

Front 57

males:
the ____A______ of the urethral groove forms the epithelium of the spongy urethra (except in area of the glans)

an ingrowth of ____B______ cells forms the urethra in the area of the glans

Back 57

A: ENDODERM

B: ECTODERM

Front 58

the _________________ fuse to form the scrotum

Back 58

labioscrotal swellings

Front 59

formation of external genitalia occurs during weeks ___ - ____

Back 59

8 - 12

Front 60

females:
__________ remains small (no elongation) and forms the clitoris

Back 60

phallus

Front 61

females:
phallus does not elongate because of absence of ___________

Back 61

androgens

Front 62

females:
__________ do not fuse with each other as they do in the male, and they form the labia minora

Back 62

urogenital folds

Front 63

females:
the ___________ do not fuse with each other as they do in the male, and they form the labia majora

Back 63

labioscrotal swellings

Front 64

females:
the space surrounded by the labia minora; formed by the break down of the urogenital membrane of the vagina

Back 64

vestibule

Front 65

where do the testes originate?

Back 65

in the posterior abdominal wall (external to the peritoneum)

Front 66

the ____________ is a ligament that attached to the caudal end of the testes and extends to the labioscrotal swellings

Back 66

gubernaculum

Front 67

by the ____ month, the testes have descending to the deep inguinal rings

Back 67

7th month

Front 68

by the 7th month, the periotoneum has evaginated inferiorly into the anterior abdominal wall forming the ____________________ that carries the muscular and fascial extensions of anterior abdominal wall

Back 68

processus vaginalis

Front 69

in the ___ and ___ months, the testes descend into the scrotum following the course of the ___________-

Back 69

8th and 9th

gubernaculum

Front 70

T/F:
at birth the testes should be in their final position

Back 70

true

Front 71

the testes are **posterior/anterior** to the processus vaginalis

Back 71

posterior

Front 72

once the testes have descended, the process vaginalis degenerates except where it is adjacent to ___________, and it forms the ___________ here

Back 72

the testes

tunica vaginalis

Front 73

the testes and tunica vaginalis are covered by extensions of abdominal muscles:
1) the internal spermatic fascia is an extension of the ___________
2) the cremasteric fascia and muscle are extensions of the ________
3) the external spermatic fascia is an extension of the __________

Back 73

1) transversalis fascia
2) internal abdominal oblique
3) external abdominal oblique

Front 74

as the testes descend, which stage (inital or final descent) of growth occurs via differential growth, and which as a result of androgens?

Back 74

initial - differential growth
final - androgens

Front 75

by the ____ month, the ovaries have descended just below the rim of the pelvis

Back 75

3rd

Front 76

in the female, the gubernaculum becomes the ________ ligament cranially and the ________ ligament of the uterus caudally

Back 76

ovarian lig cranially

round lig. of uterus caudally

Front 77

CC: Devel of Genital Sys

individuals with characteristic of both sexes

Back 77

hermaphrodite

Front 78

CC: Devel of Genital Sys

individual possesses both ovarian and testicular tissue (internally); external genitalia apprears ambiguous

Back 78

True hermaphrodite

Front 79

CC: Devel of Genital Sys

gonad of one sex, external genitalia od opposite sex; 2 different kinds when possesses ovaries vs. testes

Back 79

psuedohermaphrodite

w/ ovaries: female pseudohermaphrodite

w/ testes: male pseudohermaphrodite

Front 80

CC: Devel of Genital Sys

most common cause of female pseudohermaphroditism; individual has XX chromosomes and ovaries but there is masculization of female external genitalia; elarged clitoris, partial fusion of labia majora;

Back 80

adrengenital syndrome (aka congenital adrenal hyperplasia)

Front 81

CC: Devel of Genital Sys

embryological explanation for Adrenogenital syndrome:
-(dec/inc) systhesis of cortisol in adrenal glands
-(dec/inc) secretion of adrenocorticotropic hormone (ACTH)
-(dec/inc) secretion of androgens in adrenal cortex

Back 81

- decreased
- increased
- increased

Front 82

CC: Devel of Genital Sys

has XY chromosomes and testes, appears and raised as normal female, but vagina ends blindly; emb: testes secrete androgens but ext. genitalia are either insensitive or cells lack androgen receptors; do dx'd until puberty; amenorrhea, remove testes and con't rearing as female

Back 82

Androgen insensitivity syndrome (AIS) aka testicular feminization

Front 83

CC: Devel of Genital Sys

abnormal openings of urethra that occur on ventral side of the penis; emb- urogenital folds fail to fuse due to either inadequate androgen production or lack of receptor sites for androgens

Back 83

hypospadias

Front 84

CC: Devel of Genital Sys

testis (or testes not in scrotum at birth); emb- deficiency in androgen production; surgical placement in scrotum; increased chance of malignancy

Back 84

undescended testes (cryptorchidism)

Front 85

cryptochidism
___% of premature males
___% of full term males
___% of undescended testes descend by 1st b-day

Back 85

30% of premi's
3 % of full terms
80% descend by first b-day