Reproductive Embryology

Question 1

source of gonads (as far as tissue and location)

Answer 1

thickened area of mesoderm develops on the medial side of mesonephros creating a bulge in week 5 — the gonadal ridge

Question 2

indifferent gonads consist of

Answer 2

external cortex and internal medulla

Question 3

in XX embryo, cortex _____ and medulla ____

in XY embryo, cortex ______ and medulla _____

Answer 3

forms ovaries; regresses

regresses; forms testes

Question 4

gonads are indifferent until week ____

Answer 4

7

Question 5

originate in the wall of the umbilical vesicle and migrate to gonadal ridges

Answer 5

primordial germ cells

Question 6

primordial germ cells invest into the _____ and eventually form ____ or _____

Answer 6

gonadal cords

oocytes or sperms

Question 7

directs gonad differentiaion

Answer 7

SRY gene for testis-determining factor (TDF)

Question 8

TDF induces ________ to condense and extend into the medulla of the indifferent gonads, to form _______

Answer 8

gonadal cords

rete testis

Question 9

thick, fibrous capsule that separates the gonadal cords from the surface

Answer 9

tunica albuginea

Question 10

form interstitial (Leydig) cells that secrete androgen testosterone at week 8

Answer 10

Seminiferous tubules

Question 11

where are sustenacular (Sertoli) cells and what do they do?

Answer 11

Seminiferous tubules

secrete mullerian inhibiting substance (MIS) aka antimullerian hormone

Question 12

what does mullerian inhibiting substance do?

Answer 12

suppresses the formation of female structures

Question 13

forms efferent ductules which eventually connect to ductus epididymis

Answer 13

rete testis

Question 14

in ovary development, gonadal cords extend into medulla of ovary and form

Answer 14

rete ovarii

Question 15

in ovary development, cortical cords extend from surface epithelium of developing ovary in to the underlying mesenchyme.

__________ move in.

cords create clusters called ________ which consists of an _______ surrounded by a singular layer of _________ from surface epithelium

active mitosis produces _________ before birth (many degenerate)

Answer 15

primordial germ cells

primordial follicles; oogonium; follicular cells

2 million primary oocytes

Question 16

2 pairs of ducts in both male and female embryos

________ develop i male

________ develop in female

Answer 16

Mesonephric (Wolffian) ducts

Paramesonephric (Mullerian) ducts

Question 17

in development of male genital ducts, fetal testes produce testosterone and MIS.

What do they do?

Answer 17

MIS - inhibits paramesonephric (Mullerian) duct formation

testosterone - stimulate mesonephric (Wolffian) duct formation

Question 18

the mesonephric ducts are transformed into _____ and _______ and smooth muscle invests and forms

Answer 18

efferent ductules and duct of epididymis

ductus deferens

Question 19

Three male glands

Answer 19

Seminal vesicle

prostrate gland

bulbourethral gland

Question 20

lateral outgrowth from caudal end of each mesonephric duct forms

Answer 20

seminal vesicle

Question 21

endodermal outgrowths arise from the prostatic part of the urethra to form

Answer 21

prostrate gland

Question 22

develops from paired outgrowths from the spongy part of the urethra

Answer 22

bulbourethral gland

Question 23

paramesonephric ducts develop ______ from unfused cranial parts

Answer 23

uterine tubes

Question 24

caudal, fused portion of paramesonephric duct forms ______ which forms _____ and ______

Answer 24

uterovaginal primordium

uterus

superior portion of vagina

Question 25

in development of vagina, epithelium from ENDODERM of ________ contacts _________

Answer 25

urogenital sinus uterovaginal primordium

Question 26

forms sinovaginal bulbs that fuse to form vaginal plate

Answer 26

sinus tubercle

Question 27

in vaginal plate, central cells break down to form ______

Answer 27

lumen of vagina

Question 28

persistent membrane formed by invagination of posterior wall of urogenital sinus

Answer 28

hymen

Question 29

external genitalia and undifferentiated up to week ___ and characteristics appear during week ____. Fully differentiated by week ____

Answer 29

7 9 12

Question 30

The genital tubercle forms in week 4 from mesenchyme, then what?

Answer 30

labioscrotal swellings and urogenital folds develop on either side. tubercle elongates to form primordial phallus

Question 31

male external genitalia: primordial phallus enlarges and elongates to form

Answer 31

penis

Question 32

male external genitalia: urogenital folds form lateral walls of ______ on ventral surface of penis folds fuse to form _____

Answer 32

urethral groove spongy urethra

Question 33

male external genitalia: at the ________ and ectodermal ingrowth extends inward to meet spongy urethra and canalizes

Answer 33

glans penis

Question 34

male external genitalia: circular ectodermal ingrowth occurs in the periphery of the glans penis and forms the

Answer 34

prepuce (foreskin)

Question 35

male external genitalia: mesenchyme in the phallus forms ________ and _______ erectile tissue

Answer 35

corpora cavernosa corpus spongiosum

Question 36

male external genitalia: labioscrotal swellings grow toward each other and fuse to form scrotum - this forms the

Answer 36

scrotal raphe line

Question 37

female external genitalia: growth of phallus gradually decreases to form

Answer 37

clitorus

Question 38

urogenital folds do not fuse anteriorly, but form

Answer 38

labia minora

Question 39

labioscrotal folds do not fuse, but form

Answer 39

labia majora

Question 40

testes descend retroperineally from _____ to ______

Answer 40

posterior abdominal wall to deep inguinal rings

Question 41

descent of testes is induced by _____ by week _____ and takes ______ (length of time)

Answer 41

androgens by week 26 2 to 3 days

Question 42

the descending testes carry _____ and ______ with it while getting covered with

Answer 42

ductus deferens vessels layers of abdominal wall

Question 43

layers of abdominal wall: transversalis fascia becomes internal oblique muscle becomes external oblique aponeurosis becomes

Answer 43

internal spermatic fascia cremaster muscle and fascia external spermatic fascia

Question 44

attached to uterus near the attachment of uterine tube, for descent of ovaries

Answer 44

gubernaculum

Question 45

the gubernaculum does NOT pull ovaries down. The cranial part becomes ____ and the caudal part becomes _____

Answer 45

ovarian ligament round ligament

Question 46

undescended testes

Answer 46

cryptorchidism

Question 47

ambiguous genitalia (hermaphrodite no longer used)

Answer 47

intersex

Question 48

46, XX error in sex determination giving both testicular and ovarian tissue; phenotype male or female but genitalia always ambiguous

Answer 48

ovotesticular DSD - true gonadal intersex

Question 49

inadequate production of testosterone and AMH by fetal testes, testicular development ranges from rudimentary to normal

Answer 49

46 XY DSD

Question 50

exposure of fetus to excessive androgens in utero - masculinization of external genitalia but no ovarian abnormality

Answer 50

46 XX DSD

Question 51

"testicular feminization syndrome" failure of masculinization

Answer 51

androgen insensitivity syndrome (AIS)