8-D Development of the Reproductive System

Question 1

What is the embryonic origin of the urethra and vestibule?

Answer 1

cloaca

Question 2

What is the embryonic origin of the external genitalia?

Answer 2

genital swellings

Question 3

What is the embryonic origin of the gonad and duct system?

Answer 3

urogenital ridges

Question 4

The intermediate mesoderm aka_______ _____ gives rise to the gonad and duct system as well as the kidney and the duct system.

Answer 4

urogenital ridge

Question 5

Two ducts travel the length of the urogenital ridges, name them.

Answer 5

mesonephric duct (vas deferens and the seminal vesicles) and the paramesonephric duct (uterus and part of the vagina), these ducts are accompanied by the primitive gonad (testes or ovaries)

Question 6

The mesonephric duct empties into the ___ ____ of component of the cloaca, the paramesonephric duct ends blindly in the tissue between the ______ and ____ _____

Answer 6

urinary bladder; bladder and the anorectal canal

Question 7

The cranial end of the paramesonephric duct opens into the _______ cavity

Answer 7

peritoneal

Question 8

The partitioning of the cloaca creates what two structures?

Answer 8

the rectum/anus and the bladder/urethra

Question 9

What is the finger-like projection of the bladder into the umbilical cord?

Answer 9

allantois

Question 10

Name the 3 genital swellings

Answer 10

genital tubercle (penis or clitoris), labioscrotal folds (labia major, scrotum) and the urogenital folds (labia minora and ventral penis)

Question 11

Name the derivatives of the genital tubercle, urogenital/urethral folds and labioscrotal folds

Answer 11

penis/clitoris, ventral penis/labia minor and scrotum.labia major

Question 12

Describe the indifferent stage of gonadal development.

Answer 12

mesonephric and para mesonephric duct are in place, a segment of each urogenital ridge forms a primitive gonad, primary sex cords form by the ingrowth of coelomic epithelium and germ cells migrate from the gonad from the yolk sac

Question 13

The determination of gonadal sex is determined by ______ while the determination of the genital sex is governed by _______ factors

Answer 13

genes, hormonal factors

Question 14

What happens in determination of male gonadal sex?

Answer 14

SRY region on the Y chromosome cause the primitive sex cords to form the seminiferous tubules containing sertoli cells that help in germ cell production and the leydig cells the produce testosterone

Question 15

What happens during the determination of female gonadal sex?

Answer 15

in the absence of the Y chromosome, primitive sex cords break down and cells become follicular cells that associate with the germ cells

Question 16

The male reproductive duct system develops largely from _________ ducts.

Answer 16

mesonephric (the paramesonephric ducts largely regress/disappear)

Question 17

Differentiation of the vas deferens and epididymis form the mesonephric duct is mediated by____ while differentiation of prostate, seminal vesicles and external genitalia is mediated by ________ . (regression of the paramesonephric ducts is mediated by ____ ___ ___

Answer 17

testosterone, dihydrotestosterone, Mullerian Inhibiting Factor

Question 18

Testicular descent along the gubernaculum and final positioning of the testis in the scrotum is largely under the influence of_______

Answer 18

testosterone

Question 19

The female reproductive duct system develops largely from the ______ ducts

Answer 19

paramesonephric ducts

Question 20

How does the uterus form form the paramesonephric ducts?

Answer 20

paramesonephric ducts fuse across the midline to form the uterus and the uterine tubes and part of the vagina

Question 21

Name the two vestiges of the gubernaculum in the female.

Answer 21

ovarian ligament and round ligament of the uterus

Question 22

What tissue provides for the completion of the urtero vaginal canal?

Answer 22

sinuvaginal bulbs (20% of lower vagina) made of endoderm that grow to meet the fused paramesonephric ducts and cavitate to form the lower vagina

Question 23

What is the vestibule?

Answer 23

the space between the labia minora into which the vagina and urethra open

Question 24

Female external genital development involves ______ growth while development of the male external genital involves growth and extensive fusion of the the _____ and ______ folds across the midline

Answer 24

primary; urethral and labioscrotal folds

Question 25

Endoderm growing along then ventral surface of the forming penis becomes what?

Answer 25

penile urethra

Question 26

The component of the uretrha int eh glans forms by an ingrowth of the _____ from the tip of the glans.

Answer 26

ectoderm

Question 27

What is the name of the portion that must fuse along the ventral side of the penis?

Answer 27

penile and scrotal raphe

Question 28

What is hypspadias?

Answer 28

failure of the fusion of the urogenital folds

Question 29

What are variants that can occur if you the paramesonephric ducts don’t fuse properly?

Answer 29

bicornate and unicornuate uterus

Question 30

During the growth of the genital tubercle an outgrowth of endoderm from the first part of the urethra growing along the ventral surface (urethral plate/urethral groove) develops into the penile ____-

Answer 30

urethra

Question 31

What is considered the committed step in gonadal differentiation?

Answer 31

differentiation of primitive sex cords