5: Reproductive System Development

Question 1

Embryonic layer of the genital ridge

Answer 1

Intermediate mesoderm

Question 2

Where is the SRY gene

Answer 2

On sex-determining region of Y chromosome

Question 3

Three parts of the indifferent external genitalia’s phallic segment of the urogenital sinus

Answer 3

Urogenital plate, glans plate, genital tubercle

Question 4

Urogenital plate

Answer 4

Rupture of cloacal membrane opens phallic portion to exterior

Question 5

Glans plate

Answer 5

Remnants of cloacal plate at ventral end

Question 6

Genital tubercle

Answer 6

Ectoderm-covered mesodermal swelling at ventral and cranial end of phallic segment

Question 7

Other name for SRY gene

Answer 7

TDF: testes determining factor

Question 8

What do Sertoli cells produce at puberty and what it does

Answer 8

Androgen binding factor -> spermatogonia to spermatozoa

Question 9

What do adult leydig cells produce? What function?

Answer 9

Androgens -> initiation of spermatogenesis, masculinization of the brain, male sexual behavior

Question 10

5a reductase function

Answer 10

Testosterone -> dihydrotestosterone

Question 11

How does a double or bicornate uterus form?

Answer 11

L and R paramesonephric ducts dont properly fuse

Question 12

How does vaginal agenesis usually occur?

Answer 12

Failed sinovaginal bulb development

Question 13

Most common birth defect after cryptorchidism

Answer 13

Hypospadia

Question 14

Epispadia

Answer 14

Genital tubercle forms beneath phallus -> urethral opening on ventral penis

Question 15

Disorders of sex development (DSD)

Answer 15

Conditions in which development of chromosomal, gonadal, and sex is atypical; genotype sex is masked by phenotypic appearance resembling the opposite sex or having reproductive organs of opposite sex

Question 16

Approximate incidence of DSD

Answer 16

1 in 5,000

Question 17

Male DSD

Answer 17

Has testes but phenotype is female, 46 XY

Question 18

Four major causes for male DSDs

Answer 18

1. Mutation in AMH or AMH receptor
2. Inadequate testosterone synthesis
3. Androgen insensitivity syndrome
4. 5a-reductase deficiency

Question 19

Female DSD

Answer 19

Has ovaries, 46 XX

Question 20

Genetics of androgen insensitivity syndrome

Answer 20

X linked recessive, 1 in 20,000

Question 21

What occurs in fetus with androgen insensitivity

Answer 21

1. AMH produced -> no uterus, uterine tube, or part of vagina
2. Testes form in inguinal or labial region

Question 22

What happens in androgen insensitivity syndrome at puberty?

Answer 22

Testosterone metabolized into estradiol, initiating female secondary characteristics

Question 23

Increased risk in androgen insensitivity syndrome

Answer 23

Increased risk of tumor in gonads

Question 24

5a-reductase deficiency presentation

Answer 24

Normal testes and duct system, but underdeveloped male external genitalia (may even exhibit female phenotype depending on level of deficiency)

Question 25

Female DSDs process

Answer 25

Fetus produces excess androgens -> masculinization of female external genitalia

Question 26

Most common cause of female DSD

Answer 26

Congenital adrenal hyperplasia

Question 27

Congenital adrenal hyperplasia mutation

Answer 27

Genes involved in Adrenocortical steroid biosynthesis (ex: 21-hydrolase)

Question 28

When can female and male genitalia be recognized in a fetus?

Answer 28

Week 12