Embryology

Question 1

Mesonephric duct

Answer 1

will form the wolffian duct

forms from intermediate mesoderm
drains into cloaca

will form epididymis, ductus deferens, ejaculatory duct; seminal vesicle

Question 2

paramesonphric duct

Answer 2

forms from intermediate mesoderm
drains into cloaca

forms the mullerian duct

will regress in males except for the appendix of the testes and prostatic utricle

Question 3

Indifferent gonad

Answer 3

weeks 6

has outer cortex and inner medulla with primitive sex cords

Question 4

testicular descent

Answer 4

1. About 97% of newborns are born with descended testes; of those that remain undescended, most will descend within about 3 days after birth.
2. Controlled by testosterone; but exact mechanism remains unknown.

pulled by the gubernaculum with the processus vaginalis

Question 5

cloacal-urethral folds

Answer 5

mesenchymal swelling around cloacal membrane

shaft, root of penis and penile urethra

a. Elongates along with the genital tubercle.
b. Urethra groove is an open grove on ventral penis.
c. Later, the two folds fuse to form the penile urethra.
d. The remaining portion of the urethra (in the glans penis) is formed by ectodermal cells that grow inward.

later divide into urethral and anal folds

Question 6

genital swellings

Answer 6

form on each side of cloacal membranes
(lateral)

will form the scrotum

Question 7

genital tubercle

Answer 7

under the influence of DHT and T

will form into the glans penis and the CS and CC

Question 8

hypospadia

Answer 8

penile urethra opens in abnormal position

1. Caused by incomplete fusion of the urethral groove on ventral surface of penis.
   T dependent

Question 9

epispadias

Answer 9

often with extrophy of bladder
T independent

urethral opening on top of penis

due to urethral plate developing more dorsally than normal

Question 10

hydrocele

Answer 10

fluid filled space around the testes
tunica vaginalis are serous membranes, which become hyperactive and exs serous fluid fills the testes (usually can just be absorbed in the first few mo. of life)

Question 11

Crytptochidism

Answer 11

testosterone dependent undescended testes

teste can be found anywhere (often in the abdomen, inguinal canal or spermatic cord)

this teste will be infertile due to temperature problems

**big risk factor for testicular cancer

Question 12

Formation of female genitalia

Answer 12

**E2 independent

just needs the absence of MIH (AMH)

the cortex forms the ovary and the medulla regresses

Question 13

female genital ducts

Answer 13

mesonephric ducts (wolffian) regress- MOSTLY, if they do not, they can form Gardner's cysts 
Paramesonephric ducts internal genitalia

Question 14

cranial portion of paramesonephric ducts

Answer 14

form fallopian tubes,

unfused

Question 15

caudal end of paramesonepthric ducts

Answer 15

fused, forms uterus, cervix and superior vagina

Question 16

sinovaginal bulb

Answer 16

from cloaca

induced by paramesonephric ducts, inferior portion of the vagina

vagina

Question 17

genital swellings female

Answer 17

labia majora

Question 18

urethra folds

Answer 18

labia minor
erectile tissue (bulbs of vestibule and crus of clitoris)
urethral groove remains unfused and will form the vestibule

Question 19

genital tubercle

Answer 19

elongates to form the clitoris

Question 20

uterus arcuatus

Answer 20

very slight lack of fusion of PM ducts

Question 21

uterus bicornis

Answer 21

partial lack of fusion of PM ducts

2 uterine horns

Question 22

uterus didelphys

Answer 22

complete lack of fusion of PM ducts and formation of two sinovaginal bulbs

**everything is duplicated: 2 uterine horns, cervixes, vaginas

Question 23

uterus bicornis unicollis

Answer 23

only 1 uterine horn forms up with the vagina and 1 rudimentary horn

Question 24

uterus unicornis

Answer 24

on PM ducts fails to form

Question 25

Klinefelter syndrome

Answer 25

47 XXY male

nondisjunciton 
testes form (due to SRY) but are infertile due to low T levels and high E 
more female secondary sex character 
impared sexual maturation at puberty 
gynecomastia

Question 26

Turner syndrome

Answer 26

1. 45, XO
2. Cause: Nondisjunction during meiosis
3. Gonadal dysgenesis(No ovaries or testes); streak gonads (Non functional genital ridge, bc you need two functional X’s)

the rest of internal and external gonads develop normal female

4. Lack of secondary sex trait development at puberty
5. Short-stature, broad chest, short neck; lymphedema of hands and feet

Question 27

Swyer syndrome

Answer 27

1. 46, XY
2. Cause: Point mutation of SRY gene resulting in defective TDF protein. (
3. Gonadal dysgenesis; streak gonads develop. These gonads can become cancerous; often removed before puberty.
4. Female external and internal genitalia (except for ovaries)
5. Amenorrhea
6. Lack of secondary sex trait development at puberty

essentially the same as Turner’s, due to the fact that you need 2 X to form ovaries)

Question 28

true Hermaphroditism

Answer 28

1. Presence of male and female gonadal tissue (within same or opposite gonad).
2. Ovotestes – ovarian and testis tissue found in same gonad.
3. Most have the 46, XX genotype.
4. Cause is most likely a translocation of portion of Y (containing SRY gene) onto X chromosome during meiosis.
5. Ambiguous external genitalia.

Question 29

Female pseudohermaphroditism

Answer 29

1. 46, XX
2. Cause: congenital adrenal hyperplasia (excessive production of androgens by adrenal glands).
3. Ovaries
4. Internal reproductive organs usually female
5. Masculinization of external genitalia, long clitoris, with a separate urethra

Question 30

Male pseudohermaphroditism

Answer 30

1. 46, XY
2. Testes form (due to normal functioning Y chromosome).
3. Insufficient androgen production and AMH (hypogonadism)
4. External and internal genitalia normally female

genetically male, but grow up female, need to treat with E2 at puberty

Question 31

androgen insenstivity

Answer 31

1. 46, XY
2. Testes (due to normal functioning Y chromosome)
3. AMH and testosterone production is normal
4. Lack of androgen receptors (tissues are not responsive to testosterone)
5. Mesonephric ducts degenerate (due to insensitivity to testosterone)
6. Paramesonephric ducts degenerate (due to presence of AMH)
7. Female external genitalia; including secondary sex traits
8. Vagina is short and blind-ending

**testes that do not descend, no other internal gonads