Repro Development

Question 1

the ____ _____ appear in the 5th week on the medial aspect of the _____ which give rise to ____/______

they are indistinguishable until week __

Answer 1

the gonadal ridges appear in the 5th week on the medial aspect of the mesonephros which give rise to testes/ovaries

they are indistinguishable until week 7

Question 2

the _____ forms the male gonads

the ____ forms the female gonads

Answer 2

the medulla forms the male gonads

the cortex forms the female gonads

Question 3

describe what the Y chromosome encodes for

Answer 3

• Testis determining factor (TDF) encoded by the SRY gene on the short arm of Y chromosome which turns on testis development

Question 4

what do the Sertoli cells produce?

Answer 4

Antimullerian hormone (AMH)

produced until puberty to suppress development of female ductal system

Question 5

describe the 2 phases of testicular descent

Answer 5

• transabdominal
  
  • “descent” of testis is a result of abdominal growth
• inguinal
  
  • controlled by testosterone, guided into scrotum by gubernaculum

Question 6

describe a congenital inguinal hernia

Answer 6

• if the connecting portion of the processes vaginalis does not obliterate, it leaves a patency in the inguinal canal where intestines may herniate through

Question 7

describe a hydrocele

Answer 7

• the processes vaginalis contains a small amount of fluid before it obliterates
• if the fluid does not get reabsorbed = hydrocele
• identified by transilumination

Question 8

describe cryptorchidism

Answer 8

• testes do not descend into the scrotum
• may be bi- or unilateral
• testes can be anywhere along the normal descent pathway
  
  • usually found in the inguinal canal
• higher risk of germ cell tumors

Question 9

describe ectopic testis

Answer 9

• after descending into the inguinal canal, it may become lodged in other areas
  
  • there is descent

Question 10

development of the _______ ______ lead to male genital ducts, which is stimulated by ______ from the _____ ______

Answer 10

development of the mesonephric ducts lead to male genital ducts, which is stimulated by testosterone from the Leydig cells

Question 11

development of the _______ ______ lead to female genital ducts, unless suppressed by ______ from _____ _____ of developing teses

Answer 11

development of the paramesonephric ducts lead to female genital ducts, unless suppressed by AMH from Sertoli cells of developing teses

Question 12

the _____ _____ thickens acquiring smooth muscle and becomes the ____ _____

Answer 12

the mesonephric duct thickens acquiring smooth muscle and becomes the ductus deferens

Question 13

outgrowth from the caudal end of the ______ _____ gives rise to the ____ _____

Answer 13

outgrowth from the caudal end of the mesonephric ducts gives rise to the seminal vesicles

Question 14

endodermal outgrowths from the _____ _____ differentiate into glandular tissue giving rise to ________

Answer 14

endodermal outgrowths from the prostatic urethra differentiate into glandular tissue giving rise to the prostate

Question 15

bulbourethral glands are paired outgrowths from the ____ _____

Answer 15

bulbourethral glands are paired outgrowths from the spongy urethra

Question 16

describe the uterovaginal primordium

Answer 16

gives rise to the superior portion of the vagina

Question 17

describe the sinovaginal bulbs

Answer 17

fuse to form a vaginal plate which breaks down to form the vaginal canal

Question 18

describe the formation of the hymen

Answer 18

formed by an invagination of the posterior wall of the urogenital sinus that separates the vaginal cavity from the urogenital sinus

Question 19

describe the formation of the greater vestibular glands

Answer 19

they form as an outgrowth of the urogenital sinus in the lower 1/3 of the labia majora

Question 20

describe how a double uterus forms

Answer 20

incomplete fusion of the paramesonephric ducts

Question 21

describe the formation of a bicornate uterus

Answer 21

2 uterus cavities separated by a septum: incomplete fusion is only superior

Question 22

describe the formation of a unicornate uterus

Answer 22

incomplete development of one of the paramesonephric ducts

Question 23

describe how vaginal agenesis can occur

Answer 23

failure of the sinovaginal bulbs to develop and form the vaginal plate

absence of the vagina is usually accompanied by absence of the uterus since the development of the uterus induces the formation of the sinovaginal bulbs

Question 24

describe vaginal atresia

Answer 24

incomplete canalization of the vaginal canal

Question 25

describe the Canal of Nuck

Answer 25

in females, the round ligament passes through the inguinal canal and also carries with it a portion of the peritoneum

if the processes vaginalis remains patent, it is called the Canal of Nuck and is subject to hernias and hydrocele

Question 26

describe the formation of the spongy (penile) urethra

Answer 26

the urethral folds fuse on the ventral surface of the penis to form the spongy (penile) urethra and the penile raphe (where surface ectoderm meets in the midline)

Question 27

describe the formation of the corpus cavernosum and spongiosum

Answer 27

the corpus cavernosum and spongiosum develop from the mesenchyme in the phallus

Question 28

describe the formation of the scrotum

Answer 28

the scrotum forms when the labioscrotal folds grow together and fuse

Question 29

describe hypospadias

Answer 29

failure of urethral folds to fuse results in abnormal orifices on the ventral surface of the penis

the most common anomaly of the penis (1/300)

Question 30

describe epispadias

Answer 30

• urethra opens on the dorsal surface of penis
• often associated with exstrophy of the bladder

Question 31

the labia minora/vestibule of the vagina are formed both from __________ and ________ (phallic part)

Answer 31

the labia minora/vestibule of the vagina are formed both from ectoderm of the urethral folds and endoderm of the UG sinus (phallic part)

Question 32

the _____ forms the penis in males and clitoris in females

Answer 32

genital tubercle

Question 33

describe ovotesticular DSD (true hemaphroditism)

Answer 33

• rare and is a condition in which the gonads contain both ovarian and testicular tissue
• phenotype may be male or female
• chromosomal configuration usually 46, XX

Question 34

describe 46, XY DSD

Answer 34

• males who produce inadequate levels of testosterone and AMH in utero
• external and internal genital organs vary in appearance due to variable degrees of development

Question 35

describe 46, XX DSD

Answer 35

• females who have been exposed to excessive amounts of androgens in utero = adrenal hyperplasia
  
  • causes masculinization of the external genitalia
• enlargement of clitoris, partial fusion of the labia majora, persistent urogenital sinus

Question 36

describe androgen insensitivity syndrome (AIS)

Answer 36

• individuals who appear female but have 46, XY chromosome configuration
• results from cellular resistance to testosterone
• vagina ends blindly, rudimentary or absent uterus and uterine tubes
• testes present in the inguinal canal
• female breast development at puberty
• external genitalia is female or masculinized

Question 37

describe 5-alpha reductase deficiency

Answer 37

• enzyme is necessary for conversion of testosterone to DHT
  
  • DHT is essential for masculinization of external genitalia
• a deficiency in this enzyme leads to individuals that are genetically male 46, XY (with testes) appear female
  
  • the testes don’t descend initially, but descend later