Genitalia Development

Question 1

Intermediate Mesoderm Contributions

Answer 1

Nephrogenic Cord
Urogenital Ridge
Mesonephric Duct
Paramesonephric Duct
Leydig Cells
Thecal Cells

Question 2

Epiblast Contributions

Answer 2

Primordial Germ Cells

Oocytes and Spermatogonia

Question 3

Coelomic Epithelium (Somatic Support Cells)
Contributions and Germ Layer Type

Answer 3

Somatic Lateral Plate Mesoderm

Makes Sertoli and Follicular Cells

Question 4

SRY Gene Functions Male

Answer 4

Switch that turns on male differentiation cascade

Increases Leydig and sertoli cells and increases testis determining factor

Question 5

Leydig Cell Sex Differentiation Function

Answer 5

Increases testosterone so mesonephric duct stays
causes male internal genitalia formation
causes increased DHT that induces male external genitalia

Question 6

Sertoli Cell Sex Differentiation Function

Answer 6

Increases Anti-Mullerian Hormone so paramesonephric duct degenerates
stops female internal genitalia formation

Question 7

SRY Gene Function Female

Answer 7

SRY is ABSENT in females
Leads to Thecal cells that cause mesonephric degeneration
Leads to Follicular cells that cause paramesonephric persistence

Question 8

Urogenital Ridge Contributions

Answer 8

Primary Gonadal Cords
Testes
Ovaries

Question 9

Paramesonephric Duct

Female Derivatives and Germ Layer Type

Answer 9

Broad L. of Uterus
Uterine Tubes
Fuses to become uterovaginal primordium
   Uterus (caudal end)
   Upper 1/3 of Vagina (cranial end)

Intermediate Mesoderm

Question 10

Urogenital Sinus 
Female Derivatives (6) and Germ Layer Type

Answer 10

Membranous Urethra
Urethral Glands
Paraurethral Glands
Greater/Lesser Vestiublar Glands
Lower 2/3 of Vagina 
Vaginal Vestibule

Hindgut Endoderm

Question 11

Vagina Development with Germ Layers

Answer 11

Uterovaginal Primordium (mesoderm) connects with urogenital sinus (endoderm) to form sinus tubercle
Induces formation of sinovaginal bulbs
Bulbs fuse to form vaginal plate
Plate undergoes recanalization to form vagina

Question 12

Mesonephric Duct

Male Derivatives and Germ Layer Type

Answer 12

Appendix of Epididymis
Ductus Deferens
Seminal Vesicles
Ejaculatory Duct

Intermediate Mesoderm

Question 13

Mesonephric Tubules

Male and Female Derivatives

Answer 13

Male: Efferent Ductules

Female: epoophoron, paroophoron

Question 14

Urogenital Sinus
Male Derivatives (5) and Germ Layer Type

Answer 14

Urinary bladder
Prostatic Urethra
Membranous Urethra
Prostate Gland
Bulbourethral Glands

Hindgut Endoderm

Question 15

Navicular Fossa Formation

Answer 15

Surface ectoderm forms urethral plate in tip of spongy urethra
Recanalization forms fossa

Question 16

Genital Tubercle

Male and Female Derivatives

Answer 16

Glans Penis

Glans Clitoris

Question 17

Urogenital Folds

Male and Female Derivatives

Answer 17

Male: Lateral wall urethra, Spongy urethra, Penile raphe

Female: Labia minora frenulum

Question 18

Labioscrotal Swellings

Male and Female Derivatives

Answer 18

Scrotum

Labia Majora

Question 19

Ovarian and Uterine Ligaments Formation

Answer 19

Suspensory L. of Ovary from Cranial Gubernaculum

Round L. of Uterus from Caudal Gubernaculum

Broad L. of Uterus from Paramesonephric Duct

Question 20

46 XY DSD

Answer 20

Has testes but phenotypically female

Caused by decreased testosterone, AMH or androgen insensitivity, 5-alpha reductase deficiency
Androgen insensitivity will cause blind end vagina and normal breast development but no utuers/menstruation

Question 21

46 XX DSD

Answer 21

Has ovaries but masculinized external genitalia
Fused labia, clitoral hypertrophy and persistent urogenital sinus

Caused by excess androgen exposure to female fetus

Question 22

Hypospadias

Type and Description

Answer 22

Glanular: incomplete urogenital fold fusion or navicular fossa solid

Penile: incomplete urogenital fold fusion

Penoscrotal: incomplete labioscrotal swelling fusion

Question 23

Epispadias Description

Answer 23

Improper genital tubercle location with estrophy of bladder