Embryology of Female Tract

Question 1

Mullerian (paramesonephric ducts) structures

Answer 1

Form uterus, uterine tubes, cervix, upper part of vagina

Requires estrogen and WNT4

Question 2

Development of Female Gonads

Answer 2

Week 5: primordial germ cells migrate to genital ridge WNT4: ovary determining gene

• Germ cells start gametogenesis and arrest in ProI
• Germ cells induce formation of follicular cells
• WNT4–>DAX1, which inhibits SOX9 (stops development of testes)

Estrogen:

1. stimulates migration of paramesonephric ducts
2. stimulates formation of female external genitalia

Question 3

Paramesonephric Duct fusion

Answer 3

Corms uterus, upper part of vagina

Unfused portion forms uterine tubes

Lower part of vagina from urogenital sinus (also bladder, urethra)

Gubernaculum attempts to push ovary through inguinal canal but broad ligament prevents this–> remnant becomes round ligament of uterus

Question 4

Improper PM Duct Fusion

Answer 4

Bicornuate uterus

Question 5

External Genitalia Formation

Answer 5

Glans area: clitoris

Genital swelling: shaft of clitoris

Urogenital fold: remains unfolded, forms boundaries of vestibule– labia minora