Embryology of the Reproductive Organs The entire process of sexual development depends on a sequential series of interactions between regulatory factors and genetic machinery.

Stages of Sexual Determination (Differentiation) Chromosomal Determination XX or XY Gonadal Determination Ovary or testes Phenotypic determination What do sex organs look like

1. Chromosomal Determination Ovum 22 Autosomes 1 X chromosome Sperm 22 Autosomes or 1 Y chromosome Zygote = 46 XX 46 XY

Cleavage

Blastocyst

Implantation

Formation of the Placenta

Primordial Germ Cells

3 Week Embryo

6 Weeks embryo

6 weeks

Primordial Germ Cells Genital/GonadalRidge At Six Weeks

TDF

Testes Determining Factor TDF is a gene on the Y chromosome that converts the Gonadal/Genital ridge to a testes Inside a testes you have: Seminiferous tubules – Spermatogonia inside Sertoli cells – Produces MIF (Mullerian inhibiting Factor in embryo. Interstitial cells – Produce Testosterone

Mullerian Duct Gonadal Ridge Wolffian Duct

Gonadal Ridge Mullerian Duct Wolffian Duct

Epidydidimis Vas deferens Degenerating Mullerian Duct Seminal Vesicle

Ovaries Fallopian Tubes Uterus Upper Part of Vagina

Undifferentiated external Genital tubercle Genital groove Genital fold Labioscrotal swelling

Undifferentiated external Genital Tubercle Labioscrotal Swelling Genital Fold Genital Groove

Undifferentiated Stage Genital Tubercle Genital Fold Genital Groove Labioscrotal Swelling

Genital Tubercle Genital Fold Genital Groove Labioscrotal Swelling Glans Penis Penile Rafe Urethra Scrotal Sac

Genital Tubercle Genital Fold Genital Groove Labioscrotal Swelling Clitoris Labia Minor Vaginal and Urethral Opening Labia Major

7 Months 8 Months

Transabdominal movement Formation of the Inguinal Canal Movement into scrotal sac

Gubernaculum Phallus Inguinal Canal Testes Abdominal cavity Vas deferens

Masculanize the Wolffian Duct Testosterone

Masculanize the external genitals

Masculanize the Brain