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)

1. Chromosomal Determination

XX or XY

2. Gonadal Determination

Ovary or testes

3. Phenotypic determination

What do sex organs look like

1. Chromosomal DeterminationOvum

22 Autosomes

1 X chromosome

Sperm

22 Autosomes

1 X chromosome

or

1 Y chromosome

Zygote = 46 XX

or

46 XY

Cleavage

Blastocyst

Implantation

Formation of the Placenta

Primordial Germ Cells

3 Week Embryo

6 Weeks embryo

6 weeks

At Six Weeks

Primordial Germ Cells

Genital/GonadalRidge

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

Gonadal

Ridge

Mullerian Duct

Wolffian Duct

Gonadal Ridge

Mullerian Duct

Wolffian Duct

Epidydidimis

Vas deferens

Degenerating Mullerian Duct

Seminal Vesicle

Ovaries

Uterus

Fallopian Tubes

Upper Part of Vagina

Undifferentiated external

Genital tubercle

Genital foldGenital groove

Labioscrotal swelling

Undifferentiated external

Genital Tubercle

Genital Fold

Genital Groove

Labioscrotal Swelling

Undifferentiated Stage

Genital Tubercle

Genital Fold

Genital Groove

Labioscrotal Swelling

Genital Tubercle

Glans Penis

Genital Fold

Genital Groove

Labioscrotal Swelling

Penile Rafe

Urethra

Scrotal Sac

Genital Tubercle

Clitoris

Genital Fold

Labia Minor

Genital Groove

Labioscrotal Swelling

Labia Major

Vaginal and Urethral Opening

7 Months 8 Months

Transabdominal movement

Formation of the Inguinal Canal

Movement into scrotal sac

1. Gubernaculum

2. Phallus

3. Inguinal Canal

4. Testes

5. Abdominal cavity

6. Vas deferens

Masculanize the Wolffian Duct

Testosterone

Masculanize the external genitals

Masculanize the Brain