Development of the Reproductive System

Question 1

Describe the development of the testes

Answer 1

Indifferent gonad from the intermediate mesoderm

SRY gene on Y chromosome produces testis-determining factor which promotes testicular development

Question 2

Describe the development of the ovaries

Answer 2

Indifferent gonad from the intermediate mesoderm
Default is to differentiate into ovary
No SRY gene - no testicular development

Question 3

Describe the formation of the Fallopian tubes

Answer 3

Paramesonephric ducts develops from urogenital ridge
Grow towards each other and fuse in the midline
Forms uterus and upper 1/3 of vagina

Paramesonephric ducts maintained due to absence of anti-Mullerian hormone

Question 4

Describe the formation of the vas deferens

Answer 4

Testosterone from Leydig cells maintains mesonephric ducts
Sertoli cells produce anti-Mullerian hormone causing paramesonephric ducts to regress
Mesonephric ducts become the vas deferens

Question 5

Which cells produce anti-Mullerian hormone?

Answer 5

Sertoli cells

Question 6

Which male structures are derived from the mesonephric ducts?

Answer 6

Vas deferens
Epididymis
Seminal vesicles
Prostatic utricle

Question 7

Describe the formation of the vagina

Answer 7

Fused paramesonephric ducts attach to urogenital sinus
Upper third of the vagina is derived from paramesonephric ducts
Lower two thirds of the vagina are derived from the urogenital sinus

Question 8

At how many weeks of gestation does differentiation of external genitalia occur?

Answer 8

10 weeks’ gestation

Question 9

What are the three key parts to the undifferentiated external genitalia?

Answer 9

Genital tubercle
Genital folds
Genital swellings

Question 10

Describe the formation of male external genitalia

Answer 10

Due to testosterone
Genital tubercle elongates to form the glans
Genital folds fuse to form the spongy urethra and shaft of the penis
Genital swellings form the scrotum

Question 11

Describe the formation of the female external genitalia

Answer 11

Absence of testosterone
Genital tubercle forms the clitoris
Genital folds form the labia minora
Genital swelling forms the labia majora