Development Of The Genital System

Question 1

How long is the gonad identical in male & female

Answer 1

Till the 7th week of development

Question 2

Where do primordial germ cells migrate to in the 6th week

Answer 2

Genital ridges

Question 3

What develops medial to the mesonephric ridge

Answer 3

Genital ridge

Question 4

What is paramesonephric duct aka

Answer 4

Mullerian duct

Question 5

What is the mesonephric duct aka

Answer 5

Wolffian duct

Question 6

As primordial germ cells arrives what happens to form primitive sex cords

Answer 6

Epithelium invades the mesenchyme

Question 7

What genes drive testes development

Answer 7

SRY and SOX9

Question 8

During sex differentiation, what duct degenerates in a) males and b) females and give the substance responsible

Answer 8

a) paramesonephric duct degenerates - anti- mullerian hormone
b) mesonephric duct regresses - oestrogen

Question 9

What genes drive female development

Answer 9

Absence of SRY
SOX9 is inhibited
WNT4 is crucial for ovarian development

Question 10

Under the influence of testis determining factor, what do the primitive sex cords form

Answer 10

Develop and Form the testis cords

Question 11

Which 2 cells are the testis cords composed of

Answer 11

Sertoli cells - develop from the surface epithelium if the gonad
Primordial germ cell

Question 12

What does the mesenchyme in the gonadal ridge give rise to

Answer 12

Leydig cells which lie between the cords

Question 13

When do leydig cells start producing testosterone

Answer 13

8th week

Question 14

What happens to primitive sex cords in females

Answer 14

They regress

Question 15

What does the surface epithelium give rise to in females and what do they do

Answer 15

Cortical cords

They invade the mesenchyme and split it into clusters of cells which surround each germ cell

Question 16

What 2 things give rise to the primordial follicle

Answer 16

Germ cell and surrounding follicular cells

Question 17

How do the testes descend into the pelvis

Answer 17

Through deep ring, inguinal canal and superficial ring

Question 18

What happens to the canal between the processus vaginalis and peritoneal cavity around birth

Answer 18

It closes

Question 19

During ovary descent to the pelvis, where does the round ligament run

Answer 19

In the inguinal canal to the labia majora

Question 20

What does the paramesonephric duct open into

Answer 20

The abdominal cavity at its rostral end

Question 21

What occurs at the caudal end of the Müllerian duct as they develop

Answer 21

Caudal ends meet in the midline and project into the urogenital sinus

Question 22

Where does the mesonephric duct open into

Answer 22

Urogenital sinus

Question 23

in males, the distal ends of the mesonephric duct opens into the urogenital sinus to form……

Answer 23

Ejaculatory ducts - prostate develops around it

Question 24

What produces anti Müllerian hormone

Answer 24

Sertoli cells

Question 25

Where does the upper vs lower part of the vagina develop from

Answer 25

Upper - Paramesonephric ducts

Lower - urogenital sinus

Question 26

What are the 4 main structures of an undifferentiated external genitalia

Answer 26

Genital tubercle
Urethral folds
Urethral groove
Genital swelling

Question 27

Under the influence of oestrogen, what do the 4 undifferentiated external genitalia structures become

Answer 27

Genital tubercle - clitoris
Urethral folds - labia minora
Urethral groove - vestibule
Genital swellings - labia majora

Question 28

Under the influence of testosterone, what do the 3 undifferentiated external genitalia structures become

Answer 28

Genital tubercle - penis
Urethral folds - fuse together and form penile urethra
Genital swellings - scrotum