Session 1

Question 1

Where is the Urogenital ridge?

Answer 1

By the posterior abdominal wall of the embryo

Question 2

What tissue makes up the Urogenital ridge?

Answer 2

Intermediate mesoderm

Question 3

What forms the gonad in the embryo?

Answer 3

Intermediate mesoderm of the Urogenital ridge and primordial germ cells

Question 4

What do the primordial germ cells have in males only?

Answer 4

The Y chromosome

Question 5

What drives the development of the male in embryos?

Answer 5

The hormone SRY

Question 6

What does SRY drive the development of in male embryos?

Answer 6

Gonad (Testis)
Internal genitalia (Duct system)
External genitalia

Question 7

What part of the indifferent gonad develops into the testis in embryos?

Answer 7

The medulla

Question 8

What causes the development of a female embryo?

Answer 8

Absence of the Y chromosome

Question 9

What part of the indifferent gonad develops into the ovaries in embryos?

Answer 9

The cortex

Question 10

What is the other name for Mesonephric ducts?

Answer 10

Wolffian ducts

Question 11

What is the other name for Paramesonephric ducts?

Answer 11

Mullerian ducts

Question 12

What makes the Mesonephric ducts remain in the embryo?

Answer 12

Androgens

Question 13

What happens to the Mesonephric ducts if there are no androgens present?

Answer 13

It regresses

Question 14

What forms the Urogenital sinus?

Answer 14

Created from hindgut by the urorectal septum

Question 15

How do the Paramesonephric ducts develop?

Answer 15

Appear as invaginations of the epithelium of the urogenital ridge

Question 16

What makes the Paramesonephric ducts develop?

Answer 16

Develop either way, do not need anything to maintain them

Question 17

How is the uterus and fallopian tubes formed?

Answer 17

The 2 Paramesonephric ducts grow towards one another and fuse to form them

Question 18

How is the vagina and hymen formed?

Answer 18

The urogenital sinus tissue expands to make a vaginal plate which then forms the vagina and hymen

Question 19

What does the testis secrete to prevent the Paramesonephric duct from developing?

Answer 19

Mullerian inhibiting substance (Hormone)

Question 20

Why do the Mesonephric ducts regress in females?

Answer 20

There are no testis to release androgens to support the Mesonephric ducts

Question 21

What are the 3 basic components of the indifferent stage in development of the external genitalia?

Answer 21

Genital tubercle
Genital folds
Genital swelling

Question 22

What is the outline of the urogenital sinus?

Answer 22

The genital folds

Question 23

In male embryos, what does the Genital tubercle and genital folds become?

Answer 23

The Genital tubercle elongates and fuses with the genital folds to become the spongy urethra

Question 24

What does the genital swelling become?

Answer 24

Folding of it leads to development of the scrotum

Question 25

What influences the development of the spongy urethra?

Answer 25

Testis derived androgen hormones, specifically Dihydrotestosterone

Question 26

Why is there no fusion in the female urethra?

Answer 26

There is no Dihydrotestosterone present so no fusion occurs and the urethra opens into the vestible

Question 27

How does the descent of the testis occur?

Answer 27

They are attached to the posterior abdominal wall via the Gubernaculum ligament.
As the abdomen elongates, the ligament shortens so the testis move to behind the processes vaginalis
It takes its ducts and lymphatics with it

Question 28

What does the testis pass through during its descent?

Answer 28

Deep inguinal ring into the inguinal canal to the scrotum

Question 29

How does the descent of the ovaries occur?

Answer 29

Gubernaculum ligament attaches the ovary inferiorly to the labro-scrotal folds. The ovary descends into the pelvis via the inguinal canal

Question 30

What ligament is in the inguinal canal?

Answer 30

The round ligament on the uterus