Reproductive

Question 1

What is chromosomal sex?

Answer 1

Chromosomes of correct complement

Question 2

What is gonadal sex?

Answer 2

Functional testis or ovaries containing germ cells

Question 3

What is phenotypic sex?

Answer 3

Possessing the correct internal and external anatomical male or female genitalia

Question 4

What is behavioral sex?

Answer 4

Demonstrating appropriate sexual behaviour patterns

Question 5

What leads to the male phenotype?

Answer 5

Presence of a functional Y chromosome

Question 6

What about the Y chromosome makes someone male?

Answer 6

SRY (sex determining region of the Y chromosome)

Question 7

Is it always the case that chromosomal sex will give rise to correct gonadal sex?

Answer 7

No

Question 8

What part of mesoderm do the gonads develop from?

Answer 8

Intermediate in region of mesonephros

Question 9

What do gonads initially develop as?

Answer 9

A gonadal ridge

Question 10

What differences between sexes are there when the gonadal ridge first develops?

Answer 10

None

Question 11

Which gene is only switched on in males?

Answer 11

SRY

Question 12

What does the gonadal ridge mesoderm first differentiate into in males?

Answer 12

Coelomic epithelium (mesoderm) covers ridge and forms somatic support cells which then forms Sertoli cells

Sertoli cells lead to differentiation of a testis (AMF and testosterone due to SRY) with testis tubule and interstitial cell formation.

Question 13

What does the gonadal ridge mesoderm (coelomic epithelium) first differentiate into in females?

Answer 13

Granulosa cells which surround the oocytes.

Question 14

What happens to gonadal ridge in 5th week?

Answer 14

Descends into abdomen and reaches it’s final position in 7th week before differentiating

Question 15

What genes are needed for testis formation?

Answer 15

Sox9 of SRY

Question 16

Where do the germ cells develop?

Answer 16

In the embryonic epiblast

Question 17

Where do the primordial germ cells migrate to?

Answer 17

To gonadal ridge via yolk sac and hind gut

Question 18

Describe how testis develop

Answer 18

Primitive germ cells concentrate in medulla (cortex regresses)

Medullary cords develop and contain spermatogonia and Sertoli cells

Leydig cells make testosterone

Question 19

Describe how ovaries develop

Answer 19

No SRY - Primitive germ cells (oogonia) concentrate in cortex, medulla degenerates

Cortex form cortical cords through surface epithelium and primitive sex cords degenerate

Cortical cells differentiate as follicular cells and oogonia proliferate before arresting in prophase

Question 20

What are primitive sex cords?

Answer 20

Structures that develop from the gonadal ridges, in response to germ cells

Question 21

What happens to sex cords in female?

Answer 21

Germ cells send signals to promote differentiation of epithelial cells in gonadal ridge to granulosa cells

Sex cords dissociate so primitive germ cells are in nests (primordial follicles)

Primitive follicles develop but undergo atresia until puberty

Question 22

What happens to testis cords (sex cords)?

Answer 22

Composed of primitive germ cells and Sertoli cells

Forming primitive seminiferous tubules connected to rete testis

Leydig cells differentiate between cords (mesenchyme) (week 7)

Question 23

What do the two ducts originate from?

Answer 23

Paramesonephric (Müllerian) duct

Mesonephric (Wolffian) duct

Question 24

Which duct is retained in females?

Answer 24

Mullerian

Question 25

Which duct is retained in males?

Answer 25

Wolffian

Question 26

What happens to the Mullerian duct in females?

Answer 26

Cranially become fallopian tube Caudally: draws broad ligament across pelvis Other structures from Mullerian duct are oviducts, uterus and cervix

Question 27

What happens to the Wolffian duct in males?

Answer 27

Contacts rete testis Form the epididymis, vas deferens and seminal vesicles

Question 28

Where does the prostate develop from?

Answer 28

Urogenital sinus

Question 29

What hormone is needed to stimulate development of male external genitalia, how is it formed?

Answer 29

5alpha-dihydrotestosterone (DHT) converted from testosterone by the enzyme 5alpha-reductase.

Question 30

Why is 5alpha-dihydrotestosterone (DHT) used over testosterone?

Answer 30

It is more active

Question 31

What is the indifferent stage of the tubes at week 7?

Answer 31

2 ductile system: Wolffian duct Mullerian duct

Question 32

Which duct drains to enter the bladder?

Answer 32

Wolffian

Question 33

Why does the Mullerian duct not drain into the bladder?

Answer 33

It is fused caudally

Question 34

What hormones in males drive the degredation of Mullerian duct and growth of Wolffian duct?

Answer 34

MIF/AMH (anti-mullerian hormone) and MIS secreted by Sertoli cells - Mullerian duct degenerate Testosterone from Leydig cells stimulates growth and differentiation of Wolffian ducts (into epipdymis, vas deferens, ejaculatory duct, seminal vesicles)

Question 35

Why does the Wolffian duct degenerate in females?

Answer 35

No testosterone

Question 36

Describe arrangement of external genatalia in indifferent stage

Answer 36

Genital gubercle divides into genital/urethral folds flanking urogenital sinus all surrounded by genital swelling Urethral groove present

Question 37

When does external genitalia first begin to differentiate and develop?

Answer 37

Week 9

Question 38

How does masculine genitalia differentiate?

Answer 38

Genital tubercle - phallus -penis Urethral folds close urogenital sinus Genital swellings become scrotal swellings Prostate develops

Question 39

How does penile urethra form?

Answer 39

Fusion of urethral folds and canalisation of glands at tip of tubercle

Question 40

Describe how female external genitalia form?

Answer 40

``` Genital tubercle - clitoris Urethral folds - labia minora Urogenital sinus - remains open Genital swellings - major labora Urethral groove remains open between labia minora ```

Question 41

What does the gubernaculum become in females?

Answer 41

From ovary to labora majora, forms round ligament attaching uterus to anterior abdominal wall

Question 42

What is the cortex and medulla of the genital ridge?

Answer 42

Cortex - edge | Medulla - centre

Question 43

In males what separates the developing seminiferous tubules from surface epithelium?

Answer 43

Tunica albuginea

Question 44

In females does anything separate the follicles from germinal epithelium?

Answer 44

No

Question 45

Where are granulosa cells derived from?

Answer 45

Are derived from mesodermal cells of the gonadal ridge

Question 46

What are sertoli cells generated from?

Answer 46

Coelomic epithelium forms somatic support cells which then form Sertoli/ follicular cells

Question 47

What does the endometrium derived from?

Answer 47

Paramesonephric duct

Question 48

How do XY individuals with androgen insensitivity syndrome develop?

Answer 48

Like a female