Sex, Gender and Development

Question 1

What is the definition of someones sex?

Answer 1

• the biological distinction between male and female
• terms male and female describe sexual features, phenotypes

Question 2

Define Gender

Answer 2

• how a person identifies (psychologically) and/or expresses themselves
• set of social beliefs about what it means to be a woman or man vary from one society (culture) to another and over time

Question 3

In which weeks are genital ridges formed from mesenchymal tissue?

Answer 3

3.5-6

Question 4

What are genital ridges formed from?

Answer 4

Mesenchymal tissue

Question 5

Where do primordial germ cells migrate from and to during fetal development of gonads?

Answer 5

Migrate from yolk sac to the connective tisue of the gonadal ridges.

Question 6

What des each gonadal ridge differentiate into?

Answer 6

Sex cords and coelomic epithelium

Question 7

What determines a male sex?

Answer 7

Y chromosome containing Sex determining region of Y chromosome (SRY).

Question 8

The initiation of the formation of the testes depends on the presence of the…

Answer 8

SRY gene (turns on expression of TDF)

Question 9

What does the expression of the SRY gene in sertoli cells cause?

Answer 9

Massive proliferaion of the sex cords.

Question 10

What forms the testis cords?

Answer 10

The sex cords joining with the ingrowing mesonephric ducts (tubules).

Question 11

Seminiferous cords are formed from:

Answer 11

Testis cords joining with PGCs

Question 12

What 3 structures lead to the seminiferous tubules?

Answer 12

PCGs + Prospermatogonia + Sertoli cells

Question 13

What causes the development of the female phenotype?

Answer 13

Failure to form teste and absence of androgen

Question 14

What happens to the coelomic and mesonephric epithelium in the gonad cortex of female?

Answer 14

It condenses, surrounding the PGCs (primordial follicles containing oogonia)

Question 15

Wht do mesenchymal cells secrete and give rise to in the female gonadal development?

Answer 15

Secrete basement membrane and give rise to granulosa cells. Some mesenchymal cells differentiate into theca cells

Question 16

Is the development of the male internal genitalia an active or passive process?

Answer 16

Active, requires endocrine action

Question 17

Why is the SRY gene no longer expressed during the formation of the male internal genitalia?

Answer 17

Testes have resumed the role of sexual differentiation

Question 18

What causes development of the Wolffian duct and external genitalia?

Answer 18

Leydig cells producing androgen

Question 19

What occurs to the Wolffian duct as the testes descend?

Answer 19

Develops into epididymis, vas deferens, and seminal vesicles.

Question 20

What causes the degeneration of the Mullerian ducts in males?

Answer 20

Sertoli cells secreting Anti-Mullerian Hormone (AMH)

Question 21

What causes the development of the Mullerian duct?

Answer 21

Absence of Androgen and anti-mullerian hormone

Question 22

What does the mullerian duct develop into?

Answer 22

Oviducts, Uterus, Cervix, Upper vagina

Question 23

What is Turner syndrome?

Answer 23

An embryo w/ 45 chromosomes, only one X, no Y. Normal autosomal complement.

Question 24

What occurs to development of reproductive characteristics during Turners syndrome? Why?

Answer 24

Formation of Ovaries + External Female genitalia

Absence of SRY-> No testes -> no AMH -> Mullerian grow, Wollfian regress.

Presence of only one X = Death of oocytes and ovarian dysgenesis. = Infertile.

Question 25

What is Klienfelter syndrome?

Answer 25

An embryo w/ 47 chromosomes, Two XX oneY

XXY.

Normal autosomal complement

Question 26

What occurs to development of reproductive characteristics of someone with Kleinfelters syndrome? Why?

Answer 26

Y chromosome = Testes formation

Testosterone = Wolffian duct formation

AMH =Mullerian duct degeneration

Male exernal genitalia.

Two XX chromosomes = Death of germ cells (hyperactivity). Exocrine testes dysgenesis = Infertile

Question 27

What occurs to development of reproductive characteristics for someone with removed gonads of normal male and female fetuses.

Answer 27

• No gonads (removed)
• Both develope female internal and external genitalia.

Castrated female genotype (Like Turners) for both = Infertile

Question 28

What is Testicular Feminisation?

Answer 28

Androgen Insensitivity Syndrom (AIS)

Normale MALE XY genotype

Both Wolffian and bipotential tissues of external gentialia are insensitive to androgen (Lack effective receptors)

Question 29

What would happen to the development of sexual genitalia in individuals with Testicular feminisation

Answer 29

• Normal Testes, Androgen, AMH (Sertoli)
• Regression of both Wolffin and Mullerian ducts- no internal organs
• Normal Female external genitalia
• Genetically Male but phenotypically Female
• Genetically fertile but in practice, infertile

Question 30

What is androgenital syndrome?

Answer 30

Congenital Andrenal Hyperplasia(CAH)

Normal XX female genotype

Hyperactive adrenal gland = high androgen levels

Question 31

Ehat would happen to genital development in someone with Andrenogenital Syndrome?

Answer 31

• Normal Ovaries
• Normal Wolffian and Mullerian ducts (no AMH), both internal organs
• Bipotential tissue responds to testosterone = normal male genitalia
• Genetically female baby w/ male external genitalia

Genetically fertile, but in practice, infertile.