Reproduction 1 - introduction

Question 1

What is the gene on the Y chromosome that determines whether a testes or ovary will be made

Answer 1

SRY gene - sex determining region Y (or testes determining factor) - this is a TF and main target is SOX9 gene

Question 2

How many X chromosomes are required for normal ovary production

Answer 2

2

Question 3

If you have only 1 x chromosome what happens to the ovaries

Answer 3

no gonads at all, just fibrous tissue

Question 4

what do mesenchymal cells develop into

Answer 4

androgen producing cells (does not happen in ovaries)

Question 5

When do primordial germ cells migrate to gonadal ridge

Answer 5

5-6 weeks into gestation

Question 6

Is the primordial gonad specific to testes or ovary generation

Answer 6

no

Question 7

What drives expression of testes

Answer 7

SRY and SOX9

Question 8

what drives expression of ovaries

Answer 8

lack of SRY

Expression of RSPO1 and WNT4

Question 9

RSPO1

Answer 9

testes repressor

Question 10

Gametes and reproductive cells intestes

Answer 10

Gamete-sperm
Reproductive cells- sertoli cells
leydig cells

Question 11

Gametes and reproductive gonad cells in ovaries

Answer 11

Gametes are ova, then you have follicular cells which can be broken into granulosa and thecal cells. The gametes and ova together make the follicle

Question 12

What do sertoli cells secrete in development that helps drive male gonadal development

Answer 12

antimullerian hormone

Question 13

Leydig cells - what do they secrete that will help drive male gonad production

Answer 13

Testosterone - converted in peripheral tissues via DHT via 5-alpha-reductase or estrogens via aromatase

Question 14

What two things make up a follicle

Answer 14

follicular cells and gamete (ova)

Question 15

Two types of follicular cells

Answer 15

Granulosa cells, thecal cells

Question 16

what do granulosa cells make that is important for maturation of gametes

Answer 16

estrogens and progesterone

Question 17

DHT role in male gonad development

Answer 17

External male genetalia

Question 18

Testosterone role in male genetial/gonad development

Answer 18

internal male genetalia (wolffian duct)

Question 19

How do testes induce regression of mullerian duct

Answer 19

secretion of AMH and inhibin B

Question 20

How do testes induce generation of male internal and external genetalia

Answer 20

Leydig cells produce testosterone and DHT, which form male internal genetalia from Wolffian duct (top - epididymis, middle, ductus deferens, base is seminal vesicle and ejaculatory duct). DHT will also help form prostate and external genetalia

Question 21

What part of primordial gonad becomes internal male genetalia

Answer 21

medulla

Question 22

What induces regression of wolffian ducts?

Answer 22

absence of testes (NOT presence of ovary) – no AMH, no androgens.

Question 23

how do mullerian ducts differentiate

Answer 23

top - fallopian tubes
middle- fuses to become uterus
bottom-cervix and upper 1/3 of vagina

Question 24

What is internal vs external genetalia for vagina

Answer 24

upper 1/3 - internal genetalia

bottom 2/3 - external genetalia

Question 25

What part of the primordial gonad develops into internal female genetalia

Answer 25

cortex

Question 26

urogenital sinus

Answer 26

ventral part of cloacca. In males, separated into 3 regions that develop into bladder, prostatic urethra, and penile urethra. In females, common opening splits into lower 2/3 of vagina and urethra.

Question 27

Penis, scrotum, and prostate all require what to develop?

Answer 27

DHT

Question 28

Taking what hair medication might inhibit male external development, and why?

Answer 28

Propecia - it inhibits 5-alpha reductase, so you don't get formation of external genetalia (no DHT)

Question 29

When male germ cells divide how many do we end up with at end of meiosis II?

Answer 29

4

Question 30

When female germ cells divide how many do we end up with at end of meiosis II

Answer 30

1

Question 31

In females does mitosis of germ cells continue after birth?

Answer 31

nope

Question 32

Female production of germ cells

Answer 32

no mitosis after birth, jsut have primary oocytes at diploid stage and arrested halfway through meiosis I until puberty when you resume meiosis I. Then you get haploid cells that are arrested but instead of splitting into 2 we get 1 polar body and just goes away. Then you get meiosis 2 arrested halfway through until fertilization.

Question 33

Disorders of sexual determination - what would this be?

Answer 33

sex chromosome aneuploidy (like turner syndrome, XO, or klinefelter syndrome (XXY )

Question 34

Disorders of gonadal dysgenesis would be what?

Answer 34

abnormal testes formation in utero - like androgen resistance due to loss of x linked androgen receptor

Question 35

Disorders of sexual differentiation would be what?

Answer 35

Defects in internal and/or external genetalia like enzyme deficiencies or androgen excess.

Question 36

What kind of categories of disorders of sexual development can gonadal dysgenesis be seen in?

Answer 36

all of them

Question 37

Turner syndrome - genotype, results

Answer 37

XO ``` Streak gonad (cannot form full ovary) No AMH (no testes) - so well developed mullerian duct, you do have female internal genetalia. No testes, so no testosterone - regressed wolfian duct due to no testosterone to develop Phenotypically we have no DHT, so female external genetalia ```

Question 38

Klinefelter syndrome - genotype, results

Answer 38

nondisjunction in meiosis leads to XXY Dysgenetic testes - you get RSPO1 which is a testes repressor, so even though you have Y chromosome you get fighting between X's and Y's. However, usually you still get a regressed mullerian duct and developed wolffian. But the result of testes will be quite fibrous

Question 39

Loss of androgen receptor - genotype, cause, result

Answer 39

X chromosome has the androgen receptor - if receptor is not present, body cannot respond to androgens. Therefore you have no female internal genetalia, testosterone made by leydig cells though will not give internal male genetalia, either - so you get no internal genetalia at all. External genetalia will be female (no androgen recetpor)

Question 40

Loss of 5-alpha reductase - genotype, cause

Answer 40

Chromosomal XY - testes will have AMH being formed so regression of mullerian duct. Testosterone is made, so wolfian duct will develop. But testosterone will not make DHT, so genetalia will not form properly. Ambiguous - testosterone causes cliteromegaly so it will look like penis is forming but no penis, prostate, or scrotum fully develops Can also be caused by exposure to propecia

Question 41

What are some other symptoms of turner syndrme?

Answer 41

Phenotypic issues due to aneuploidy like webbed neck, lymphedema, low set ears, wide set nipples, cubitus valgus).

Question 42

What are some other telltale symptoms of klinefelter syndrome

Answer 42

Testosterone is low, micropenis, eunuchroid body, lower segment is greater than upper segment by more than 2 inches but slhort arms. Gnecomastia as well due to elevated estradiol and breast development. Systemic phenotypic issues due to aneuploidy. These individuals will also be infertile

Question 43

In individuals with complete androgen resistance what are hormone levels like?

Answer 43

androgens high (lack of feedback), estrogen levels high (for male). Gonadotropins are high which stimulates more and more androgen production and this will be converted into estrogen since androgen receptors don't work. Phenotype is female with blind pouch vagina. High high estrogens and induction of female characteristics. NO internal genetalia, like, at all

Question 44

Gonadal dysgenesis - genotype, reasons, result

Answer 44

XX karyotype but possible SRY translocation or loss of RSPO1 gene. No spermatogenesis because other Y chromasome genes not present, ambiguous genetalia, urethra does not exit in proper location

Question 45

What can be a result of taking contraceptives in pregnancy

Answer 45

Virilization of female XX genotype due to excess ndrogens