reproduction 4 - sexual determination and differentiation

Question 1

what is the jost paradigm

Answer 1

that the types of sex chromosomes determines sex, which determines gonads, which detemines the genital/phenotypic sex

Question 2

when is chromosomal sex determined

Answer 2

at the exact moment of fertilization

Question 3

how is gonadal sex determined

Answer 3

chromosomal sex

Question 4

what causes the differentiation of bipotential gonads to become testes

Answer 4

SRY genes on Y chromosome

Question 5

what does bipotential gonad mean

Answer 5

the structure can go either wat

Question 6

what disorder is XXY

Answer 6

klinefelters syndrome

Question 7

what happens in XXY to spermatogenesis

Answer 7

it is imparited

Question 8

what causes the differentiation of bipotential gonads to become ovaries

Answer 8

the absense of the Y chromosome

Question 9

what disorder is XO

Answer 9

turners syndrome

Question 10

what are streak ovaries

Answer 10

much smaller ovaries with follicles embedded with connective tissue

Question 11

what does MIH do

Answer 11

causes regression of the mullerian duct, thereby regression of female internal genetalia

Question 12

do males have MIH

Answer 12

yes

Question 13

where do males secrete MIH

Answer 13

the testes secrete it from sertoli cells

Question 14

do females have MIH

Answer 14

no

Question 15

where is testosterone secreted

Answer 15

leydig cells

Question 16

what does testosterone cause the development of

Answer 16

male internal genetalia (seminal vesicle, testes, vas deferens, epididymis, and ejaculatory duct)

Question 17

where does DHT come from

Answer 17

T is converted into DHT

Question 18

what does DHT cause the development of

Answer 18

masculinazation of male penis+prostate gland + scrotal sac

Question 19

which hormones causes the masculinazation of male external genetalia

Answer 19

DHT

Question 20

which hormones causes the development of male internal genetalia

Answer 20

testosterone

Question 21

what causes the development of the wolffian duct in females

Answer 21

absense of testosterone

Question 22

what causes the absence of masculinization of external genetelia in females

Answer 22

absense of DHT

Question 23

what causes the mullarian duct to grow into female internal genitalia

Answer 23

absense of MIH

Question 24

which sex has their differentiation happening by “default”

Answer 24

female

Question 25

do men have wolfian duct

Answer 25

yes

Question 26

do men have mullerian duct

Answer 26

no

Question 27

do women have mullerian duct

Answer 27

yes

Question 28

do women have wolfian duct

Answer 28

no

Question 29

what does the mullarian duct become

Answer 29

uterus, oviducts, etc

Question 30

what does the wolffian duct become

Answer 30

epididymis, vas deferns, seminal vesicles, ejaculatory duct

Question 31

when do the 3 peaks of testosterone happen

Answer 31

fetal (2nd trimester) neonatal (before 1y/o) puberty and declines till death

Question 32

what is genotype and phenotype of congenital adrenal hypoplasia

Answer 32

XX, ovaries, looks male

Question 33

what causes congenital adrenal hypoplasia

Answer 33

decreased cortisol ism ade b/c mutation --> HPA makes more ACTH (no -ve feedback from cortisol) --> cholesterol makes andreogens instead of cortisol --> causes masculinization of external genetalia

Question 34

are poeple with congenital adrenal hypoplasia fertile

Answer 34

nope

Question 35

what is the genotype and phenotype of androgen insensitivity syndrome

Answer 35

XY, testes, outwardly looking female

Question 36

what causes androgen insensitivity syndrome

Answer 36

yes they have MIH so no female internal, but the cells on the Wolffian duct do not respond to T so no internal male structures also the cells dont repond to DHT so by default they have external female structures

Question 37

are people with androgen insensitivity syndrome fertile

Answer 37

no

Question 38

what causes complete androgen insensitivity syndrome

Answer 38

mutation on androgen receptor

Question 39

what triggers the onset of puberty

Answer 39

increased GnRH which causes increased LH and FSH

Question 40

what is the hypothalamic - pituitary - gonadal axis like in young prepubertal children

Answer 40

dormant, very sensitive to negative feedback, low levels of GnRH, LH, FSH and sex steroids

Question 41

what causes the activation of the hypothalamic - pituitary - gonadal axis

Answer 41

kisspeptin

Question 42

what does kisspeptin do

Answer 42

postively activates the hypothalamus to released GnRH in pulses, then the ant. pit releases more LH and FSH to the gonads to make sex steroids

Question 43

why do chubby girls get puberty earlier

Answer 43

leptin causes the release of kisspeptin

Question 44

why do very athletic girls get puberty earlier

Answer 44

no fat so slower/ delayed release of kisspeptin

Question 45

what is climacteric

Answer 45

the phase before menopause where periods are becoming less frequent and regular

Question 46

what is menopause and what causes it

Answer 46

no more period because no more follicles

Question 47

what is andropause

Answer 47

less testosterone and spem production, linked to depression

Question 48

when do women reach perimenopause (how many follicles left)

Answer 48

1000

Question 49

what happens to responsiveness to gonadotropins in menopause and what does this cause

Answer 49

decreased responsiveness which causes decreased estrogen and inhibit release from granulosa cells

Question 50

what happens to FSH and LH in menopause and why

Answer 50

decrease E inhibin and P removes negative feedback on FSH(!) and LH, so they increase

Question 51

what happens to FSH:LH ratio in menopause

Answer 51

increase | less -ve feeback holding back both, FSH most affected

Question 52

what are some problems that may arise due to low estrogen

Answer 52

heart problems (E keeps heart healthy) and osteoperosis