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Flashcards in reproductive endocrinology Deck (49)
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1
Q

testosterone (the primary male sex hormone) is an __________

A

androgen

2
Q

_________ is more potent than DHEA or androstenedione

A

testonsterone

3
Q

what are the 2 primary female sex hormones? what class of hormone are they?

A

1) estradiol- an estrogen

2) progesterone- a progestin

4
Q

how is estradiol produced?

A

from testosterone by AROMATASE

5
Q

when is progesterone the primary female sex steroid?

A

during part of the menstrual cycle and during pregnancy

6
Q

the secretion of GnRH is _________

A

pulsatile- due to control by neuroendocrine system

7
Q

continuous, nonpulsatile GnRH will inhibit _____ and _____ secretion

A

FSH and LH secretion

8
Q

gonadal hormones have negative feedback actions on both _______ and ________

A

GnRH and LH/FSH

9
Q

during what time does GnRH stimulate LH and FSH in women?

A

ovulation

10
Q

the positive feedback action of ______ controls ovulation in females

A

estrogen

11
Q

what cells synthesize testosterone in response to LH in males?

A

leydig cells

12
Q

__________ cells line the seminiferous tubules

A

sertoli cells

13
Q

what are the functions of the sertoli cells?

A

1) regulate spermatogenesis
2) produce androgen binding protein (ABP)- sequesters testosterone in testis
3) secrete inhibin- regulates FSH secretion
4) secrete tubular fluid
5) aromatize testosterone into estradiol

14
Q

testosterone has a negative feedback action on _____ and ______

A

GnRH and LH

15
Q

what does inhibin reduce?

A

production of FSH

16
Q

what enzyme converts testosterone to DHT?

A

5-alpha-reductase

17
Q

what molecule acts on hair follicles, and can cause baldness in men?

A

DHT (dihydrotestosterone)

18
Q

oocytes are arrested in _________. what are they enclosed in?

A

arrested in meiosis 1

enclosed in a follicle

19
Q

what cells of the ovary produce testosterone/androstenedione (androgens) in response to LH?

A

theca cells

20
Q

what is the function of the granulosa cells in the ovary?

A

aromatize androstenedione (androgens) into estradiol in response to FSH

also produce inhibin

21
Q

the theca cells synthesize ___________ in response to LH

A

androstenedione

22
Q

granulosa cells convert the androstenedione into ______

A

estradiol

23
Q

while the ovarian follicle is developing, ______ inhibits both GnRH and LH

A

estradiol

24
Q

what are the 2 phases of the ovarian cycle?

A

folicular and luteal

25
Q

_____ will cause a surge of gonadotropins during the ovarian cycle, causing ovulation

A

estrogen

26
Q

when does the ovarian cycle begin?

A

begins with menstrual flow when CL regresses

27
Q

t/f: during the ovarian cycle, estrogen will stimulate the proliferation of the endometrium

A

true

28
Q

the corpus luteum will regress when _____________ levels are too low

A

gonadotropins

29
Q

if pregnancy occurs, the placenta will produce what hormone?

A

human chorionic gonadotropin (hCG)

30
Q

what is the function of hCG?

A

maintains luteal steroidogenesis until the placenta fully develops

31
Q

after menopause, the body must rely on _________ androgens

A

adrenal

32
Q

what 2 hormones are elevated after menopause? why is this?

A

LH and FSH are very high

there is no negative feedback placed on them anymore

33
Q

the physiological consequences of menopause are mostly due to what?

A

decreased estrogens

34
Q

what are the 2 ducts/tubules associated with undifferentiated gonads? which remains in women? in men?

A

mullerian and wolffian ducts

men- wolffian ducts remain
women- mullerian ducts remain

35
Q

what are the 2 hormones produced by fetal testes that regulate the differentiation of the wolffian ducts?

A

testosterone (stimulated proliferation of wolffian ducts)

mullerian inhibiting substance

36
Q

a lack of _________ causes the regression of the wolffian duct system

A

testosterone

37
Q

what causes congenital adrenal hyperplasia?

A

results from a mutation in steroidogenic enzymes

38
Q

what is the genotype of someone suffering from congenital adrenal hyperplasia? what is their phenotype?

A

XX

their phenotype is more male than female

39
Q

which genital ducts/tubules remain in someone with congenital adrenal hyperplasia?

A

BOTH the mullerian and wolffian ducts present

40
Q

what male sex structures are dependent on DHT production?

A

penis, scrotum and prostate

41
Q

a deficiency in 5-alpha-rdeuctase will result in what?

A

a failure of differentiation of the external genitalia

42
Q

what event completes sex differentiation in someone lacking 5-alpha-reductase?

A

increased testosterone production during puberty

43
Q

what causes androgen insensitivity?

A

a loss of functional androgen receptors

44
Q

what is the genotype of someone with androgen insensitivity? what is the phenotype?

A

genotype= XY

phenotype= female

45
Q

t/f: people suffering from androgen insensitivity have no internal genitalia

A

true

they also lack both wolffian and mullerian ducts

46
Q

what is the source for the increased hormone levels during pregnancy?

A

the placenta

47
Q

placental _________ stimulates growth of myometrium

A

estradiol

48
Q

placental __________ reduces uterine contractility and stimulates vasodilation

A

progesterone

49
Q

what hormone supports luteal steriodogenesis?

A

hCG