reproductive endocrinology

Question 1

testosterone (the primary male sex hormone) is an __________

Answer 1

androgen

Question 2

_________ is more potent than DHEA or androstenedione

Answer 2

testonsterone

Question 3

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

Answer 3

1) estradiol- an estrogen

2) progesterone- a progestin

Question 4

how is estradiol produced?

Answer 4

from testosterone by AROMATASE

Question 5

when is progesterone the primary female sex steroid?

Answer 5

during part of the menstrual cycle and during pregnancy

Question 6

the secretion of GnRH is _________

Answer 6

pulsatile- due to control by neuroendocrine system

Question 7

continuous, nonpulsatile GnRH will inhibit _____ and _____ secretion

Answer 7

FSH and LH secretion

Question 8

gonadal hormones have negative feedback actions on both _______ and ________

Answer 8

GnRH and LH/FSH

Question 9

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

Answer 9

ovulation

Question 10

the positive feedback action of ______ controls ovulation in females

Answer 10

estrogen

Question 11

what cells synthesize testosterone in response to LH in males?

Answer 11

leydig cells

Question 12

__________ cells line the seminiferous tubules

Answer 12

sertoli cells

Question 13

what are the functions of the sertoli cells?

Answer 13

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

Question 14

testosterone has a negative feedback action on _____ and ______

Answer 14

GnRH and LH

Question 15

what does inhibin reduce?

Answer 15

production of FSH

Question 16

what enzyme converts testosterone to DHT?

Answer 16

5-alpha-reductase

Question 17

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

Answer 17

DHT (dihydrotestosterone)

Question 18

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

Answer 18

arrested in meiosis 1

enclosed in a follicle

Question 19

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

Answer 19

theca cells

Question 20

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

Answer 20

aromatize androstenedione (androgens) into estradiol in response to FSH

also produce inhibin

Question 21

the theca cells synthesize ___________ in response to LH

Answer 21

androstenedione

Question 22

granulosa cells convert the androstenedione into ______

Answer 22

estradiol

Question 23

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

Answer 23

estradiol

Question 24

what are the 2 phases of the ovarian cycle?

Answer 24

folicular and luteal

Question 25

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

Answer 25

estrogen

Question 26

when does the ovarian cycle begin?

Answer 26

begins with menstrual flow when CL regresses

Question 27

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

Answer 27

true

Question 28

the corpus luteum will regress when _____________ levels are too low

Answer 28

gonadotropins

Question 29

if pregnancy occurs, the placenta will produce what hormone?

Answer 29

human chorionic gonadotropin (hCG)

Question 30

what is the function of hCG?

Answer 30

maintains luteal steroidogenesis until the placenta fully develops

Question 31

after menopause, the body must rely on _________ androgens

Answer 31

adrenal

Question 32

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

Answer 32

LH and FSH are very high

there is no negative feedback placed on them anymore

Question 33

the physiological consequences of menopause are mostly due to what?

Answer 33

decreased estrogens

Question 34

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

Answer 34

mullerian and wolffian ducts

men- wolffian ducts remain
women- mullerian ducts remain

Question 35

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

Answer 35

testosterone (stimulated proliferation of wolffian ducts)

mullerian inhibiting substance

Question 36

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

Answer 36

testosterone

Question 37

what causes congenital adrenal hyperplasia?

Answer 37

results from a mutation in steroidogenic enzymes

Question 38

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

Answer 38

XX

their phenotype is more male than female

Question 39

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

Answer 39

BOTH the mullerian and wolffian ducts present

Question 40

what male sex structures are dependent on DHT production?

Answer 40

penis, scrotum and prostate

Question 41

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

Answer 41

a failure of differentiation of the external genitalia

Question 42

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

Answer 42

increased testosterone production during puberty

Question 43

what causes androgen insensitivity?

Answer 43

a loss of functional androgen receptors

Question 44

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

Answer 44

genotype= XY

phenotype= female

Question 45

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

Answer 45

true

they also lack both wolffian and mullerian ducts

Question 46

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

Answer 46

the placenta

Question 47

placental _________ stimulates growth of myometrium

Answer 47

estradiol

Question 48

placental __________ reduces uterine contractility and stimulates vasodilation

Answer 48

progesterone

Question 49

what hormone supports luteal steriodogenesis?

Answer 49

hCG