reproductive endocrinology

Question 1

sex steroids are secreted in significant amounts by the ____, ____, and ____

Answer 1

adrenal cortex; placent; gonads

Question 2

3 major classes of sex steroids differ with respect to the number of ____ they contain

Answer 2

carbons

pregnanes (21), androgens (19), and estrogens (18)

Question 3

testosterone is converted to the most potent androgen, ____, by the enzyme _____

Answer 3

DHT; 5alpha-reductase

Question 4

estradiol is an estrogen produced from ____ by the enzyme ____

Answer 4

testosterone; aromatase

Question 5

the reproductive or ___ axis includes the ____, ____ and _____

Answer 5

HPG; hypothalamus; anterior pituitary gland; gonads

Question 6

activation of steroid receptors regulates gene transcription; in the gonads, the genes transcribed are those regulating ____ and _____

Answer 6

gametogenesis; hormone synthesis

Question 7

3 types of cells in the testes with important reproductive functions

Answer 7

1. spermatic cells (gametes)
2. Leydig cells or interstitial cells
3. Sertoli cells or sustentacular cells

Question 8

spermatic cells (gametes) include ____ and ____

Answer 8

mitotically active spermatogonia; meiotic spermatocytes

Question 9

leydig cells or interstitial cells lie outside the _____; these cells synthesize testosterone in response to ____

Answer 9

seminiferous tubules; LH

Question 10

in the gonad, T regulates ____; in the brain, T regulates ____; elsewhere in the body, T regulates _____

Answer 10

spermatogenesis; sexual behavior (after being aromatized to E2); secondary sex characteristics

Question 11

sertoli cells or sustentacular cells are the ____ cells lining the _____

Answer 11

epithelial; seminiferous tubules

Question 12

in response to ____, sertoli cells regulate _____ and produce the peptide hormone ____

Answer 12

FSH; spermatogenesis; inhibin

Question 13

inhibin has negative feedback actions on ____

Answer 13

FSH secretion

Question 14

sertoli cells also produce an _____ that helps sequester T in the testes so spermatogenesis is continuous; sertoli cells also secrete ____ to provide nutrient support for spermatozoa

Answer 14

androgen binding protein; tubular fluid

Question 15

4 types of cells in the ovary with important reproductive functions

Answer 15

1. oocytes
2. theca cells
3. granulosa cells
4. luteal cells

Question 16

each oocyte is enclosed within a sphere of cells called an _____

Answer 16

ovarian follicle

Question 17

shortly after birth, all oocytes are arrested in _____

Answer 17

prophase of meiosis I

Question 18

theca cells surround each ___; location and function of theca cells is analogous to that of _____

Answer 18

follicle; leydig cells

Question 19

granulosa cells are the ____ cells of the follicle, analogous to ____ cells

Answer 19

epithelial; sertoli

Question 20

luteal cells are present after _____ when the theca and granulosa cells from the ovulatory follicle are transformed into the cells of the _____

Answer 20

ovulation; corpus luteum

Question 21

differentiation of gonadal sex is determined by the presence of a gene on the ___ chromosome that encodes for ____

Answer 21

Y; SRY protein

Question 22

SRY protein directs the indifferent gonad to become a ____

Answer 22

testis

Question 23

the fetal testis produces two hormones that regulate sexual differentiation of the internal genitalia:

Answer 23

testosterone and Mullerian inhibiting substance (MIS)

Question 24

in the undifferentiated state, there are two sets of tubules assoc with the developing gonad:

Answer 24

wolffian ducts and mullerian ducts

Question 25

in a developing male, ____ stimulates proliferation of the ____ that will become the tubules assoc with the male reproductive tract

Answer 25

testosterone; wolffian duct system

Question 26

in the developing male, _____ causes the mullerian duct system to regress

Answer 26

Mullerian inhibiting substance

Question 27

in a developing female, absence of _____ causes regression of the _____

Answer 27

testosterone; wolffian duct system

Question 28

absence of MIS results in proliferation or maintenance of the _____ that becomes the tubules of the female reproductive tract

Answer 28

Mullerian duct system

Question 29

both the male and female external genitalia include ___, ____, and ____ up to about 9 weeks of gestation

Answer 29

genital tubercle; urogenital fold; labioscrotal fold/genital folding

Question 30

fate of genital tubercle, urogenital fold, and labioscrotal folds in the male

Answer 30

genital tubercle –> glans of penis
urogenital fold –> urethra and surrounding penis
labioscrotal folds –> scrotum and skin of penis

Question 31

fate of genital tubercle, urogenital fold, and labioscrotal folds in the female

Answer 31

genital tubercle –> glans of clitoris
urogenital fold –> labia minora and urethral opening
labioscrotal fold –> labia majora

Question 32

spermatogenesis proceeds as the spermatic cells move through the wall of the _____ from the _____ toward the ______ and lumen

Answer 32

seminiferous tubules; basal lamina; apical surface

Question 33

aromatase inhibitors can be used to treat ___ or ____

Answer 33

breast; prostate cancers

Question 34

5a-reductase inhibitors can be used to treat _____ because DHT promotes ____

Answer 34

hair loss; hair loss in male pattern baldness

Question 35

adrenal enzyme deficiency that results in excess production of adrenal androgens

Answer 35

congenital adrenal hyperplasia

Question 36

congenital adrenal hyperplasia can be caused by a mutation in _____ that impairs synthesis of _____

Answer 36

21a-hydroxylase; cortisol

Question 37

development of the ______ is DHT-dependent; enzyme deficiency of _____ results in failure of differentiation of the external genitalia early in life, but increased testosterone secretion with onset of puberty completes differentiation

Answer 37

prostate, penis, and scrotum

5a-hydroxylase

Question 38

with 5a-reductase deficiency, genotype is ____ and phenotype is ____

Answer 38

XY; female at birth until early puberty

Question 39

disease with lack of functional androgen receptor (used by both T and DHT); no differentiation of external genitalia

Answer 39

testicular feminization or androgen insensitivity

Question 40

in testicular feminization, genotype is ____ and phenotype is _____

Answer 40

genotype XY with testes present

phenotype: female (external genitalia and vagina present); no duct system develops

Question 41

placental E2 stimulates:

Answer 41

growth of myometrium

Question 42

placental progesterone reduces ____ and stimulates ____

Answer 42

uterine contractility; vasodilation