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endocrine term 2 quiz 1 - julia's notes > chapter 10 > Flashcards

chapter 10 Flashcards

1
Q

ways to characterize gender

A

1: genetic sex (XX or XY)
2: gonadal sex (testes or ovaries)
3: phenotypic or genital sex

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2
Q

genetic sex development

A

testes develop in genetic males at gestational weeks 6 to 7

ovaries at gestational week 9 in females

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3
Q

differences between male and female gonads

A

1: testes synthesize antimullerian hormone, ovaries don’t
2: testes synthesize testosterone, ovaries don’t

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4
Q

male phenotype

A

internal genital tract that includes prostate, seminal vesicles, vas deferens, and epididymis
external genitalia that includes scrotum and penis
testes secrete antimullerian hormone and testosterone - required for male phenotype

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5
Q

female phenotype

A

internal genitalia that includes Fallopian tubes, uterus, upper one-third of vagina
external genitalia that includes clitoris, labia majora, labia minora, and lower 2/3 of the vagina
ovaries secrete estrogen

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6
Q

development of male phenotype

A

wolffian ducts give rise to epididymus, vas deferens, seminal vesicles, and ejaculatory ducts
testosterone stimulates growth and differentiation of wolffian ducts - act ipsilaterally
AMH from testicular sertoli cells causes atrophy of Müllerian ducts
external genitalia at 9-10 weeks - growth depends on conversion of testosterone to dehydrotestonsterone and the presence of receptors in target tissue

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7
Q

development of female phenotype

A

no testosterone to stimulate growth and differentiation of wolffian ducts
no AMH to suppress development of Müllerian ducts, so ducts develop into Fallopian tubes, uterus, and upper 1/3 of vagina
development of external also doesn’t require hormones but growth to normal size requires estrogen

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8
Q

GnRH

A

begins at week 4 but levels remain low until puberty - increases and becomes pulsatile
initiation of puberty due to pulsatile secretion - drives parallel pulsatile secretion of FSH and LH
also increased sensitivity to GnRH in anterior pituitary

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9
Q

FSH

A

secretion begins between weeks 10 and 12 - low until puberty when increases and becomes pulsile - higher than LH levels until puberty- stimulates secretion of gonadal steroid hormones

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10
Q

LH

A

secretion begins between weeks 10 and 12 - low until puberty when increases and becomes pulsile - lower than LSH until after puberty - results in secretion of gonadal steroid hormones

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11
Q

testosterone

A

synthesized and secreted by leydig cells
note: testes don’t have 21-beta hydroxyalse or 11-beta hydroxylase so can’t make glucorticoids or mineralocorticoids
have 17-beta hydroxysteroid dehydrogenase that converts androstenedione to testosterone (so get testosterone rather than DHEA and androstenedione)

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12
Q

steps in synthesis of testosterone

A

1: cholesterol desmolase converts cholesterol to pregnenolone - activated by LH
2: 17-alpha hydroxylase converts pregnenolone to 17-hydroxypregnenolone
3: 17,20 lyase converts 17-hydroxypregnenolone to dehydroepiandrosterone
4: 3-beta-hydroxysteroid dehydrogenase converts dehydroepiandrosterone to androstenedione
5: 17beta hydroxysteroid dehydrogenase converts androstenedione to testosterone
6: in target tissues, 5alpha reductase converts testosterone to dihydrotestonsterone

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13
Q

17beta hydroxysteroid hydrogenase

A

only in testes

converts androstenedione to testosterone

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14
Q

5alpha reductase

A

enzyme in target tissues of testosterone that converts testosterone to dihydrotestosterone

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15
Q

sex steroid binding globulin

A

binds circulating testosterone/sex hormones

only free testosterone active so functions as reservoir

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16
Q

regulation of testosterone production

A

hypothalamus releases GnRH
GnRH activates release of FSH and LH from anterior pituitary
FSH acts on Sertoli cells - stimulates spermatogenesis
LH acts on leydig cells - increases activity of cholesterol desmolase
leydig cells make testosterone
testosterone activates Sertoli cells (paracrine transmission) - reinforces spermatogenic action of FSH and induces release of inhibin
inhibin inhibits FSH production in ant. pituitary
testosterone inhibits both hypothalamus and anterior pituitary - inhibits secretion of GnRH and LH - in hypo, decreases frequency and amplitude of GnRH pulses

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17
Q

actions mediated by testosterone

A 
differentiation of epididymus, vas deferens, and seminal vesicles
increased muscle mass
pubertal growth spurt
cessation of pubertal growth spurt, epiphyseal closure
growth of penis and seminal vesicles
deepening of voice
spermatogenesis
negative feedback on anterior pituitary
libido
18
Q

actions mediated by dihydrotestosterone

A 
differentiation of penis, scrotum, and prostate
male hair pattern
male pattern baldness
sebaceous gland activity
growth of prostate
19
Q

development of ovarian follicles

A

stage 1: prophase of oocyte, granulosa cells proliferate and nurture oocyte with nutrients and steroid hormones, develops into primary follicle, theca interna cells develop, granulosa cells begin to secrete fluid
stage 2: fluid containing steroid hormones, mucopolysaccharides, proteins, and FSH accumulates in antrum of follicle - steroid hormones secreted by granulosa cells
granulosa and theca cells continue to grow
now Graafian follicle
stage 3: single graafan follicle achieves dominance over cohorts and cohorts regress, dominant follicle grows, ruptures, releases oocyte
residual elements form corpus luteum - mostlly granuloa cells - synthesizes and secretes steroid hormones - regress if fertilization does not occur

20
Q

ovarian steroid hormones

A

progesterone and 17beta estardiol

synthesized by ovarian folliles through combined function of the granulosa cells and theca cells

21
Q

steps in synthesis of ovarian hormones

A

1: cholesterol desmolase from theca cells converts cholesterol to pregnenolone - stimulated by LH
2a: 3-beta-hydroxysteroid dehydrogenase converts pregnenolone to progesterone (secreted by theca cells)
2b: 17-alpha hydroxylase converts pregnenolone to 17-hydroxypregnenolone
3b: 17,20 lyase converts 17-hydroxypregnenolone to dehydroepiandrosterone
4b: 3-beta hdyroxysteroid dehydrogenase converts dehydroepiandrosterone to androstenedione (secreted and goes to granulosa cells)
5b: 17-beta hydroxysteroid dehydrogenase (from granulosa cells) converts androstenedione to testosterone
6b: aromatase (from granulosa cells) converts testosterone to 17-beta estradiol - activated by FSH

22
Q

aromatase

A

enzyme only in ovary
converts testosterone to 17beta estradiol
activated by FSH

23
Q

FSH in menstrual cycle

A

only granulosa cells have receptors
initially stimulates growth of granulosa cells in primary follicles
stimulates estradiol synthesis
estradiol then supports trophic effect of FSH on follicular cells

24
Q

LH in menstrual cycle

A

initiates ovulation
blood concentration rises sharply - induces rupture of dominant follicle
stimulates formation of corpus luteum (luteninization)
maintains steroid hormone production by corpus luteum during luteal phase

25
Q

control of female hormones during follicular phase

A

hypothalamus makes GnRH
activates release of FSH and LH from anterior pituitary
FSH and LH act on ovary
ovary releases estradiol
estardiol INHIBITS FSH and LH release in anterior pituitary

26
Q

control of female hormones during midcycle

A

hypothalamus makes GnRH
activates release of FSH and LH from anterior pituitary
FSH and LH act on ovary
estradiol levels rise sharply because of proliferation of follicular cells and stimulation of estradiol synthesis during follicular phase
critical level of estradiol upregulates GnRH receptors in anterior pituitary
ACTIVATES FSH and LH release in anterior pituitary
results in ovulatory surge of FSH and LH - ovulation

27
Q

luteal phase

A

hypothalamus makes GnRH
activates release of FSH and LH from anterior pituitary
FSH and LH act on ovary
ovary releases progesterone
progesterone inhibits FSH and LH release in anterior pituitary

28
Q

actions of estrogen

A

maturation, maintenance of uterus, Fallopian tubes, cervix and vagina
responsibilty at puberty for the development of female secondary sex characteristics
requisite for development of breasts
responsibility for proliferation and development of ovarian granulosa cells
upregulation of estrogen, progesterone, and LH receptors
negative AND positive feedback effects on FSH and LH secretion
maintenance of pregnancy
lowering of uterine threshold to contractile stimuli
decreasing LDL cholesterol
blocking action of prolactin in breast
anti-osteoporosis

29
Q

actions of progesterone

A

maintenance of secretory activity of uterus during luteal phase
development of breasts
negative feedback effects on FSH and LH
maintenance of pregnancy
raising uterine threshold to contractile stimuli during pregnancy

30
Q

hormonal control of uterus

A

estrogen causes cell proliferation, cell growth, and increased contractility

progesterone increases secretory activity and decreases contractility - during secretory phase causes proliferation of endometrium to slow and thickness to decrease, uterine glands become tortuous, accumulate glycogen in vacuoles, increase mucus secretions, spiral arteries elongate more and become coiled, decreases quantity of cervical mucus, becomes thick

estradiol stimulates growth of endometrium, growth of glands and stroma, and elongation of spiral arteries during proliferative phase, causes cervical mucous to become copious, watery and elastic

31
Q

hormonal control of Fallopian tubes

A

estrogen stimulates ciliary activity - aids in movement of sperm to uterus
progesterone increases secretory activity, decreases contractility

32
Q

hormonal control of vagina

A

estrogen stimulates proliferation of epithelial cells

progesterone stimulates differentiation but inhibits proliferation of epithelial cells

33
Q

hormonal control during pregnancy

A

estrogen stimulates growth of myometrium, growth of ductal system of breasts, prolactin secretion, and enlargement of external genitalia
progesterone maintains endometrial lining of uterus, increases uterine threshold to contractile stimuli - preserves pregnancy until fetus ready to be delivered

34
Q

non-sex actions of estrogen

A

contributes to pubertal growth spurt
closure of epiphyses
deposition of subcutaneous fat

35
Q

non-sex actions of progesterone

A

mild thermogenic action - increases basal body temperature during luteal phase of menstrual cycle

36
Q

follicular or proliferative phase

A

1st phase of menstrual cycle
day 0 to day 14
primordial follicle develops into Graafian follicle, neighboring follicles become atretic
receptors for FSH and LH are upregualted in ovarian theca
levels of estradiol increase, cause proliferation of endometrial lining of uterus, inhibit FSH and LH secretion by anterior pit.

37
Q

ovulation phase

A

on day 14 - always 14 days prior to menses
burst of estradiol secrtion at end of follicular phase has postive feedback effect on FSH and LH = FSH and LH surge
ovulation occurs
crevical mucus increases in quantity and becomes watery and more penetrable by sperm
estradiol levels decrease just after

38
Q

luteal or secretory phase

A

third phase of menstrual cycle
from ovulation until menses
corpus luteum develops and begins synthesizing estradiol and progesterone
high levels of progesterone stimulate secretory activity of endometrium and increase its vascularity - preparing it to receive fertilized ovum
basal body temperature increases
cervical mucus less abundant and thicker
if fertilization has not occurred, corpus luteum regresses, sources of estradiol and progesterone lost

39
Q

menses

A

when corpus luteum regenerates estradiol and progesterone abruptly lost
endometrial lining and blood sloughed
during this time, primordial follicles for next cycle being recruited and beginning to develop

40
Q

implantation

A

highest levels of progesterone

when implantation occurs endometrium differentiates into decidual cells

41
Q

human chorionic gonadotropin (HCG)

A

trophoblast begins secreting about 8 days after ovulation
activity similar to LH
informs corpus luteum that fertilization has occured - tells it to continue to synthesize progesterone and estrogen

endocrine term 2 quiz 1 - julia's notes (2 decks)

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