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bioregulatory systems 🦠 > sex hormones > Flashcards

sex hormones Flashcards

1
Q

what is puberty

A

maturation of reproductive organs
production of sex steroids eg oestradiol/testosterone
development of secondary sexual characteristics
attain capability to reproduce

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2
Q

how is puberty graded

A

Tanner staging

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3
Q

in girls, how is puberty graded

A

thelarche - development of the breast

stages 1-5

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4
Q

in boys, how is puberty graded

A

growth of testes
testicular volume
stages 1-5
compared to beads called prader orchidometer

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5
Q

in both boys and girls, how is puberty graded

A

onset of pubic hair
pubarche
stages 1-5

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6
Q

what does gonadarche mean

A

activation of the gonads via HPG axis

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7
Q

what does thelarche mean

A

onset of breast development

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8
Q

what does menarche mean

A

onset of menstrual cycle

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9
Q

what does spermarche mean

A

onset of spermatogenesis

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10
Q

what does adrenarche mean

A

adrenal androgen production (starts ~2 years before gonadarche)

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11
Q

what does pubarche mean

A

onset of pubic hair

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12
Q

what are the 2ndary sexual characteristics in females caused by

A

effects of oestradiol

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13
Q

what are the 2ndary sexual characteristics in females

A

breast development
hair growth - pubarche, axillary
sweat gland composition - skin oiliness, acne
changes to external genitalia

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14
Q

what are the 2ndary sexual characteristics in males caused by

A

effect of testosterone

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15
Q

what are the 2ndary sexual characteristics in males

A

deepening of voice
hair growth - pubic, axillary and facial
sweat gland composition - skin oiliness and acne
changes to external genitalia

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16
Q

what is the 1st sign of puberty in girls

A

thelarche

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17
Q

what is the late sign of puberty in girls

A

menarche

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18
Q

what are the measurements in ml for testicular size for boys at different stages of puberty

A

prepubertal <4mls

adult size > 15mls

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19
Q

what is adrenarche and where does it happen in girls

A

activation of adrenal androgen production

in girls this happens in the ovaries and adrenal glands

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20
Q

where does adrenarche happen in boys

A

in the testes and adrenal gland

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21
Q

Name 2 androgens

A

testosterone and androstenedione

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22
Q

where do some androgens (DHEA/DHEAS) tend to be secreted more from

A

the adrenal glands

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23
Q

in which gender is adrenarche more important for pubarche for

A

girls, as boys have testosterone so they are less reliant on adrenal androgens

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24
Q

what is the first sign of gonadarche

A

activation of the HPG axis - hypothalamic pituitary gonadal axis

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25
Q

what normal secretion is pulsatile

A

GnRH - gonadotrophin releasing hormone

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26
Q

what does GnRH do

A

stimulates the rest of the axis

stimulates gonadotrophs in the pituitary to secrete LH/FSH (gonadotrophins - stimulate growth in testes/ovaries)

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27
Q

what happens to the HPG axis over time

A

in childhood = quiescent
closer to puberty = increased nocturnal GnRH pulsatility and eventually normal pulsatile generation during the day
during late pregnancy and neonatal life there is early activation of the HPG axis

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28
Q

when does menarche start

A

~2-3 years after thelarche
soon after peak height velocity
mean age = 12.7 years (range 10.7-16.1)

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29
Q

what is primary amenorrhoea

A

menarche later than 16 years is regarded as abnormal

30
Q

what is secondary amenorrhoea

A

periods start and then stop for at least 3-6 months

most common physiological cause = pregnancy

31
Q

how long is it common for periods to be irregular/anovulatory for

A

18 months

32
Q

how long is the menstrual cycle in adult women

A

28 day cycle (24-35 days)
+/- 2 days each month
measured from the 1st day of full bleeding

33
Q

what is the definition of amenorrhoea

A

absence of periods
no periods for at least 3-6 months
or up to 3 periods per year

34
Q

what is oligo-menorrhoea

A

few periods
irregular or infrequent periods >35 cycles
4-9 cycles per year

35
Q

what is a follicle

A

in ovaries there are follicles and each follicle is a fluid filled sac containing an egg

36
Q

what do follicles contain

A

granulosa and theca cells which support the development of the egg

37
Q

describe the follicular phase - where FSH rises

A

FSH stimulates follicle to grow
2-3 follicles start to grow
and they produce oestrogen (oestradiol - E2) and hormone inhibin B - both of which negative feedback to hypothalamus and pituitary gland to reduce FSH levels
as FSH decreases, smaller follicles dependent on FSH for growth die - atresia
larger follicles that are less FSH dependent are the dominant follicles
the dominant follicles grow further > E2 produced (at low levels = negative feedback but at high levels = positive feedback - stimulating the hypothalamus and pituitary to make gonadotrophins mostly LH)
mid cycle LH surge - induces ovulation (release of egg from follicle and remainder becomes corpus luteum) which produces progesterone and oestradiol

38
Q

what peaks about 7 days after ovulation

A

progesterone (due to corpus luteum?)

39
Q

what happens at day 21 if levels are too high

A

ovulation

40
Q

describe the uterine cycle

A

as progesterone falls down - induces menstrual bleed
first few days = menstrual bleed
next 10 days = proliferative phase

41
Q

what happens in the proliferative phase

A

(E2 is gradually increasing - important for proliferation of new epithelial cells in endometrium)

  • endometrial lining regrows
  • growth of new epithelial cells
  • gland proliferation
  • increase in stroma/arterioles
42
Q

what happens in the secretory phase

A

progesterone

  • transformation to be receptive for implantation
  • increased volume of stromal cells&raquo_space;> thick spongy lining
  • cork screw shaped glands secreting glycogen
  • coiling and lengthening of spiral arteries
43
Q

what is ovulation

A

release of egg > goes through fallopian tube
where it meets the sperm and becomes fertilised (ampulla region) = embryo
travels to endometrium and implants around day 21

44
Q

if the egg successfully implants in the endometrium, what does it produce and what does it do

A

beta hCG (pregnancy hormone) - stimulates LH receptors as LH surge was important for the corpus luteum > needs LH > maintains functions of the corpus luteum which will survive making progesterone and E2 maintaining the pregnancy

45
Q

what happens if no hCG is produced

A

corpus luteum dies off > no more progesterone made > endometrium sheds > bleeding = new menstrual cycle

46
Q

what happens if GnRH is absent or not pulsatile

A

reduced LH/FSH > reduced ovarian/testicular function

continous non-pulsatile administration of GnRH causes decreased LH/FSH secretion

47
Q

can we measure GnRH

A

no ofc not silly

we use LH as a surrogate marker instead

48
Q

in the follicular phase how often is every LH pulse

A

every 90-120 mins

49
Q

in the luteal phase, how often is every LH pulse

A

slowed by progesterone

every 3-4 hours

50
Q

what is hypogonadism

A

decreased function of the gonads

51
Q

in males, what is hypogonadism

A

testes - decreased testosterone

52
Q

in females what is hypogonadism

A

decreased oestrogen

53
Q

causes of hypogonadism

A

problem with the gonads (testes/ovaries)
problem with hypothalamus/pituitary gland not making enough LH/FSH

  • infections
  • trauma
  • cancer of testes
54
Q

what is primary hypogonadism

A

problem with the gland that is supposed to secrete that hormone (eg testicular or ovarian damage)

55
Q

what happens in hypogonadism

A

normally makes testosterone or oestradiol - negative feedback on hypothalamus and pituitary but now there is reduced negative feedback so more LH/FSH

56
Q

most common cause of hypogonadism in females

A

menopause > ovaries stop functioning > decreased oestrogen > less negative feedback > high FSH/LH

57
Q

which hormone is more related to reducing FSH for menopause

A

inhibin B as inhibin drops because ovaries stop making it > increased FSH

58
Q

what causes secondary hypogonadism

A

decreased function of hypothalamus/pituitary

  • pituitary tumour
  • high prolactin
59
Q

what is hypogonadotropic hypogonadism

A

problem with the gland that controls hormones that stimulates glands that make that hormone

60
Q

symptoms of menopause

A

due to lack of E2 - oestradiol

  • skin dryness/hair thinning
  • hot flushes/sweating/sleep disturbance
  • mood disturbance
  • osteoporosis - decreases bone mineral density (BMD) as E2 stimulates osteoblasts
  • sexual dysfunction - vaginal dryness, low libido
  • weight gain
  • amenorrhoea - perimenopause - within a year of no periods, postmenopause - after 1 year of no periods
  • cessation of fertility
  • climacteric - irregular periods in years closer to menopause
61
Q

treatment for menopause

A

menopause hormone therapy (MHT)

  • oestrogen replacement - oestrogen stimulates the endometrium to proliferate
  • add progesterone - if endometrium is intact to prevent risk of endometrial hyperplasia/cancer
62
Q

what are ovarian reverse markers

A

AMH levels (antimullerian hormone)
peaks at adult
falls off towards menopause
to assess ovarian reserve

63
Q

what cells make AMH

A

granulosa cells in ovaries

64
Q

what age does menopause occur

A

45-55 years

median age 51

65
Q

what age does premature menopause occur

A

<40 years

66
Q

what condition has the same symptoms as menopause and what is its diagnosis

A

early menopause - premature ovarian insufficiency (POI)

high FSH >25 iU/L (2 times at least 4 weeks apart)

67
Q

what are causes of POI

A

autoimmune
genetic - fragile X syndrome/Turners syndrome (XO)
previous cancer therapy - eg. chemo/radiotherapy

68
Q

what is andropause

A

fall of testosterone

peak testosterone = 40 years

69
Q

most of testosterone is..

A

SHBG bound testosterone - stronhly and albumin weakly binds to testosterone
free testosterone 2% is active
late onset hypogonadism

70
Q

what happens to SHBG as you grow older

A

increases with age - produced in liver > less free testosterone
testosterone has diurnal rhythm - highest in the morning - measure before 11am
can fall up to 20% with sugar > measure while fasting ideally

71
Q

testosterone deficiency symptoms

A

sexual dysfunction - low libido
erectile dysfunction - loss of early morning erections
reduced hair growth
reduced energy levels - fatigue
mood disturbance
body composition - increased fat/reduced muscle mass
gynaecomastia - breast enlargement in men
decreased spermatogenesis - high levels of intratesticular testosterone
bone health - via conversion to oestrogen

72
Q

what can testosterone be converted into

A

testosterone > oestrogens by aromatase in adipose tissue
testosterone > dihydrotestosterone by 5 alpha reductase in eg prostate/scalp
DHT is more potent ligand for androgen receptor

bioregulatory systems 🦠 (54 decks)

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