Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

brs (phase 1a) > (endo) sex hormones during life > Flashcards

(endo) sex hormones during life Flashcards

1
Q

what is puberty?

A

attaining the capability to reproduce:

  • maturation of reproductive organs + development of secondary sexual characteristics
  • production of sex steroids (e.g. oestradiol, testosterone)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how are adolescents undergoing puberty staged?

A

using Tanner staging from I-V, where I is pre-pubertal and V is adult

1) in girls = thelarche (breast development)
2) in boys = testicular volume
3) both = pubarche (pubic hair)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how is testicular volume determined in males?

A

using a prader orchidometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define gonadarche

A

activation of gonads by HPG axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

define thelarche

A

breast development in females

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

define menarche

A

menstrual cycles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

define spermarche

A

spermatogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

define adrenarche

A

adrenal androgen production

starts approx two year before gonadarche

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

define pubarche

A

pubic hair development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the female secondary sexual characteristics?

A
  • breast development
  • hair growth (pubic, axillary)
  • sweat gland composition (skin oiliness, acne)
  • changes to external genitalia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the male secondary sexual characteristics?

A
  • deepening of voice
  • hair growth (pubic then axillary + facial)
  • sweat gland composition (skin oiliness, acne)
  • changes to external genitalia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

which hormone causes the development of secondary sexual characteristics in males?

A

testosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

which hormone causes the development of secondary sexual characteristics in females?

A

oestradiol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what age does puberty occur in girls?

A

onset = 8-13 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what age does puberty occur in boys?

A

onset = 9-14 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is usually the first sign of puberty in girls?

A

thelarche (e.g. breast development)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the expected testicular size in prepubertal boys?

A

< 4ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the expected testicular size in adult men?

A

> 15ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is GnRH secretion like in childhood?

A

quiescence of HPG axis during childhood

i.e. inactivity, dormancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is GnRH secretion like in puberty?

A

increased nocturnal GnRH pulsatility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is GnRH secretion like in adulthood?

A

normal pulsatile GnRH secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is ‘mini-puberty’ in in males?

A

when GnRH/LH/FSH/oestradiol/T increase in the foetus but falls during infancy to the quiescent phase of childhood

= testicular descent, penile length, Sertoli cell maturation, behavioural effects

(neonatal/foetal activation of the HPG axis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is precocious puberty?

A

when puberty commences before the age of 8

more common in girls > boys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is delayed puberty?

A

when puberty commences after the age of 14

more common in boys > girls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

when does menarche occur?

A

mean age = 12.7 years
(soon after peak height velocity)

approx 2 years after thelarche (breast development)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

define primary amenorrhoea

A

absence of menses at age 15 years in the presence of normal growth and secondary sexual characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

define secondary amenorrhoea

A

when a woman who already menstruates does not get her period for at least 3-6 months

(but common for periods to be anovulatory/irregular for first 18 months)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the commonest physiological cause of secondary amenorrhoea in women?

A

pregnancy (!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

how long is the menstrual cycle on average?

A

approx 28 days

can be 24-35 days, +/- 2 days each month

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

define amenorrhoea

A

1) absence of periods for at least 3-6 months
OR
2) up to 3 periods in total in a year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

define oligomenorrhoea

A

irregular/infrequent periods

1) >35 day cycles
2) 4-9 cycles per year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

differentiate between amenorrhoea and oligomenorrhoea

A

amenorrhoea = absence of periods

oligomenorrhoea = few periods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what happens in the follicular phase of the menstrual cycle?

A

1) increased FSH production
2) stimulates follicular development
3) FSH stimulates the inner granulosa cells of the follicles to start producing E2 and inhibin
4) via negative feedback from E2, FSH levels fall
5) restrict the FSH window and non-dominant follicles, with no FSH, undergo atresia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what does reduced FSH secretion in the follicular phase of the menstrual cycle cause?

A

negative feedback due to increased E2 production
= reduced FSH
= follicular atresia of the non-dominant follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what happens in the pre-ovulatory phase of the menstrual cycle?

A

1) the most E2 secretion happens from the dominant/Graafian follicle
2) the increase in E2 causes a switch to a positive feedback w the gonadotrophins
3) an LH surge results (and to a lesser extent, an FSH surge)
4) the LH surge causes ovulation

36
Q

which hormone is secreted primarily in the luteal phase of the menstrual cycle?

A

progesterone

37
Q

which blood test is done to see if ovulation has taken place?

A

midluteal D21 progesterone

38
Q

which hormone dominates the proliferative phase of the uterine cycle?

A

oestradiol

39
Q

which hormone dominates the secretory phase of the uterine cycle?

A

progesterone

40
Q

what happens in the proliferative phase of he uterine cycle?

A

endometrial lining regrows

41
Q

what happens in the secretory phase of he uterine cycle?

A

transformation of the endometrial lining to be receptive for implantation

42
Q

what is the impact of continuous, non-pulsatile GnRH secretion?

A

decreased LH/FSH secretion

43
Q

what is GnRH pulsatility like during the menstrual cycle?

A

follicular phase = 90-120 mins

luteal phase = 180-240 mins

44
Q

define hypogonadism

A

in men = reduced testosterone

in women = reduced oestrogen

45
Q

what is primary hypogonadism?

A

reduced/no sex steroid production due to damaged gonads

= low E2/T but high LH + FSH

46
Q

what are the possible causes of hypogonadism in men?

A

infection, trauma or cancer of the testes

47
Q

what is the commonest physiological cause of primary hypogonadism in women?

A

menopause

48
Q

what is secondary hypogonadism?

A

reduced/no sex steroid production NOT due to damaged gonads BUT due to a secondary/pituitary cause

= low E2/T and low LH + FSH

49
Q

what are some causes of secondary hypogonadism?

A

high prolactin

pituitary tumour

50
Q

what is secondary hypogonadism also called?

A

hypogonadotrophic hypogonadism

51
Q

what hormone levels are expected in primary hypogonadism in women (e.g. menopause)?

A

low E2/T

high LH + FSH

low inhibin

52
Q

why are inhibin levels low in menopausal women?

A

due to their follicular pool being very small, they have very little inhibin

(this + low E2 causes increased FSH)

53
Q

what are the symptoms of menopause?

A
  • skin dryness
  • hair thinning
  • hot flushes
  • mood disturbance
  • osteoporosis
  • sexual dysfunction
  • weight gain
  • amenorrhoea
  • cessation of fertility
  • climateric periods
54
Q

why is osteoporosis a symptom of menopause?

A

decreased bone mineral density
= as E2 is required to stimulate osteoblast activity

(so in menopause, with little/no E2, osteoblasts cannot function to stimulate bone formation)

55
Q

what are perimenopausal women compared to postmenopausal women?

A

perimenopausal = within 1 year of the last menstrual period (LMP)

postemenopausal = after 1 year of the LMP

56
Q

why is menopause said to be climateric?

A

irregular periods in years close to menopause

57
Q

how is menopause treated?

A

hormone replacement therapy = oestrogen replacement

must also add progeterone! if endometrium is intact

58
Q

why are oestrogen and progesterone both given to treat menopause in women w an endometrium?

A

giving just oestrogen = stimulates the endometrium so MUST ADD PROGESTERONE to prevent the risk of endometrial hyperplasia/cancer

59
Q

when do AMH levels peak in women?

A

in early adult life

60
Q

what is the average age menopause occurs?

A

45-55 years

very few = <1% undergo premature menopause before 40 years

61
Q

what are the symptoms of early menopause?

A

same symptoms as early menopause

62
Q

what is early menopause also known as?

A

premature ovarian insufficiency

conception can still happen in 20% of the cases

63
Q

how is early menopause diagnosed?

A

high FSH (>25 iU/L)

= x2 at least 4 weeks apart

64
Q

what are the main causes of early menopause?

A

autoimmune

genetic (fragile X syndrome, Turner’s syndrome)

cancer therapy

65
Q

how is the total testosterone in circulation found?

A

60% = SHBG-bound testosterone (strongly bound = unavailable)

38% = albumin-bound (weakly bound = bioavailable)

2% = free testosterone (active)

66
Q

what can testosterone in circulation bind to and how does each differ?

A

1) SHBG = strongly bound to this and so is unavailable

2) albumin = weakly bound to this so is bioavailable

67
Q

in late-onset hypogonadism, why does free testosterone fall?

A

usually, SHBG increases w age and so more binds to the free testosterone

= reduces free testosterone levels bc SHBG-bound version is unavailable

68
Q

when is the optimal time to measure testosterone?

A

1) highest in the morning, so should measure it before 11am

2) measure it fasting as presence of glucose can cause T levels to fall by 20%

69
Q

why is testosterone best measured fasting?

A

as presence of glucose can cause testosterone levels to fall by 20%, affecting final results

70
Q

what are the symptoms of testosterone deficiency?

A
  • sexual dysfunction (low libido, erectile dysfunction)
  • low energy levels
  • mood disturbance
  • increased fat + reduced muscle mass
  • gynaecomastia
  • reduced spermatogenesis
  • reduced bone health
71
Q

why do some males with low/borderline testosterone levels have normal sperm production?

A

(testosterone is required for spermatogenesis)

  • testosterone is usually higher in the testes than elsewhere in the blood and so if there are low blood levels of T, the intratesticular levels are usually sufficient enough for spermatogenesis
72
Q

which enzyme catalyses the conversion of testosterone into oestrogen?

A

aromatase

73
Q

which enzyme catalyses the conversion of testosterone into dihydrotestosterone?

A

5-alpha-reductase

74
Q

where is testosterone normally converted into oestrogen?

A
  • ovaries = granulosa cells
  • testes = Sertoli cells
  • brain
  • bone
  • skin
  • adrenal gland
  • adipose tissue
75
Q

where is testosterone normally converted into dihydrotestosterone?

A

testes (seminal vesicle, epididymis)

prostate

liver

76
Q

why is DHT (dihydrotestosterone) produced?

A

more potent ligand for androgen receptor

77
Q

which oestrogen is testosterone converted into?

A

17B-oestradiol

78
Q

which oestrogen is androstenedione converted into?

A

oestrone

79
Q

name an aromatase inhibitor and its use

A

anostrazole

e.g. breast cancer

80
Q

name a 5-alpha-reductase inhibitor and its use

A

finasteride

e.g. prostate cacer

81
Q

what stimulates aromatase action?

A 
age
obesity
insulin
gonadotrophins
alcohol
82
Q

differentiate between primary and secondary hypogonadism

A

primary = problem w the ovaries or testes

secondary = problem w the hypothalamus or pituitary gland

83
Q

why is testosterone important to men?

A

hair growth, sexual function, muscle, voice

84
Q

why is oestrogen important to women?

A

bone health, skin, hair, sexual function

85
Q

why is progesterone important to women?

A

endometrial preparation for implantation

86
Q

what is the male equivalent to POI?

A

POI = premature ovarian insufficiency i.e. menopause before 40

in men = late-onset hypogonadism

brs (phase 1a) (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions