Puberty and its disorders Flashcards

(77 cards)

1
Q

what is puberty

A

transition from non-reproductive to reproductive state and is where secondary sexual characteristics develop

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2
Q

what happens during puberty

A
  • HPGA is activated
  • The adolescent growth spurt
  • Profound physiological changes (hormone increases)
  • Profound psychological changes
  • The gonads produce mature gametes
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3
Q

what are the two major endocrine events of puberty

A
  • adrenarche

- Gonadarche

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4
Q

what is adrenarche

A

Awakening of the adrenal due to maturation of adrenal cortex cells (reticularis), there is secretion of adrenal androgens
-> Results in growth of pubic and axillary hair and the growth spurt

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5
Q

what is gonadarche

A
  • reawakening of HPGA .’. inc LH/FSH
  • inc LH stimulates steroid sythesis .’. secondary sexual characteristics
  • inc FSH .’. growth of testes, steroid synthesis, folliculogenesis
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6
Q

what happens in adrenarche

A
  • increase in adrenal androgen secretion

- androgens secreted from zona reticularis of the adrenal cortex. (newly developed)

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7
Q

what androgens increase in adrenarche

A

DHEA (dehydro-epiandrosterone) and DHEAS (dehydro-epiandrosterone sulfate) only without increased cortisol levels

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8
Q

at what age does adrenarche occur

A

gradual increase in DHEA and DHEAS levels from 6-15 yrs.

peak at 20-25 years.

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9
Q

what is adrenopause

A

the decline in DHEA/DHEAS after its peak

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10
Q

what is pubarche

A

development of pubic hair

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11
Q

why does pubarche occur

A

as a result of adrenarche

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12
Q

why is pubarche associated with ache

A
  • Increased sebum production, often leading to acne

- Infection and abnormal keratinization, also causes acne

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13
Q

what is precocious puberty

A

early puberty

before 8 in girls or 9 in boys

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14
Q

when does gonadarche occur

A

several years after adrenarche (typically around 11 years of age)

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15
Q

what is gonadarche

A

reactivation of the HPG axis, reactivation of hypothalamic GnRH
.’. activated gonadal steroid production
.’. production of viable gametes
.’. ability to reproduce

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16
Q

from which structure is GnRH released

A

hypothalamus. Pulsatile manner

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17
Q

when is HPGA originally activated

A

16th gestational week

pulsatile release occuring in foetus until 1-2 years when it ceases

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18
Q

when is HPGA reactivated

A

11 years in gonadarche

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19
Q

why is LH an indicator of GnRH secretion

A

pulse of GnRH =pulse of LH

.’. LH levels increase in puberty

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20
Q

what stimulates the onset of puberty

A

unclear. could be:
- maturation of GnRH sythesising neurones
- environment/genetics
- Body fat/nutrition
- leptin
- Gut hormone
- kisspeptin

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21
Q

what is the effect of low body fat on ability to reproduce

A

= reduced response to GnRH .’. gonadotrophin .’, amenorrhoea
women lost reproductive ability.
When nourishment occurs or the exercise stops, periods start again.

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22
Q

what % body fat is required for menarche and to maintain female reproduction

A

menarche - 17%

maintain female reproductive ability - 22%

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23
Q

what is kisspeptin

A

a neurohormone.

directly regulates GnRH secretion

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24
Q

where does kisspeptin exert is action and what does it do

A

receptors are on dendrites of GnRH neurones and so directly regulates GnRH secretion.

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25
mutations in GPR54 (kisspeptin receptor) or the gene coding for kisspeptin results in:
- abnormal development of GnRH neurones -> hypogonadism - failure to enter puberty - hypothalamic hypogonadism - Activating mutations of kisspeptin receptor -> precocious puberty
26
what is meant by consonance of puberty
all changes that occur in puberty occur in the same order (just at different ages)
27
what is the first change of puberty in females
breast bud formation
28
what is the first change of puberty in males
testicular volume increases to above 4ml
29
how many tanner stages of puberty are there
5 first being hasnt entered puberty last being puberty is complete
30
how does the first tanner stage of puberty present
(females) no breast tissue (males) prepubertal genital development (both) no pubic hair
31
how does the second tanner stage of puberty present
``` (females) areolar enlargement breast bud (males) testis enlarged to 4ml. scrotum larger. skin coarser. (both) no pubic hair ```
32
how does the third tanner stage of puberty present
(females) enlargement of breast and areolar as a single mould (males) penis enlarged in length. continued growth of penis and scrotum (both) curly pigmented hairs across pubes
33
how does the fourth tanner stage of puberty present
(females) projection of areola above breast (males) growth of penis in length and diameter. pigmentation of scrotum (both) small adult configuration of hair
34
how does the fifth tanner stage of puberty present
puberty complete (females) papilla projects out of areola forming part of breast contour) (males) testis, scrotum and penis at adult size (both) hair in adult configuration with spread onto thighs
35
what is the first outward sign of estradiol activity in females
breasts enlarge
36
physical changes in females at puberty
- breasts enlarge - growth of pubic/axillary hair - uterus enlarges - cytology changes in uterus and secretions - height increase - changes in body shape (widened hips)
37
how does pubertal height increases differ in boys and girls
Growth spurt occurs earlier in girls than in boys
38
physical changes in males at puberty
- growth of external genitalia - vans deferens lumen diameter increases - Growth of facial/body hair - Growth of pubic/axillary hair - larynx enlargement - height increase - fertility
39
how does male external genitalia change at puberty
increase in testicular volume to above 4ml | growth of penis, scrotum and scrotal skin changes
40
how does the male larynx change at puberty
- androgens = enlargement of larynx - development of adams apple (a projection of the thyroid cartilage) - voice deepens
41
at what age is the peak height growth in males and females
females - 12yrs | males - 14yrs
42
how does fertility change at puberty for males
Testosterone from Leydig cells stimulates meiosis and spermatogenesis in Sertoli cells
43
what hormones cause the growth spurt (males and females)
complex interaction between growth hormone and oestrogen
44
effect of oestrogens on epiphyseal growth
biphasic effect 1 - early puberty has low levels of oestrogens -> support linear bone growth and bone maturation 2 - later puberty has high levels of oestrogen -> epiphyseal fusion = bone fusion and decrease in growth spurt
45
what are Pilosebaceous Units (PSUs)
The structure consisting of hair, hair follicle, arrector pili muscles, and sebaceous gland is an epidermal invagination
46
how do androgens affect differentiation of pilosebaceous Units (PSUs)
Androgens will cause Vellus PSU to differentiate into - Terminal PSUs that form the beard and moustache - APO-PSUs which form the pubic and axillary hair
47
what is vellus hair
Vellus hair is short, thin, slight-colored, and barely noticeable thin hair that develops on most of a person's body during childhood.
48
what are the psychological changes of puberty
1. Increasing need for independence 2. Increasing sexual awareness/interest 3. Development of sexual personality
49
what is precocious sexual development
pubertal changes occur early (before 8 in girls and 9 in boys) but in consonance
50
what are the two types of precocious puberty
1 - Gonadotrophin-dependent (central) precocious puberty | 2 - Gonadotrophin-independent precocious sexual development
51
what is Gonadotrophin-independent precocious sexual development
early sexual development where there is a loss of consonance
52
what is Gonadotrophin-dependent (central) precocious puberty
early sexual development in consonance due to reawakening of HPGA
53
what may cause Gonadotrophin-dependent (central) precocious puberty
- excess GnRH secretion (idiopathic or secondary | - excess gonadotrophin from a pituitary tumour
54
what may cause Gonadotrophin-independent precocious sexual development
- testotoxicosis - McCune Albright Syndrome - A sex steroid secreting tumour - exogenous steroids
55
what is testotoxicosis
is a type of gonadotropin-independent precocious development | - activating mutation of LH receptor, causing early virilsation of external genitalia
56
what is McCune Albright Syndrome
-adenylyl cyclase and cAMP constantly active | = café au lait skin pigmentation + other endocrine disorders such as fibrous dysplasia
57
what is pseudo precocious puberty
partial pubertal development that results from autonomous (gonadotropin-independent) production of estrogen in prepubertal girls.
58
what may cause pseudoprecocious puberty
- Premature adrenarche/pubearche | - result of CAH or Cushing's
59
how may we investigate precocious sexual development
- auxology - pubertal staging analysis - estimate bone age - LH, FSH and sex steroid measurements - testing LH response to 100micrograms of GnRH - Measure adrenal steroids - MRI of hypothalamic-pituitary area - Ultrasound scans of pelvis
60
what is auxology
accurate measurement of height, body proportions, weight and how they all come together
61
what is pubertal staging analysis
find which stage individual is at in puberty, tanner scale or orchidometer may be used here
62
what can we use to measure bone age
DEXA scan
63
why may we measure LH, FSH and sex steroid in precocious puberty
tell us if the HPG axis has been re-awakened or there is an isolated increase in one of them
64
why may we test LH response to GnRH in precocious puberty
- peak in LH in response would be indicative of central precocious puberty - LH suppressed in testotoxicosis
65
why may we do an ultrasound of pelvis in response to precocious puberty
see their maturation and thickness of uterus giving an indication of levels of oestrogen.
66
how may we treat precocious puberty
- Anti-androgens for premature adrenarche - 5a-reductase inhibitor to stop virilisation of external genitalia (eg in testotoxicosis) - Aromatase inhibitor; inhibit oestrodiol + oestrogen production - long-acting GnRH analogue in central precocious puberty to down-regulate HPG axis
67
what may be treatment for premature adrenarche
antiandrogens
68
what may be treatment for virilisation of external genitalia (eg in testotoxicosis
5a reductase inhibitor
69
what may be used as a treatment for central precocious puberty
long acting GnRH | to downregulate HPGA
70
what is meant by pubertal delay
absence of secondary sexual maturation (characteristics) by 13yrs in girls (or absence of menarche by 18yrs) or 14yrs in boys
71
reasons for pubertal delay
- constitutional delay - hypogonadotrophin hypogonadism (low LH&FSH) - Hypergonadotrophin hypogonadism (high LH and FSH)
72
why may Constitutional delay = pubertal delay
Affects both growth and puberty - where reactivation of HPG axis doesn't occur - could be idiopathoc or secondary to a chronic disease
73
what may Hypogonadotrophin hypogonadism = pubertal delay
this is low levels of gonadotrophin hormones, may be a result of a genetic mutation
74
why may Hypergonadotrophin hypogonadism = pubertal delay
= high LH/FSH normal higher functioning of hypothalamus and pituitary problem lies at gonads = low sex steroid levels
75
how does turners syndrome (45X0) present
- Being shorter than normal | - Having underdeveloped or 'streak' ovaries
76
how may we investigate delayed puberty
- Start of by looking at family history, any dysmorphic features, anosmia - auxology - pubertal staging - bone age estimation - LH. FSH, Sex steroid measurements - LH response to 100micrograms of GnRH - MRI scans of hypothalamo-pituitary area - ultrasound of pelvis, tell us about oestrogenic activity
77
how may we treat delayed puberty
- Give testosterone in males - Give oestrogens in females to cause breast development, growth spurt etc. - Give oxandralone (a synthetic steroid) - wait for puberty to start