puberty Flashcards
what does puberty describe
the physiological, morphological, and behavioural changes as the gonads switch from infantile to
adult forms
what is the definitive sign of puberty onset in girls
Girls – menarche – first menstrual bleeding
what is the definitive sign of puberty onset in boys
boys – first ejaculation – often nocturnal
do the first definitive signs of puberty signify fertility
no
when do secondary sexual characteristics occur
at puberty
what are the secondary sexual characteristics for girls
Ovarian oestrogens regulate the growth of breast and female genitalia
Ovarian and adrenal androgens control pubic and axillary hair
what are the secondary sexual characteristics for boys
Testicular androgens – external genitalia and pubic hair growth, enlargement of larynx and laryngeal muscles (voice deepening)
what is the tanner scale
A scale that defines physical measurements of development based on external primary and secondary sex characteristics.
stage 1 of tanner scale - boys
- Prepubertal: No pubic hair
- Testicular length <2.5 cm
- Testicular volume <3.0 mL
stage 2 of tanner scale - boys
- Sparse growth of slightly curly pubic hair, mainly base of penis
- Testes > 3 mL (>2.5 cm in longest diameter)
- Scrotum thinning and reddening
stage 3 of tanner scale - boys
- Thicker, curlier hair spread to mons pubis
- Growth of penis in width and length; further growth of testes
stage 4 of tanner scale - boys
- Adult-type hair, not yet spread to medial surface of thighs
- Penis further enlarged; testes larger, darker scrotal skin colour
stage 5 of tanner scale - boys
- Adult-type hair spread to medial surface of thighs
- Genitalia adult size and shape
what does an orchidometer measure
testicular volume in ml
stage 1 of tanner scale - girls
- Prepubertal: No pubic hair
- Elevation of papilla onl
stage 2 of tanner scale - girls
- Sparse growth of long, straight or slightly curly, minimally pigmented hair, mainly on labia
- Breast bud noted/ palpable; enlargement of areola
stage 3 of tanner scale - girls
*Darker, coarser hair spreading over mons pubis
* Further enlargement of breast and areola, with no separation of contours
stage 4 of tanner scale - girls
- Thick adult-type hair, not yet spread to medial surface of thighs
- Projection of areola and papilla to form secondary mound above level of breast
stage 5 of tanner scale - girls
- Hair adult-type and distributed in classic inverse triangle
- Adult contour breast with projection of papilla only
what is the first visible change of puberty for girls
Thelarche – breast development
what induces breast develpment
oestrogen
how long does breast development take
about 3 years
3 effects of oestrogen on breast
- Ductal proliferation
- Site specific adipose deposition
- Enlargement of the areola and nipple
can breasts be unilateral
yes for several months
Other hormones involved in breast development
prolactin, glucocorticoids, insulin
describe pre pubertal uterus
- Corpus : cervix ratio 1:2
- Tubular shape
- Length 2-3 cm
- Volume 0.4-1.6 ml
- Endometrium single layer of
cuboidal cells
describe pubertal - adult uters
- Corpus : cervix ratio 2:1
- Pear shape
- Length 5-8 cm
- Volume 3-15 ml
- Endometrium increased
thickness
describe pre pubertal ovaries
- Volume 0.2-1.6 ml
- Non functional
describe pubertal - adult ovaries
- Volume 2.8-15 ml
- Multicystic
what to check in a pevlic ultrasound - females
- Are the Mullerian structures present?
- Morphology of uterus?
- Morphology of ovaries?
describe pre pubertal vagina
- Reddish in colour
- Thin atrophic columnar epithelium
- pH neutral
*Length 2.5-3.5 cm
describe pubertal - adult vagin
- Dulling of the reddish colour
- Thickening of the epithelium
- Cornification of the superficial layer stratified squamous epithelium
- pH acidic 3.8-4.2
- Secretion of clear whitish
dischargein the months
before menarche - Length 5-8 (-12)cm
what happens under the effect of oestrogens
– Labia majora & minora increase in size & thickness
– Rugation & change in colour of the labia majora
– Hymen thickens
– Clitoris enlarge
– Vestibular glands begin secretion
what do Adrenal androgens & ovarian androgens cause
growth of pubic and axillary hair
define precocious puberty
onset of secondary sexual characteristics before 8 years (girls), 9 years (boys)
what can Menarche before 9 yrs cause
may lead to short stature
define delayed puberty
absence of secondary sexual characteristics by 14 years (girls), 16 years (boy)
what can delayed puberty lead to
reduced peak bone mass and osteoporosis
describe female HPG axis
hyppthalamus -> GnRH
anterior pituitary -> LH & FSH
FSH -> bind to granulosa cells -> convert androgens to oestrogen
LH -> act on theca cells -> produce andorgens
describe male HPG axis
hyppthalamus -> GnRH
anterior pituitary -> LH & FSH
LH -> stimulate leydig cells to make testeosterone
FSH -> stimulates sertoli cells to make ABG & inhibin
what are physical change aat puberty controlled by
by gonadal and adrenal sex steroids regulated by the
gonadotrophins, LH and FSH
what is the Hypothalamic maturation hypothesis
(GnRH pulse generator)
– Puberty only requires increased hypothalamic GnRH
– Emphasises the direct link 1CNS and pituitary and hypothalamic GnRH neurons
at the start if puberty what factors regulate GnRH secretion (INCREASED STIMULATORY FACTORS)
glutamate and kisspeptin
at the start if puberty what factors regulate GnRH secretion (DECREASED INHIBITORY FACTORS)
mostly through GABAergic neurons secreting γ-aminobutyric
acid (GABA) and opioidergic neurons
what is adrenarche
Maturational process of the adrenal gland
which species is adrenarche observed in
Only observed in humans and in some old world primates
impacts of adrenarche
Mild advanced bone age, axillary hair, oily skin, mild acne, body odour
what is pubarche
Most pronounced clinical result of adrenarche
Result of androgen action on the pilosebaceous unit transforming vellus hair into terminal hair in hair-growth prone parts of the skin
treatment of precocious puberty
GnRH superagonist to suppress pulsatility of GnRH secretion
what % of children have delayed puberty
3%
is delayed puberty more common in girls or boys
boys
what can delay in puberty lead to
delay in acquisition
of secondary sex characteristics, psychological problems, defects in reproduction and reduced peak bone mass
Indications for investigation of delayed puberty - girls
- Lack of breast development by 13 yrs
- More than five years between breast development and menarche
- Lack of pubic hair by age 14 yrs
- Absent menarche by age
15-16 yrs
Indications for investigation of delayed puberty - boys
- Lack of testicular enlargement by age 14 yrs
- Lack of pubic hair by age 15 yrs
- More than 5 years to complete genital enlargement
diseases associated with delayed puberty
Idiopathic (constitutional) delay in growth and puberty
Hypogonadotrophic hypogonadism
Hypergonadotrophic hypogonadism
what is Idiopathic (constitutional) delay in growth and puberty
– delayed activation of the hypothalamic pulse
generator
what is Hypogonadotrophic hypogonadism
sexual infantilism related to to gonadotrophin
deficiency
lab investigations for delayed puberty
- Complete red blood count
- U + E, renal, LFT
- LH, FSH
- Testosterone/ oestradiol
- Thyroid function, prolactin
what test to do in all girls with short stature
karyotyping
Physical examination/ biochemistry suggestive of
genetic syndrome
functional cuases for delayed puberty
Chronic renal disease
Chronic lung disease
Anorexia nervosa
Psychosocial/ stress
Drugs
what is hypogonadism
Reduction or absence of hormone secretion of the gonads.
what happens to ovary in female hypogonadism
Oestrogen goes down
Lack of feedback
LH and FSH increase
what happens to hypothaalmys and pituitary in hypogonadism
LH and FSH low
No response to feedback
Oestrogen decreases
what happens to testes in male hypogonadims
Testosterone goes down
Lack of feedback
LH and FSH increase
what happens to hypothalamus and pituitary in hypogonadism
LH and FSH low
No response to feedback
Testosterone decreases
what is primary hopogonadsm
ovary or testes fails
what is secondary hypogonadims
hypothalamus or pituitary fails
describe tuner syndrome
Turner syndrome – 45, X0 girls
Renal malformations – horseshoe kidney (fusion of the kidney)
Short stature
Cardiovascular malformations – aortic arch, spontaneous rupture
1 in 2000 girls
