REPRO - Puberty Flashcards
What is adrenarche instigated by?
What does it result in?
- by awakening of adrenal viaz.reticuarlis cx maturation
- androgen secretion –> pubarche (hair) due to DHEA/DHEAS (dehydroepiandosterone)
What is Gonadarche the re-awakening of? What are the results of increased LH/FSH?
- HPG axis, LH causes steroid synthesis in gonads
- FSH causes this + growth of testis/folliculogenesis
When is Adrenarche?
From about 10yrs increases, peaks mid 20s then declines “adrenopause”
What are DHEAS in the circulation converted to at target tissues?
Testosterone/DHT
When is pubarche said to be precocious?
Girls=before 8yrs
Boys=before 9yrs
What is pubarche associated with?
- increased sebum production, acne, infection, abnormal keratinisation
- pilosebaceous units (PSUs) deposit sebum on the hairs
When is the HPG axis first activated? Until when? Then GnRH neurones are ‘restrained’ until…
- 16wk gestation to 1 or 2yrs postnatally
- about 10yrs old, pulsatile GnRH in gonadarche reactivates it
In terms of bones, the initial low levels of oestrogen as the HPG A. reawakens promotes..
..linear growth and causes the initial rapid growth spurt (2yrs earlier in girls)
As oestrogen levels are higher you get…
epiphyseal fusion and growth stops
What is consonance?
a smooth ordered progression of changes regardless of length
Name 5 male physical changes in puberty..
- ext genitalia: 4ml testicular vol, scrotal growth and skin change. Vas def. lumen increases
- seminal vesicles and prostate - mature
- larynx: enlarges, thyroid cartilage protudes, voice deepens
- height 10cm/yr reached 14yrs
- Shoulders and chest broaden > hip
Name 5 female physical changes in puberty..
- Thelarche (1st sign of E2 hence HPG reawakening)
- Hips widen
- Height 9cm/yr reached at 12yrs
- Uterus enlarges, myometrium responds to E2
- Endometrium, tubes, cervix mature
- Menarche late in puberty
Fertility differences by sex:
Male = immediate fertility. Testosterone stimulates meiosis and spermatogenesis in Sertoli cells Female = later, first yr of menarche 80% cycles are anovulatory/irregular
3 psychological changes in puberty are:
- need for independence
- more sexual awareness
- sexual personality develops
Central Precocious puberty is gonadotrophin dependent. Consonance is maintained. Causes?
- excess GnRH idiopathic or secondary
- secondary may be from a pituitary tumour
Central Precocious Puberty signs..
- accelerated linear growth
- advanced bone age
- increased FSH/LH/E2/testosterone
Central Precocious Puberty poss treatments?
- GnRH analougues to suppress puberty until 12
- surgery, radio/chemotherapy
- case by case
What do 33% of Central Precocious Puberty cases have a..
-hypothalamic harmatoma (most benign) a focal malformation resembling a neoplasm
Peripheral Precocious Puberty is gonadotrophin independent and there is a loss of consonance. Hormone levels?
- less FSH/LH
- more E2/testosterone
Name 3 causes of Peripheral Precocious Puberty aka pseudo
- testotoxicosis: activating mutation of the LH receptor hence early androgen production. No FSH increase (no spermatogenesis)
- Sex steroid secreting tumour/exogenous intake
- CAH - adrenal androgens excess
- Mc Cune Albright S.
-Mc Cune Albright S. is a rare genetic condition. Is a constiutive activation of…
Symptoms..
Adenyl cylase, you get hyperactivity of signalling pathways
-cafe au lait skin, fibrous dysplasia of bone, hormone issues
Pubertal Delay no secondary sexual maturation by..
-14 in boys, 13 in girls/no period by 18
What is the commonest cause (90%) of pubertal delay?
-constitutional delay (affects growth and puberty. 10x more common in boys. Often hereditary. Can be 2rdry to disease.
What is hypogondaotrophic hypogonadism? Causes?
- low FSH/LH.
- hypopituitarism, impaired gonadotrophins, opiod use, steroid use, genetic causes
Explain a genetic Cause of Hypogondaotrophic hypogonadism?
Kallman’s syndrome. X linked KAL gene–>impaired GnRH migration neurone. Anosmia also presents.
What is hypergondaotrophic hypogonadism? Give an example of a condition with this of each sex, and name one viral cause.
- Gonadal dysgenesis, low steroid levels, low negative feedback so gonadotrophins increase a lot
- Congenital Klienfelters (XXY) 1:500 males
- Turner’s (XO) 1:3000 females
- Viral = Mumps
