What is in the HPA axis
Adrenal androgen secretion, increased fetal secretion, increased petuitory factor, increased adrenal androgens.
what does the increased adrenal andogens cause
armpit hair, pubic hair, acne, body odor
What hapens in the HPG axis
gonadarche secretions, Increased GNRH, increased gonadotropins, increased sex steroids, sleep associated LH secretions.
what are the 2 important changes that happen before puberty
1) Decrease in sensitivity of
hypothalamus and pituitary
to neg feedback
2) Increase in sensitivity of
gonads to FSH & LH
Explain how puberty works
slide 4
what effect does sex steroids have
increases GH secretions as well as sensativity to GH
what does androgens do in puberty
directly stilumulate longitudinal growth as well as muscle growth. androgens also converted to estrogen by armatase.
what does estrogens do during puberty
stimulate bone mineral deposition and osteoblastic activity. and promote epiphesyal and meta pheseal fusion
how important is the pubertal growth spurt, numbers
Accounts for 20-30% of final adult height and
50% of final adult peak bone mass
when do girls and boys peak thier height velociity
at breast stage 4 9cm/year
Boys peak height velocity 10.3 cm/yr at
Tanner genital Stage 4 (14 years of age)
why guys ttaller than girls
2 extra years of pre-pubertal growth
– greater peak height velocity
which gender has more muscle mass and why
Males have greater muscle mass due to higher peak
muscle growth velocity
who gets more changes in proportional fat and why
Females have increased proportionate amount of fat (68%
of mass is fat free versus 82% in males) in certain areas
due to estrogen
why do femals have wider hips
Special cartilage in hips that responds more to estrogen
