175 puberty Flashcards
puberty
maturation of hypothalamus (GnRH) –> pituitary (LH/FSH) –> gonads (sex steroids - estrogen/androgen/etc)
what happens in puberty?
increased GnRH secretion (freq and amp) at night then day –> increases LH/FSH (night then day) –> increased estradiol and testosterone
when des puberty debing?
At 11 to 20 weeks of gestation, GnRH increases until suppressed by maternal estrogen –> at birth mother estrogen goes away –> birth LH/FSH go up again (mini-puberty at birth - might see breast development and can measure gonadtropins to see if normal at this stage only) –> 6 months then LH/FSH go down (due to GnRH supression) and stay down until adolescence when normally puberty occurs
Adrenarche
awaken off adrenal gland (biochemical, not physical)
maturation of hypothalamic - pituitary - adrenal axis
adrenal androgens, DHEA increase
independent of puberty at ~6 yrs
1st physical changes of puberty
women - breast development at ~ 10 years (menarche of ~12.5 years)
boy - testicular enlargement at ~
physical changes in girls at puberty
breast and pubic hair development is seperate
breat - estrogen
pubic hair - testorone
staging of breast tissue
tanner stage 1 - prepuberty
2 - slight tissue under aerolar
3 - extends behind aerolar
5 - follow mature
staging of pubic hari
tanner 1 - no 2 - along each side of labia 3 - coarser and over monds 4 - extends towards thighs 5 - full
peak growth occurs when for girls?
growth - tanner 3 of breast stage
menarche - tanner 4 of breast stage
growth first then menarche
avergae puberty in boys
~11.5 (9-15)
stages in boys
pubic hair
1 - no hair
changes in boys during puberty
gynecomastia at tanner 2-3
voice change tanner 3-4
peak growth tanner 4
facial hair 4-5
testicular and genital growth then growth
peak growth of boys vs girls
girls at tanner 3
boys at tanner 4
timing of puberty
reactivation from earlier
don’t know what makes it start
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KAL1 –> gene for CNS adhesion for GnRH, olfactory
Neurokinin B –> Kiss1 –> kiss1 peptin; increases with puberty in hypothalamus; binds to GPR54 receptor which is required for puberty
Leptin - E balance signal from fat; suppresses food intake; puberty won’t occur if there isn’t leptin around)
– (inhibitory)
MRKN3 - decreases at puberty thus allowing puberty;
variations of normal puberty
premature adrenarche (< 6 years) - can make enough testosterone to cause physical changes –> pubic hair, acne
premature thelarche - premature breast tissue (occurs with obesity); adipose can aromatize testosterone to estrogen and cause development
constitutional delay of puberty - usually genetic/hereditary; will have normal puberty, just late
