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Flashcards in 175 puberty Deck (22):


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



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

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


abnormal puberty in girls - ages

precious < 8 years
delayed > 13 years


abnormal puberty in boys - ages

precious < 9 years
delayed > 15 years


bone age

can be different than actual age

due to estrogen in boys and girls


lab eval

can't measure GnRH

measure LH/FSH; sex steroids -- measure at morning because highest at night during early puberty


precocious puberty

central and peripheral

central -- GnRH --> LF/FSH; idiopathic in girls; boys have something wrong (CNS issue - trauma, hydrocephalus, tumors)

peripheral - (GnRH independent production of estrogen/testorone)
LH activating mutations - testicals can make testorone without activation
exogenous sex steroids


is precocoious puberty usually idiopathic in girls or boys


boys usually have a CNS abormality


delayed puberty

hypogonadotropic - no LH/FSH -
congenital: kallman (KAL1 mutation); septo-optic dysplasia (pituitary issue)
malnutrition, excessive exercise, chronic illness (low leptin)
endocrinopathies - hyperprolactinemia, cushing's

hypergonadoropic - super high LH/FSH but no sex steroids becuase gonads are bad
acquired - autoimmune, radiation
congenital - Klinefelter, gonad dysgenesis