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20 Cards in this Set
- Front
- Back
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ethnic disparities in onset of puberty and menarche
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blacks first, then Hisp, then NH whites
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hypo-pit-gonadal axis in embryo-->kids
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2nd trimester fetus:
-arcuate nucleus of hypothalamus has autorhythmicity: secretes GnRH in pulsatile manner (every 60-90 min) -fetal gonadotropin levels peak at midgestation, then decline to low levels at term -gonadotropin levels decline to nadirs at age 3 in boys and 4 in girls & remain low til onset of puberty |
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first measurable event indicating onset of puberty;
what causes it? |
incr gonadotropin (LH, FSH) secretion during sleep (d/t reactivation of pulsatile GnRH from hypo)
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endocrinologic marker of adult reproductive fxn in women
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development of positive feedback (=ability of pituitary to respond to high levels of sex hormones with surge of secretory activity--i.e. surge of LH)
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what trigges ovulation and luterinization of follicle
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LH
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adrenarche
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-happens before puberty (6-9 y/o)
-refers to changes in adrenal cortex -increased activities of: A. 17-20 desmolase (First Aid, p. 263: converts cholesterol-->pregnenolone and initiates production of all adrenal sterids) B. 17-hydroxylase (allows production of glucocorticoid and sex hormones) |
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what can lead to hirsutism
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abnl adrenarche: xs adrenal androgen production
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what can lead to hyperandrogenic chronic anovulation (polycystic ovary syndrome)
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abnl adrenarche: xs adrenal androgen production
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what alloows gonadotropin prodution to incr during puberty
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CNS becomes less sensitive to gonadal negative feedback ("resetting the gonadostat")
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what is necessary for puberty to begin
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1. critical weight & body fat (24%)
2. leptin (necessary but not sufficient signal for pubertal onset) also, hyperinsulinemia and insulin resistance can cause early onset puberty |
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first sign of puberty in girls
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breast budding
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first sign of puberty in boys
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enlargement of gonads (followed soon by enlargement of phallus)
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progression of puberty in girls
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1. breast budding
2. pubic hair 3. menarche |
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progression of puberty in boys
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1. enlargement of gonads
2. enlargemet of penis 3. pubic hair 4. first ejaculation of semen (spermarche) (parallel's girls progression: 1. enlargement of breasts (breast budding) 2. pubic hair 3. menarche) |
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when does axillary hair develop
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(both boys and girls)
2 yrs after pubic hair |
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Tanner stages
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Stage 1:
-female breast: elevation of papillae (nipple) only -pubic hair: vellus hair -male genitalia: preadolescent Stage 2 (1st sign of puberty) -female breast: breast bud (=1st sign of puberty), enlargement of areola (colored area surrounding nipple AKA papillae) -pubic hair: sparse, straight hair on labia -male genitalia: ENLARGED TESTES (=1st sign of puberty), scrotal skin changes texture Stage 3: -female breast: further enlargement, no separation of contours -pubic hair: coarser hair to jxn of pubes -male genitalia: PENILE ENLARGEMENT (first length, then breadth) Stage 4: -female breast: projection of areola & papilla above breast -pubic hair: adult hair, but not on inner thighs -male genitalia: dev of glans penis, darkened scrotal skin Stage 5: -female breast: mature, recession of areola -pubic hair: mature; spread to inner thighs -male genitalia: mature |
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how do gonadal steroids affect pubertal growth
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1.incr GH
2.incr IGF-1 (liver, cartilage, bone) |
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somatic growth in girls vs. boys
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Girls begin pubertal growth 2 yrs earlier than boys. Thus:
1. girls are shorter at onset of accelerated growth. 2. lnger period of prepubertal growth in boys, so boys end up taller |
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what determines adult height
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1. child's height at pubertal onset
2. amplitude of growth spurt |
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skeletal maturation in boys vs. girls
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biacromial diameter increases much more in boys, while biiliac diameter increases much more in girls
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