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Physio 2 Sexual Differentiation & Maturation

Terms in this set (20)

1) Sexual differentiation
-high LH & FSH levels independent of GnRH secretion

2) Immature Quiescence
-reduced hypothalamic GnRH release
-increased sensitivity to gonadal steroid feedback
Both of these cause Gonadotropin (LH & FSH) insufficiency

3) Phenotype of Puberty
Male:
defined as...
-Spermatozoa appear in epididymis
-testicle size increases
-somatic changes reflecting internal changes (spermatogenesis & androgen production)
Boys reach a maximum height growth of 10cm/year by age 11.

Female:
defined as (depends on species)...
-first ovulation
-menarche
-first estrus
-vaginal opening
Girls reach a maximum height growth of 9cm/year by age 10.

4) Endocrinology of Puberty
Central drive:
-increased GnRH release & Gonadotropin secretion => gonadal steroid production => increased osteoblast activity & eventually the close of epiphyseal plates
-Increased Gonadotropin pulse Amplitude (NOT frequency)
-increased serum Insulin-like Growth Factor I (metabolic signal to facilitate the onset of puberty)

Thelarche:
-breast development
-stimulated by increase secretion of estrogens
-hypertrophy comes from increased fat deposition and areola growth

Adrenarche:
-happens about 2 years before puberty
-DHEA & delta-4-androstenedione increase, causing development of auxiliary and pubic hair
-regulated independently of the hypothalamic-adrenal axis

Precocious puberty:
-may be GnRH-dependent or -independent
-Central Precocious Puberty (GnRH-dependent) is treated by long-acting GnRH agonist or specific GnRH antagonist so the pituitary will be desensitized and gonadotropin secretion will be suppressed
-it is a polygenic condition