LEARNING OUTCOME Define puberty. Identify factor regulating puberty. State the stages of puberty. Compare secondary sexual characteristics between male and female. Relate hormonal levels with stages and characteristics of puberty.
Stages of physical maturation which an individual become physiologically capable of sexual reproduction. It is physiological phase lasting 2 to 5 years, during which the genital organs mature. PUBERTY MSJ
Biological changes : Neurosecretory factor and hormones Modulation of somatic growth Initiation of development of sex gland Physical changes: Female secondary sex characteristic Male secondary sex characteristic PHYSIOLOGICAL CHANGES
MSJ PHYSIOLOGICAL CHANGES
At puberty: Brain maturation increase GnRH secretion Stimulate an increase in sex steroid function Stimulate increase in testosterone and estrogen Produce secondary sex characteristics . Features that appear during puberty, especially those that distinguish the two sexes of a species (not directly part of the reproductive system). ONSET OF PUBERTY
FSH and LH secretion high in newborn, but fall to low level in few weeks . ACTIVATION OF HYPOTHALAMUS- PITUITARY-GONADAL AXIS
Height and weight ratio (nutritional factor). Maturation of hypothalamus. Increase neurotransmitter output in CNS. Onset of adrenal androgen activity. FACTORS AFFECTING THE INITIATION OF PUBERTAL DEVELOPMENT
HORMONES INVOLVED IN PUBERTY HORMONE ENDOCRINE GLAND EFFECTS Testosterone Interstitial cells in testes Spermatogenesis; development of secondary sex characteristics Oestrogen Ovarian follicles in ovaries Development of secondary sex characteristics; menstrual cycle Progesterone Corpus luteum Development of secondary sex characteristics; menstrual cycle
Activation of hypothalamic-pituitary gonadal axis, Induces and enhance progressive ovarian and testicular sex hormones secretion. Sex steroid production: Appearance and maintenance sex characteristics Capacity for reproduction. Physical changes: Puberty proceed through FIVE stages from childhood to full maturity (P1-P5) (Marshall & Tanner) Reflect the progressive modification. PHYSIOLOGY
PUBERTAL CHANGES IN MALES Hypothalamic sensitivity to gonadal steroid negative feedback decreases leading to increased GnRH secretion . Pituitary sensitivity to GnRH increases , leading to increased LH and FSH secretion (reset gonadostat). Increased serum LH and FSH levels, leading to increased Leydig cell number and activity which lead to androgen secretion . Increased androgen secretion resulting in anatomic and physiologic changes typical of puberty. MSJ
PUBERTAL CHANGES IN FEMALES Hypothalamic sensitivity to gonadal steroid negative feedback decreases leading to increased GnRH secretion .
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- secondary sex