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This content explores the physiological and hormonal changes during female puberty, including stages of development, body changes, growth spurts, and related factors like family, nutrition, and geographic location.
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Puberty Is the period which links the childhood and adulthood
Female Pubertal Developments Period: 4-5 years (1.5-6 years)
Female Pubertal Sequences: • Growth 9.8 years • Thelarche 10.0 years • Adrenarche 10.5 years • Menarche 12.8 years
Family Sex Nutrition Obesity Psychological Genetic General health Geographical location Exposure to the light Time of Puberty
Physiology of the female puberty Hormonal & physical changes
I- During childhood • Low levels of hormones (gonadostat): • GnRH • FSH&LH • Estrogen
Suppression of the Activity Levels of Hormones • Hypersensitivity of the Hypothalamus • Intrinsic CNS inhibition
II- During Adolescence • Increase levels of hormones: • Adrenal androgen (Adrenarche) • Gonadotrophic hormones (FSH&LH) • Estrogen (Gonadarche)
High Activity Levels of Hormones • Decrease sensitivity • Maturation of Hypothalamus • Increase amplitude & frequency of pulsative GnRH
The Release of Pulsative GnRH • Increase Gonadotrophic & steroids • Appearance of secondary sexual characteristics • Menarche • Ovulation (estradiol-LH)
Secondary Sexual Characteristics: • Breast development • Pubic and axillary hair growth • Female fate distribution • Vaginal and uterine growth • Skeletal growth
Growth Growth spurt, express as increase linear growth velocity in cm per year.
Growth • Peak: 2 years after breast budding • Height: reached maximum at age 17-18 years • Skeletal changes: * Insulin-like GF * Growth hormone * Sex steroid
Thelarche The earliest sign of of puberty to become evident is usually breast growth
Adrenarche The growth of pubic and axillary hair is due to increase production of adrenal androgen
Adrenarche • Increase androgen: 6-15 years • Is not under control of the following: * Gonadotrophin * ACTH * Prolactin
Tanner Staging The breasts and of pubic hair growth of puberty have been classified into five stages
Gonadarche • Factors which induce gonadarche in late pre-puberty: * Anterior pituitary response GnRH * Follicle reactivity to FSH&LH
The Age of Menarche is decline: • Improve nutritional status • Body weight (47.8 kg) • Percentage of fat (16-23%) • Obese girls (23-30%)
In summary Puberty • Increase levels of gonadotrophins&steroids • Appearance of secondary sexual characteristics • Pulsatile GnRH (10-16 years) • Central negative inhibition • Maturation of positive feedback