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

Time of Puberty Family Sex Nutrition Obesity Psychological

Genetic General health Geographical location Exposure to the light

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