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decorative star graphic  Adolescence:
Biosocial Development
- Puberty Begins -

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Girls Age Boys
Ovaries increase production of estrogen & progesterone 9  
Uterus & vagina begins to grow larger 9 1/2  
Breast "bud" stage 10 Testes increase production of testosterone
Pubic hair begins to appear 11 Testes & scrotum grow larger
Weight spurt begins 11 1/2  
Peak height spurt 12 Pubic hair begins to appear
Peak muscle & organ growth - Hips become noticeably wider 12 1/2 Penis growth begins
Menarche (1st menstrual period)    
  13 Spermarche (1st ejaculation)
    Weight spurt begins
1st ovulation 13 1/2  
  14 Peak height spurt
  14 1/2 Peak muscle & organ growth - shoulders become noticeably broader
Pubic hair pattern 15 Voice lowers
Full breast growth 16 Readily visible facial hair
  18 final pubic hair pattern

Hormones & Puberty - The HPA axis (Hypothalamus/Pituitary/Adrenal)

From the Hypothalamus

via hormones to the Pituitary

via GH hormones

via GnRH hormones

to the adrenal glands

to the gonads (ovaries & testicles)

Causes an increase in many hormones including Testosterone & Estrogen

Growth spurt - Primary sex characteristics - Secondary sex characteristics

Ψ  To some extent hormonal changes cause emotional change, in that

     •  rapidly increasing hormone levels, especially testosterone, cause more rapid arousal of emotions.
      •  Hormones affect the quick shifts in the extremes of emotions.
       •  For boys, hormonal increases lead to more thoughts about sex, etc.
        •  For many girls, the menstrual cycle produces mood changes.

Ψ  The age of puberty is highly variable, factors that affect its onset are

    •  stress - causes early puberty.
     •  genes - mother daughter correlation.
      •  body type - stocky individuals earlier.

Growth & Development
Robert C. Gates
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