3

Puberty, Health, and Biological Foundations

Puberty

• The period of rapid physical maturation involving hormonal and bodily changes that take place primarily in early adolescence

Feedback System of Sex Hormones

LH-RF (lutenizing hormone-releasing factor) and FSH-RF (follicle stimulating hormone-releasing factor) stimulate pituitary gland

LH (lutenizing) and FSH (follicle stimulating) stimulate gonads

(Testes in males, ovaries in females)

Fig. 3.3

The Endocrine System

• Hypothalamus– Structure in the brain– Secretes releasing factor

• Pituitary Gland– Regulates other glands– Secretes FSH and LH

• Gonads– Testes, ovaries– Secretes sex hormones

The Endocrine System

Major Endocrine Glands Involved in Pubertal Change

Fig. 3.2

Hormones

• Powerful chemicals secreted by the endocrine glands; carried through the body by the bloodstream.

Androgens: The main class of male sex hormones

Estrogens: The main class of female sex hormones

Adrenarche

• Involves hormonal changes in the adrenal glands, from about 6-9 years of age– Gonadarche: What most people think

of as puberty; involving sexual maturation and development of reproductive maturity

– Spermarche: A boy’s first ejaculation of semen

– Menarche: A girl’s first menstrual period

Growth Spurt

• Occurs 2 years earlier for girls (age 11.5) than boys (13.5) on average

• Girl increase 3.5 inches per year, boys about 4, during this period

• Weight gain follows roughly same timetable as height gain

• Girls gain hip width while boys gain shoulder width

Growth SpurtPubertal Growth Spurt

Fig. 3.4

Sexual Maturation

• Males

– Increase penis and testicle size – Pubic hair– Voice change– Spermarche – Armpit hair – Facial hair

Sexual Maturation

• Females

– Breasts enlarge – Pubic hair– Armpit hair– Menarche

Sexual Maturation

Fig. 3.5

Normal Range and Average Development of Sexual Characteristics in Males and Females

The Age at Menarche has Declined

Median Ages at Menarche in Selected Northern European Countries and the United States from

1845 to 1969

Fig. 3.7

Psychological Dimensions of Puberty

• Body Image• Hormones and Behavior• Menarche and the Menstrual Cycle• Early and Late Maturation• Are Puberty’s Effects Exaggerated?• http://www.youtube.com/watch?

v=Di2Tgx05EjM&mode=related&search=