ADOLESCENCE Determinants of Puberty

 ADOLESCENCE

Puberty is a period of rapid physical maturation involving hormonal and bodily changes that occur primarily in early adolescence.

The features and proportions of the body change as the individual becomes capable of reproducing.

 Determinants of Puberty:

Puberty is not the same as adolescence.

--as the most important marker for the beginning of adolescence.

 Puberty might begin as early as 10 years of age or as late as 13½ for boys.

It might end as early as 13 years or as late as 17 years.

 In fact, over the years the timing of puberty has changed.

For example, in Norway, menarche—a girl’s first menstruation—now occurs at just over 13 years of age, compared with 17 years of age in the 1840s.

 United States, where children mature up to a year earlier than in European countries.

 The normal range for the onset and progression of puberty for Girls occurs between the ages of 9 and 15.

 Precocious puberty is the term used to describe the very early onset and rapid progression of puberty.

 Judith Blakemore and her colleagues (2009) recently described the following characteristics of precocious puberty:

--pubertal onset occurs before 8 years of age in girls and before 9 years of age in boys.

--10 times more often in girls than in boys.

 It usually is treated by medically suppressing gonadotropic secretions, which temporarily stops pubertal change.

 The reasons for this treatment is that children who experience precocious puberty are ultimately likely to have short stature, early sexual capability, and the potential for engaging in age-inappropriate behavior.

Among the most important factors that influence the onset and sequence of puberty are heredity, hormones, weight, and body fat.

1. Heredity --Puberty is not an environmental accident. It does not take place at 2 or 3 years of age, and it does not occur in the twenties.

Programmed into the genes of every human being.

2. Hormones-- Behind the first whisker in boys and the widening of hips in girls is a flood of hormones.

Hormones are powerful chemical substances secreted by the endocrine glands and carried through the body by the bloodstream.

 It is controlled by the interaction of the

 The hypothalamus is a structure in the brain best known for hypothalamus, the pituitary gland, and the gonads (sex glands). -- monitoring eating, drinking, and sex.

 The pituitary gland is an important endocrine gland that controls growth and regulates other glands.

 The gonads are the sex glands—the testes in males, the ovaries in females.

 The key hormonal changes involve two classes of hormones  

--in males and females are: Androgens and Estrogens.

 Testosterone is an androgen that is a key hormone in the development of puberty in boys.

As the testosterone level rises during puberty, external genitals enlarge, height increases, and the voice changes.

 

Estradiol is an estrogen that plays an important role in female pubertal development.

As the estradiol level rises, breast development, uterine development, and skeletal changes occur.

 Are there links between hormones and adolescent behavior? Findings are inconsistent.

For example, one study found that social factors accounted for two to four times as hormonal factors in young adolescent girls’ depression and anger.

 Hormones do not act independently; hormonal activity is influenced by many environmental factors,

including parentadolescent relationships.

 Stress, eating patterns, sexual activity, and depression can also activate or suppress various aspects of

the hormone system.

 Growth Spurt: The rapid increases in growth since infancy.

The growth spurt associated with puberty occurs approximately two years earlier for girls than for boys.

(9 years of age for girls and 11 years of age for boys -USA).

 Boys and girls who are shorter or taller than their peers at the beginning of adolescence, girls are taller than boys, but later years most boys have taller than girls.

 

Sexual Maturation:

FOR BOYS: increase in penis and testicle size, appearance of straight pubic hair, minor voice change, first ejaculation (which usually occurs through masturbation or a wet dream), appearance of pubic hair, onset of maximum body growth, growth of hair in armpits, more detectable voice changes, and growth of facial hair.

 Three of the most noticeable areas of sexual maturation in boys are penis elongation, testes development, and growth of facial hair.

 FOR GIRLS:  First, on average the breasts enlarge and then pubic hair appears.

---the female grows in height, and her hips become wider than her shoulders.

Her first menstruation (menarche) occurs rather late in the pubertal cycle; it is considered normal if it occurs between the ages of 9 and 15.

 Pubertal females do not experience voice changes comparable to those in pubertal males.

By the end of puberty, the female’s breasts have become more fully rounded.

 

Body Image:

One psychological aspect of physical change in puberty is certain: Adolescents are preoccupied with their bodies and develop images of what their bodies are like.

 Preoccupation with body image is strong throughout adolescence and dissatisfied with their bodies than in late adolescence.

 Gender differences characterize adolescents’ perceptions of their bodies.

In general, girls are less happy with their bodies and have more negative body images than boys throughout puberty.

 As pubertal change proceeds, girls often become more dissatisfied with their bodies, probably because their body fat increases.

In contrast, boys become more satisfied as they move through puberty, probably because their muscle mass increases.

 Also some variations, keep in mind that there is considerable variation, with many adolescent girls having positive body images and many adolescent boys having negative body images.