NURS2003 Chapter Notes - Chapter 8: Secondary Sex Characteristic, Pubic Hair, Sex Organ
CHAPTER 8 – PHYSICAL DEVELOPMENT
Puberty
Puberty: the hormonal physical changes by which children become sexually
mature human beings and reach their adult height
Occur during early adolescence and there can be decades between the time
children physically mature and the time they full enter adult life
Puberty rite: a “coming of age” ritual, usually beginning at some event such as
first menstruation, held in traditional cultures to celebrate children’s transition to
adulthood
Because in traditional agrarian societies a person’s changing body used to be
the signal to get married, many cultures devised puberty rites to welcome
physical changes
Secular trend in puberty: a century-long decline in the average age at which
children reach puberty in the developed world
Magnified the separation between puberty and full adulthood
Menarche: a girl’s first menstruation
Spermarche: a boy’s first ejaculation of live sperm
Menarche and spermarche have been occurring at younger ages
2 hormonal command centres program puberty
Adrenal androgens: hormones produced by the adrenal glands that program
various aspects of puberty, such as growth of body hair, skin changes and sexual
desire
Produced starting in middle childhood
HPG axis: the main hormonal system programming puberty; it involves a
triggering hypothalamic hormone that causes the pituitary to secrete its
hormones, which in turn cause the ovaries and testes to develop and secrete the
hormones that produce the major body changes
Gonads: the sex organs – the ovaries in girls and the testes in boys
Testosterone: the hormone responsible for the maturation of the organs of
reproduction and other signs of puberty in men and for hair and skin changes
during puberty and for sexual desire in both sexes
Leptin levels and a variety of environmental influences trigger the initial
hypothalamic hormone
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The physical changes of puberty are divided into primary sexual characteristics,
secondary sexual characteristics and the growth spurt
Primary sexual characteristics: physical changes of puberty that directly involve
the organs of reproduction such as the growth of the penis and the onset of
menstruation
Secondary sexual characteristics: physical changes of puberty that are not
directly involved in reproduction
Breast development
Growth of pubic hair
Voice changes
Alterations in the texture of the skin
Growth spurt: a dramatic increase in height and weight that occurs during puberty
Although in females puberty begins with the growth spurt and menarche
occurs late in the process, the rate and sequence of this total-body
transformation varies from child to child
Because for males the externally visible changes of puberty occur later and
the organs of reproduction are the first to start developing, the puberty
timetable of the sexes are not as far apart as they appear to be
The striking individual difference in the timing of puberty are mainly genetically
programmed
African American children tend to reach puberty at a younger age
For girls, being overweight and having stressful family relationships are tied to
reaching puberty earlier
These “environmental events” push up the hypothalamic timer, but strangely,
only for females
How children feel about their changing bodies varies, depending on the social
environment
Breast development often evokes positive emotions
Feelings about menstruation seem more positive than in the past because
today’s mothers are more apt to celebrate this change
First ejaculation is rarely talked about
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