Page 108 - Science Class 08

Girls also experience puberty as a sequence of Pubic hair development are similar for both girls
events, but their pubertal changes usually
begin before boys of the same age. Each girl is
different and may progress through these
changes differently.
The following are average ages when puberty
changes may occur:
v Beginning of puberty: 8 to 13 years
v First pubertal change: breast development
v Pubic hair development: shortly a er
breast development
v Hair under the arms: 12 years old
v Menstrual periods: 10 to 16.5 years old
There are specific stages of development that
both boys and girls go through when develo-
ping secondary sexual characteris cs (the
physical characteris cs of males and females
that are not involved in reproduc on such as
voice changes, body shape, pubic hair
distribu on and facial hair).
The following is a brief overview of the changes
that occur:
In boys, the ini al puberty change is the
enlargement of the scrotum and testes. At this
point, the penis does not enlarge. Then, as the
testes and scrotum con nue to enlarge, the
penis gets longer. Next, the penis will con nue
to grow in both size and length.
In girls, the ini al puberty change is the
development of breast buds, in which the
breast and nipple elevate. The areola (dark
area of skin that surrounds the nipple of the
breast) increases in size at this me. The
breasts then con nue to enlarge. Eventually,
the nipples and the areolas will elevate again,
forming another projec on on the breasts. At
the adult state, only the nipple remains
elevated above the rest of the breast ssue.
108
and boys. These ini al growth of hair produce
long, so hair that are only in a small area
around the genitals. These hair then become
darker and coarser as they con nues to spread.
The pubic hair eventually look like adult hair,
but in a smaller area. These hair may spread to
the thighs and, some mes, up the stomach.
SECONDARY SEXUAL CHARACTER
Secondary sexual character helps to dis nguish
between male and female.
The boys begin to grow facial hair i.e.,
moustaches and beard. Some boys also
develop hair on their chest.
In girls, breasts begin to develop.
In both, boys and girls, hair grows under the
arms and in the region above the thighs or in
the pubic region.
1. Why the height of the members of a
family is similar?
2. How can we determine the height of a
boy or girl?
3. What is adam’s apple?
4. Why some boys and girls get pimples
during puberty?
5. Why should we not be anxious to see
the bodily changes during the puberty?
How do These Changes Occurs?
You have studied about the bodily and mental
changes that occur at the age of puberty. Do
you know how these changes occur?
These changes occur because of the secre on
of chemical substances by the endocrine
glands. These chemical substance are called
hormones. Hormones do not only cause these
changes but also control these changes.
Science-8