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Chapter 2 Your Growth and Development
Boys become stronger as their muscles
develop rapidly. Their shoulders widen and their
waists narrow. They reach adult height at about
age 21. Adolescent girls usually start their growth
spurt before adolescent boys. They grow rapidly
in height and weight. The average age for girls to
reach adult height is 17.
The adolescent growth spurt occurs at
puberty. Puberty is the time when reproductive
organs mature. Hormones bring about sexual
maturity and other physical changes within the
body. Chart 2-1 lists primary and secondary sex
characteristics
Reaching Physical Maturity
Factors such as accidents, disease, and illness
can prevent complete growth and development
from occurring. To avoid health risks, take
good care of yourself and get periodic physical
checkups. Get the rest you need. Get regular
physical activity. Avoid harmful substances and
activities. Take safety precautions. Make wise
decisions about what you do and where you go.
Eat healthful, nutritious meals. By doing so, you
should be able to reach physical maturity and
live a long healthy life, 2-2. These topics are so
important to your growth that whole chapters in
this book focus on these factors.
Intellectual
Development
A second area of growth is intellectual
development. Intellectual development refers
to the growth of the brain and the use of mental
skills. These include your use of words, numbers,
and ideas. You take information into your brain
through your five senses. What you see, hear,
taste, touch, and smell all provide information.
You then use this information to respond
emotionally and socially, as well as reason, solve
problems, make decisions, and think creatively.
The Parts of the Brain and
Their Functions
The diagram in 2-3 shows the different parts
of the brain and the main functions of each. There
appear to be three main areas. The brainstem
and cerebellum control action activities. The
limbic system controls emotion-related responses.
The cortex controls thinking responses. As you
mature, you develop the thinking part of your
brain so it controls your responses to your
environment.
‚ The brainstem controls life functions such as
the beating of the heart and breathing. The
brainstem is made up of different parts that
are involved in getting information out to
different body parts and producing a physical
response. When there is a threat to the body,
the brainstem controls the body’s responses
and ensures survival.
‚ The cerebellum controls automatic
movements. For instance, once you learn to
ride a bike, you do it automatically. You have
stored this information in the cerebellum and
use it automatically.
‚ The limbic system consists of four main
structures in the brain that control emotions
and hormone production as well as eating,
How could your daily choices affect your
ability to reach physical maturity?
Use What You Learn
2-2
Being active and adventurous is natural during the
teen years. Following safety precautions will help you
reach your physical potential.