THE HUMAN BODY
You have seen many wonderful
things man has made. Can you name some what you have seen recently? None of the
things you can name are as wonderful as the human body. The part of the body
that guides and directs it is the brain. Do you see why the brain must be
protected against damage? You can tell that a bony layer lies beneath the hair
and skin of your head. You can feel it. Your brain is protected by this layer
of bone. This layer of bone is part of the skull. Are other important parts of
your head protected by these layers of hair, skin and bone? Can you name some?
Your heart and lungs also
lie within a bony framework. This bony framework is your chest. It, too, is
covered by layers of skin and of flesh. How do these layers protect the bones
that lie beneath them? Your skin and hair, the layers of flesh beneath the skin
and the bony framework of your body protect vital parts. But your body has
other forms of protection. Its ability to avoid harmful things is one of its
best defenses. All of your senses, for example, give warnings of possible
dangers. You use these warnings in deciding what action to take to avoid
getting hurt. Sometimes your body takes action before you are able to think
about what to do. Your eyelids, for example, close immediately when a
fast-moving object comes toward your eye. Your hand is immediately jerked away
from a hot object. Think of other things your body does to protect itself, even
before you think about what to do. Some of the things that can harm your body
are very small. These you can see only under a powerful microscope. Some of
these things are non-living. Some are living and are therefore either plants or
animals. Many of the tiny things that can be harmful are called germs.
Your body has forms of
protection against germs. But sometimes the germs overcome some of the defenses
of the body. They get inside your body. There they live, grow and produce more
of their own kind. They begin to harm the body. Warning signals are sent to the
brain. Sometimes these signals are pain signals. There may be other signals
too. These include fever, chills and sneezing. As warning signals reach the
brain, other body defenses go to work. They must overcome the germs. Otherwise,
great damage may be done.
HOW SENSE ORGANS ARE USED
Most of the foods you like
are foods that your body needs for growth and energy. Your senses are important
in the selection of food.
Your senses not only help
you choose foods your body needs; they also help you avoid foods that may be
harmful. Meat that has begun to spoil often has a bad odor. It may also have a
bad taste. Sometimes it may even look unfit to eat. Disturbances relayed to
your brain from nerve endings in your sense organs can help protect you from
food that may be harmful. Of course, you are only warned by senses. You must
still decide what to do about the warnings.
SAFEGUARD AGAINST INJURY
The smell of wood smoke
within a room may cause you to become alarmed. The gases and particles given
off by the burning wood go into the air. They reach your nose. Some of the
nerve endings there set up disturbances which are transmitted to your brain.
You become aware of the smoke and think of fire. You may decide to do one of
several things. Perhaps you will decide to give an alarm for others to hear. Or
you may see a smoking log in the fireplace and decide that there is no reason
to become alarmed. Perhaps you will decide to go into the open air. You will
certainly do whatever is necessary to protect yourself from harm. Whatever you
decide will depend a great deal upon what you learn through your senses.
All about you are things
that could harm your body. You become aware of these things because the nerve
endings in different sense organs become disturbed by the light, sound, odor,
or touch of these things.
Sometimes the amount of
disturbance of the sense organs is great enough to cause harm to the sense
organs themselves. Then your body defenses take over. Suppose, for example,
that a fast-moving object comes toward you. Your sense organs are disturbed by
its sound and appearance. You may duck or dodge. Your eyelids may close.
Perhaps you will cover your ears with your hands.
PROVIDING PLEASURES
Have you rubbed the soft fur
of a kitten? Did the kitten's fur feel pleasant to your touch? What are some
other pleasures you enjoy because of your sense of touch?
Each of your senses provides
you with pleasant experiences. You enjoy seeing the face of a friend. You also
enjoy seeing a beautiful sunset or picture. Smelling the odor of a cake being
baked is also enjoyable. Many people find music pleasing. Which of your senses
do you use when enjoying music?
EYES: Look
at the eyes of one of your classmates. Notice how the eyes are set in the head.
Is it possible to strike a person over his eye without touching the eye itself?
Feel the hard bony surface that lies beneath the skin that surrounds your eyes.
Do you see that the eyes are well protected against blows? What other natural
protection do your eyes have? Did you name the eyelids, eyebrows, eyelashes and
tear glands?
What other things besides
moving objects can harm the eyes? Do you know that too much light energy can be
harmful? For this reason avoid looking directly at very bright lights. Sun
lamps and heat lamps can also be harmful to the eyes. For this reason do not
look directly at them. Because the same type of energy comes from the sun, you
should not look directly at the sun.
NOSE:
Which of the nerve endings that lie within your head have the least protection?
Might they be those of your sense of smell? Where are these nerve endings? Do
you see why baseball catchers wear masks? Do you see why players in other
sports also are encouraged to wear nose guards?
The nose and all of the
other sense organs have natural protections. These protect against many dangers
which might cause damage to the sense organs. You can add to the natural
protections by doing everything possible to give proper care and protection to
your sense organs.
No comments:
Post a Comment