How do we breathe?
Breathing is essential for all living beings. It is an
involuntary reaction that takes place continuously. Men, animals, birds,
insects and plants- all need oxygen, which they get form the air through
respiration. However, different creatures breathe in different ways. Some
breathe through lungs, some others breathe through their skin. The earthworm is
one animal that breathes through its skin. Do you known how man breathes and
what happens in the body during the process of respiration?
When diaphragm pulls down, it gives lungs more space to suck sufficient air, when it relaxes, it forces some of the air out of lungs.
We, human beings, inhale air through the nose or mouth.
The nose and mouth are jointed in the back of the mouth in an area called
pharynx. The air inhaled goes to the lungs through the windpipe. There are two
lungs in our body- one on each side of our chest. They are made up of tissues
shaped like soft bags. Each lung has millions of air sacs, which get filled and
enlarged when air is inhaled. When it is exhaled, they contract.
The energy releasing process, which utilize the oxygen
and produces carbon dioxide, is termed as tissue respiration or external
respiration. In man, external respiration is the process where by air is
breathed from the environment into the lungs to provide internal respiration.
The oxygen, which is inhaled, is circulated throughout
the body by the blood. It oxidizes the food materials. During the process of
oxidation, carbon dioxide, water and other substances are produced. The same carbon
dioxide is expelled when we breathe out. When we do some physical work or
exercise, we need more energy. For the production of more energy, we need more
oxygen. That is hwy the rate of breathing becomes fast when we do any hard work
or physical exercise.
Normally, a newly born child breathes 60 items per
minute. A 15 years old child breathes 20 times a minute and an adult 16 to 18
times. The rate of breathing is faster in adults than in old people. The
respiratory center in the brain controls the process of breathing. This center
is sensitive to the amount of carbon dioxide in the blood. If there is an
increase in carbon dioxide such as during exercise, this center sends signals
to control breathing. As a result, the person breathes faster.
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