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.