We do a lot of activities like running, walking, working, etc. And for all these activities we require a lot of energy. How and from where do we get this energy?
The breaking down of food in the presence of oxygen releases energy and carbon dioxide. The inhalation of the required oxygen and the exhalation of the carbon dioxide are known as breathing.
Breathing serves as the pump for the lymphatic system, just as the heart serves the circulatory system.
Breathing is important for two reasons. It is the only means to supply our bodies and its various organs with the supply of oxygen which is vital for our survival. The second function of breathing is that it is one means to get rid of waste products and toxins from the body.
Animals take in high energy organic molecules in the form of food. The food is broken down in the presence of oxygen to produce energy. As catabolism occurs in the presence of oxygen it is referred to a oxidation.
A majority of the organisms on earth are called aerobes because their cells require oxygen for respiration. Cellular respiration involves utilisation of oxygen for the oxidation of food materials and for the production of energy for biological activities. The metabolic reactions involving the production and utilisation of energy result in the release of carbon dioxide in the cells; carbon dioxide being a toxic waste material has to be thrown out. The exchange of respiratory gases, oxygen and carbon dioxide, between the organism and the environment in which it lives is fundamental to aerobic mode of life.