Breathing is a set of processes of decomposition and oxidation of organic substances that provide living organisms with energy.
In any living organism, the main source of energy is adenosine triphosphoric acid (ATP).
ATP is synthesized in cells due to energy released during the oxidation of nutrients. In the human body, ATP is formed mainly in the mitochondria as a result of aerobic (oxygen) oxidation. Therefore, the cells of our body constantly require oxygen, and one of the products of oxidation is carbon dioxide. The supply of oxygen to the body and the removal of carbon dioxide formed as a result of the conversion of substances is provided by the respiratory system.
Respiratory organs provide:
external respiration, i.e. ventilation of the lungs (intake and excretion of gases);
gas exchange in the lungs (the flow of oxygen from the air into the blood, and carbon dioxide from the blood into the exhaled air);
transport of gases by blood;
gas exchange in tissues (the flow of carbon dioxide from tissues to blood, and oxygen from blood to tissues);
tissue respiration (oxidation of organic substances in cells and ATP synthesis).
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.