Jong Beom Cho
What are some things that we cannot live without? There would be many answers: food, water, money, or perhaps even emotional values like love. However, there is one aspect of our lives that we all take for granted. It is respiration, which can be visually observed by the up and down movement of human chests and we cannot literally live without it. Although respiration itself may seem as a simple activity of inhaling and exhaling, the entire process of respiration is much more complicated and fascinating. In order to understand human respiration, we first must understand the purpose of respiration and then the two main types of respiration: external and internal respiration.
Understanding why respiration takes place is crucial to understanding its process. When people hold their breath for a long time, they usually say that they need more air. From this we can assume that the purpose of respiration is to gain oxygen from the air. However, the main purpose of respiration is not to gain oxygen but to remove carbon dioxide within our body. From this gas exchange of oxygen and carbon dioxide, human body produces energy required to sustain its life. Therefore, the purpose of respiration is to remove carbon dioxide from our body and consequently manufacturing energy that is necessary for sustaining life.
After understanding the goal of respiration, the bigger part of the respiration process, external respiration, can be understood. As mentioned earlier in the text, the goal of the respiration was to exchange oxygen and carbon dioxide inside our body. In order to do so, humans have specialized organ that does the job which is called lung. Human lung have numerous number of gas exchanging device called lung sacs. Lung sacs are distributed throughout the inner surface of the lung. When human inhale, the air is sucked into the lung and lung sacs exchange the inhaled oxygen in the air with the carbon dioxide emitted from our body which is then exhaled out of the lung. This process is easily observed by the up and down movement of our chest. This was the respiration in the big picture, exchange of gas. However, in a smaller level there is more complexity to respiration.
There was another purpose of respiration other than the gas exchange, supplying our body with energy. This process which is called, internal respiration takes action in much more microscopic level. Internal respiration is a process which cells use oxygen as a main energy source and emit carbon dioxide and water, therefore, this process is also called cellular respiration. Humans like most living organisms, gain energy in forms of ATP (adenosine triphosphate) from decomposing carbohydrate, protein, and fat through internal respiration. The energy producing process is conducted in following order: glycolysis, citric acid cycle, and electric transport system. Through these three chemical processes which happen at the different level of human body, total 32 ATP are created from one glucose molecule, ready to fuel our body. Had our body gain its fuel from external respiration, internal respiration is a process which then burns the fuel and producing energy that sustain human body.
Respiration takes action without knowing. Therefore, we are often unaware of how it functions and the purpose of the respiration. But respiration is the foundation of all our biochemical activity happening in the body. Respiration fuels us and also feed us at the same time. Although it happens in such a small scale making us hard to notice, it is still a fascinating process.