The study of human anatomy and physiology is a crucial branch of Biology Topics.
Introduction to Respiration, Definition and Meaning
We need energy to walk, run, climb the stairs, wash clothes, and cook food. Even when we are talking, eating, reading, writing or sleeping, energy is required. The processes like digestion of food, beating of heart, and movement of ribs and diaphragm during breathing, etc., which take place inside our body also need energy for their working. In fact, we need energy to perform all the activities which maintain our life, and also to do work. We get this energy from the food which we eat.
The food has stored energy. The stored energy of food is released slowly during the process of respiration which takes place inside our body all the time (even when we are sleeping). It is this energy which is then utilised in carrying out various life processes and doing our work. Respiration is essential because it provides us energy from the food which we eat and digest. So, all the living organisms need to respire to get energy from food required for their survival.
Many times we see our parents insisting that we should eat food regularly. This is because food is like a fuel for our body which provides us energy to maintain our life and stay healthy. It is not only the human beings who need energy. All other animals and plants also require energy. We will now discuss the process of respiration and how it provides energy to human beings, other animals, as well as plants.
All the organisms (plants and animals) require energy for performing various activities and maintaining their life. This energy is obtained by the breakdown of digested food during the process of respiration. The process of releasing energy from food is called respiration. Respiration occurs in all the living cells. The process of respiration involves taking in oxygen (of air) into the cells, using it for releasing energy by burning food, and then eliminating the waste products (carbon dioxide and water) from the body. Most living things need oxygen (of air) to obtain energy from food. This oxygen reacts with the food (like glucose) present in the body cells and burns them slowly to release energy. This energy is used by the living things. The process of respiration can be written in the form of a word equation as follows :
During respiration, the energy-rich food (like glucose) is broken down by oxygen into carbon dioxide and water, and energy is released (see Figure). This energy is used up by the organism (plant or animal). In fact, respiration is a kind of slow burning (or slow combustion) of food at ordinary temperature to produce energy. During respiration, oxygen is taken in and carbon dioxide is given out. Thus, the process of respiration involves the exchange of gases: oxygen and carbon dioxide. The process of respiration is the reverse of photosynthesis. This is because photosynthesis is the making of food (like glucose) by absorbing sunlight energy, whereas respiration is the breaking of food (like glucose) to release energy.
There are two main parts in the process of respiration :
(i) Breathing (taking in oxygen from air and releasing carbon dioxide), and
(ii) Using oxygen in the cells of the organism for releasing energy from food (like glucose).
The air which we ‘breathe in’ is transported to all the parts of the body and ultimately to each cell of the body. In the cells, oxygen (of air) brings about the breakdown of glucose (food).
The process of breakdown of food in the cells of the body with the release of energy is called respiration. Since the process of respiration which releases energy from food takes place inside the cells of the body, it is also called cellular respiration. The process of cellular respiration is common to all the living organisms (humans, other animals as ell as plants). It takes place in all the cells of an organism.