Respiration is the term used to refer to the movement of oxygen into your body and tissues and the movement of carbon dioxide from your body to the environment.Different organisms have different modes of respiration and respiratory systems.he basis of respiration or gas exchange is called a pressure gradient. Remember that substances tend to move from an area of higher concentration to an area of lower concentration. This is also called diffusion. This is true for the two gases essential for respiration—oxygen and carbon dioxide.