What is Respiratory system?
:''For the biochemical process, see [[respiration]]'' [[File:Human respiratory system-NIH.PNG|right|370px|]] The '''respiratory system''', also called the '''gas exchange system''', is the body getting rid of [[carbon dioxide]] and taking in [[oxygen]]. Carbon dioxide, a waste product, goes out of the body. Oxygen, which the body needs, comes in. In humans the [[lung]]s are the main organ to do this. In other words, the way oxidation of organic compounds happens in cells and energy is released is called the respiratory system.<ref>{{Cite web|title=Respiratory System Human {{!}} Parts And Functions- Crack Your Target|date=15 June 2020|url=https://www.crackyourtarget.com/respiratory-system-human.html|access-date=2021-06-22|language=en-GB|archive-date=2021-06-24|archive-url=https://web.archive.org/web/20210624205733/https://www.crackyourtarget.com/respiratory-system-human.html|url-status=dead}}</ref> The first step is breathing in air, or [[inhalation|inhaling]] (inspiration). Inhalation means bringing air rich in oxygen into the body. [[Aspiration|Exhalation]] means giving out air rich in carbon dioxide from the body. The second step is gas exchange in the [[lungs]] where oxygen is [[diffusion|diffused]] into the blood and the carbon dioxide diffuses out of the blood. The third step is [[cellular respiration]], which makes the [[chemical energy]] that the cells in the body need, and carbon dioxide. Finally, the carbon dioxide from [[cellular respiration]] is breathed out of the body from the lungs. == Breathing == [[Breathing]] is the first step in the process of respiration. For respiration to happen, the body needs a constant supply of oxygen, which is done by breathing. [[Inhalation]] is the breathing in of air. To inhale, the lungs expand, decreasing the air [[Pressure in liquids|pressure]] in the lungs. This is caused by two actions. The [[diaphragm]] (a sheet of muscular tissue that separates the lungs from the abdomen) is pulled downward. Also the [[Muscle|muscles]] between the [[ribs]] contract to e