The Respiratory System's primary function is to supply the blood with oxygen in order for the blood to deliver it to all of the parts of the body. Structures like the windpipe, lungs, bronchial tubes, and capillaries help the Respiratory system carry out its functions. Humans get oxygen to the blood through a process of inhaling oxygen and exhaling carbon dioxide called breathing. This oxygen enters the body through two main sources; the mouth and the nose. It then goes through a complex system to reach the air sacs in the lungs. The blood has already been filled with waste, and exits the body the same way it came in, where it then is released as carbon dioxide.
The Lungs