What Is the Respiratory System?

The respiratory system is the organs and other parts of your body involved in breathing, when you exchange oxygen and carbon dioxide.

https://www.webmd.com/lung/how-we-breathe

All the cells in your body need oxygen to work. As they take in oxygen, they release carbon dioxide, which is called a “waste gas.” It goes into you bloodstream and gets carried to your lungs. You breathe it out when you exhale.

This vital function is called “gas exchange,” and your body is set up to do it automatically.