How does the respiratory system maintain homeostasis?

Homeostasis is maintained by the respiratory system in two ways: gas exchange and regulation of blood pH. Gas exchange is performed by the lungs by eliminating carbon dioxide (CO2), a waste product given off by cellular respiration. As CO2 exits the body, oxygen needed for cellular respiration enters the body through the lungs. ATP, produced by cellular respiration, provides the energy for the body to perform many functions, including nerve conduction and muscle contraction. Lack of O2 affects brain function, sense of judgment, and a host of other problems.