The Respiratory SystemOkay. So every body is trying its hardest, in the face of internal and external stimuli, to maintain homeostasis (equilibrium). All of your systems do their damnedest to contribute to that. Your respiratory system, specifically, contributes to homeostasis by exchanging gases (commonly understood as O2 and C02, but others as well) between the atmospheric air, your blood, and the cells of your body's tissues.
Your respiratory system also helps adjust your body's pH to keep it at its normal, slightly alkaline 7.4. It also contains your olfactory receptors, and excretes small amounts of water and heat. (The heat mechanism is more noticeable in other mammals, such as dogs, whose skin does not assist in modulating their internal temperature: that's why they pant.)
( Long rambly explanation of my study notes below the cut. )More later...