part of part of organ respiration organ EMAPA:17607 Organ that functions in gaseous exchange between an organism and its environment. In plants, microorganisms, and many small animals, air or water makes direct contact with the organism's cells or tissue fluids, and the processes of diffusion supply the organism with dioxygen (O2) and remove carbon dioxide (CO2). In larger animals the efficiency of gaseous exchange is improved by specialized respiratory organs, such as lungs and gills, which are ventilated by breathing mechanisms. SPD:0000428 TGMA:0001247 UBERON:0000171 apparatus respiratorius organ breathing organ gas exchange organ organ of apparatus respiratorius organ of respiratory system respiratory organ respiratory system organ uberon respiratory system