RESPIRATORY SYSTEM SUMMARY Nitrogen 78% COMPOSITION OF AIR Oxygen 21% Argon 0.93% CO2 0.038% Others 0.008% INHALED & EXHALED AIR inhaled air nitrogen (78%) oxygen (20%) carbon dioxide (0.04%) Other gases exhaled air nitrogen (78%) oxygen (16%) carbon dioxide (4%) Other gases Exhaled air contains less O2, but much more CO2 Respiratory system Mechanical respiration Inhalation Exhalation Cellular respiration Glucose+O2?CO2+H2O+ATP(energy) Respiratory system Mechanical respiration Inhalation Exhalation Cellular respiration Glucose+O2?CO2+H2O+ATP(energy) MECHANICAL RES: INHALATION ? Also termed inspiration ? Diaphragm contracts and flattens. ? Internal intercostal muscles relaxes