During inspiration, intra-alveloar pressure is atmospheric pressure. - The tidal volume is the amount of fresh air that reaches the alveoli plus the dead space volume - The intra-alveolar pressure when the diaphragm contracts is the intra-alveolar pressure when the diaphragm relaxes. - The partial pressure of carbon dioxide in the blood leaving the lungs via the pulmonary vein is the partial pressure of carbon dioxide in the alveolar air. - At normal partial pressures in the capillaries, the percent of carbon dioxide in the blood that is bound to hemoglobin is the percent of oxygen in the blood that is bound to hemoglobin.