Lung Volumes Partial Pressure of Gases Gas Exchange Oxygen Transport Effects of Acid on Oxygen Transport Carbon Dioxide Transport Chemical Control of Respiration Carboxyhemoglobin Back to Main Manual Index Respiration and Ventilation Definition of Respiration Respiration is the total process of delivering oxygen to the cells and carrying away the byproduct of metabolism, carbon dioxide. Respiration includes gas exchange in the lungs, circulation of gases through the blood stream, and transfer of gases at the cellular level.
Air is drawn into the air sacs of the lungs, where oxygen from the air can enter the blood.
Carbon dioxide exits from the blood into the alveolar air. The second half of respiration occurs when the blood reaches the tissues. Oxygen then diffuses into the cells, and carbon dioxide enters the blood. The blood then circulates back to the lung, where the process begins again. Definition of Ventilation Ventilation is the process of moving gases through the respiratory tract.