Which process is defined as movement of air in and out of the lungs?

Which process is defined as movement of air in and out of the lungs?

• A. Pulmonary ventilation
• B. Gas exchange in lungs and tissues
• C. Diffusion
• D. Oxygen transport in blood

Answer: (A)

Movement of air into and out of the lungs is ventilation. This is the mechanical breathing process driven by the respiratory muscles (like the diaphragm and intercostals) that creates pressure changes in the thorax to draw air in during inspiration and push air out during expiration. This air movement refreshes the alveolar air so oxygen can be absorbed and carbon dioxide removed during gas exchange. Gas exchange happens at the alveolar–capillary interface, where oxygen moves from inhaled air into blood and carbon dioxide moves from blood into the inhaled air to be exhaled. Diffusion is the general mechanism by which gases move down their concentration gradients across membranes, which underlies gas exchange. Oxygen transport in blood describes how oxygen is carried, mainly bound to hemoglobin, to tissues throughout the body.

Movement of air into and out of the lungs is ventilation. This is the mechanical breathing process driven by the respiratory muscles (like the diaphragm and intercostals) that creates pressure changes in the thorax to draw air in during inspiration and push air out during expiration. This air movement refreshes the alveolar air so oxygen can be absorbed and carbon dioxide removed during gas exchange.

Gas exchange happens at the alveolar–capillary interface, where oxygen moves from inhaled air into blood and carbon dioxide moves from blood into the inhaled air to be exhaled. Diffusion is the general mechanism by which gases move down their concentration gradients across membranes, which underlies gas exchange. Oxygen transport in blood describes how oxygen is carried, mainly bound to hemoglobin, to tissues throughout the body.