The movement of air is dependent upon pressure gradients, with air moving from high pressure to low pressure. The flow of air is determined by the pressure gradient and the resistance to flow 2.
Resistance is determined by radius of the tube.
Boyle's Law 1. Pressure Gradients 1. Air flows in and out of the lungs due to air pressure differences inside and outside of the lungs. Generating Pressure Gradients in the Lung a. Lung pressure is decreased by increasing lung volume.