The process of breathing (respiration) is divided into two distinct phases, inspiration (inhalation) and expiration (exhalation). During expiration, the diaphragm relaxes, and the volume of the thoracic cavity decreases, while the pressure within it increases. As a result, the lungs contract and air is forced out.
Also question is, what causes air to flow in and out of the lungs during expiration?
In contrast, expiration is a passive process. As the diaphragm and intercostal muscles relax, the lungs and thoracic tissues recoil, and the volume of the lungs decreases. This causes the pressure within the lungs to increase above that of the atmosphere, causing air to leave the lungs.
What is the effect of breathing depth on lung volume?
Changes in lung volume and breathing pattern during exercise and CO2 inhalation in humans. These results suggest that the depth and rate of breathing in humans can be affected by not only phasic but also tonic components.