Answer
Gas flows to the alveoli and from it. It is proportional of the differnce in pressure from the external atomosphere and the alveoli. When there are small difference in pressure can result in large amounts of gas to flow in. When the thoracic volume rises, the intraplmonary pressure reduces. This then lets air flow into the lungs. When the lungs finally recoil the thoracic decreases and the intrapulmonary pressure increases and all the gases in the lungs comes out.
Work Step by Step
Gas flows to the alveoli and from it. It is proportional of the differnce in pressure from the external atomosphere and the alveoli. When there are small difference in pressure can result in large amounts of gas to flow in. When the thoracic volume rises, the intraplmonary pressure reduces. This then lets air flow into the lungs. When the lungs finally recoil the thoracic decreases and the intrapulmonary pressure increases and all the gases in the lungs comes out.
