Intrapulmonary pressure, is known referred to as alveolar pressure. It is the pressure within the lung. When the glottis is not closed, the alveolar pressure is seen to be equal to the pleural pressure (the negative suction pressure that occurs between the thin layers of pleura) since no air is flowing into the lungs.
It is important to note that rapid and larger changes in lung volume will lead to a larger, positive intrapulmonic pressure changes.
