Lung pressure change curve

The AB section of the curve (1) shows the change of air pressure in the inspiratory lung, and the sternum and ribs move upward and outward. At the same time, Figure 2 should be in B state, and the diaphragm is in contraction state.

(2) The difference between the intrapulmonary pressure and the BC section of the curve is positive, which means that the intrapulmonary pressure is higher than the outside atmospheric pressure, and it is an exhalation process, and the diameter of the thoracic cavity decreases. At this time, the muscles related to breathing are in a relaxed state.

(3)AB is the inspiratory process and BC is the expiratory process. Therefore, in this breathing, the moment when inspiration ends is the moment of B and B in the coordinate system or the moment when expiration begins. At this time, the pressure difference between lung pressure and atmospheric pressure is 0, which means that lung pressure is equal to atmospheric pressure. Neither inhale nor exhale.

So the answer is:

(1) breathe in; b； shrink

(2) relax; shrink

(3)B； (to) equal to ...