(1) This picture demonstrates the process of respiratory movement. The bell jar C represents the thorax, the glass tube A represents the trachea, the balloon B represents the lungs (or alveoli), and the rubber membrane represents the diaphragm. (2) When the rubber membrane D is pulled down by hand, the volume of the bell jar increases, the internal air pressure decreases and the balloon expands. The air pressure in the balloon is lower than the atmospheric pressure. Air entering the balloon indicates the inhalation process. (3) When the rubber membrane D is pushed up by hand, it means that the diaphragm relaxes, the upper and lower diameter of the thorax decreases, the thorax shrinks, the lungs retract, the air pressure in the lungs is higher than the atmospheric pressure, the gas leaves the lungs, and exhalation is completed. When it is pulled down by hand, When the rubber membrane is D, it means that the diaphragm contracts, the upper and lower diameters of the thorax increase, the thorax expands, the lungs expand, the air pressure in the lungs is lower than the atmospheric pressure, and external air enters the lungs, completing inhalation.
So the answer is: (1) Trachea, lungs (or alveoli) (2) Expansion; inhalation (3) Diaphragm