Simulation of human lung respiration

(1) In the figure, A represents human trachea, in the figure, B balloon simulates human lung, and the rubber membrane at the bottom of the bottle represents diaphragm.

(2) Pull down D diaphragm by hand to demonstrate the inhalation state of human body: at this time, the thoracic volume of C expands → the lungs of B expand with the expansion → the air pressure in the lungs is less than the external atmospheric pressure → the gas is inhaled into the lungs.

(3) When coughing violently, it is a violent exhalation. At this time, the diaphragm is relaxed and the top of the D diaphragm rises.

So the answer is:

(1) trachea; lung

(2) expansion; Big; suck

(3) upward