Connecting the p-type region to the negative terminal of the battery and the n-type region to the positive terminal corresponds to reverse bias. If a diode is reverse-biased, the voltage at the cathode is comparatively higher than the anode. Therefore, no current will flow until the diode breaks down.
When you breathe out, or exhale, your diaphragm relaxes and moves upward into the chest cavity. The intercostal muscles between the ribs also relax to reduce the space in the chest cavity. As the space in the chest cavity gets smaller, air rich in carbon dioxide is forced out of your lungs and windpipe, and then out of your nose or mouth.
When you inhale, the air goes through the bronchii in your lungs to blood vessels that connect to veins and arteries. These veins and arteries carry the blood throughout your body. When you exhale, the carbon dioxide goes out the same way, exiting your body through your nose and mouth.