Because of the chemical nature of impulse and the axon-dendrite structure. Because of the chemical nature of impulse and the axon-dendrite structure. http://www.biologymad.com/nervoussystem/nerveimpulses.htm (Best technical explanation and excellent graphics and animations)
Newborns may sneeze, and this is typically attributed to the irritation of their nasal passages. The most common irritants, explains Dr. Iannelli, are smoke (and simply smoking outside is not enough), animal dander from pets in the house, dust mites, and mold.
What Causes You to Sneeze? Part of your noseâs job is to clean the air you breathe, making sure itâs free of dirt and bacteria particles. In most cases, your nose traps this dirt and bacteria in mucus. Your stomach then digests the mucus, which neutralizes any potentially harmful invaders.