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.
Sneezing is caused by irritation to the nose or throat. Generally, this irritation results from a physical or airborne irritant, such as dust or allergens. In cases in which your sneezing is caused by allergies, avoiding allergens or taking over the counter allergy medication may help resolve the sneezing.