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 mucus membranes of the nose or throat. It can be very bothersome, but is rarely a sign of a serious problem. Sneezing can be due to: 1  Allergy to pollen, mold, dander, dust (hay fever).