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.
So chances are that when your newborn coughs or sneezes, you will wonder and worry about what causes it; if it is an infection etc. However, before you rush your baby to the doctor, consider the following: Newborn sneezing is the only option to clear their nose.