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.
For the parent of a young baby or toddler, it's easy to miss the signs of nasal allergies. A lot of parents don't realize, says Neeta Ogden, MD, an allergist in Closter, N.J. They assume that the constant runny nose and sneezing are just what happens when a child's exposed to day care germs..