Our body is created perfectly. It has systems that protect it. It is only when it is abused or it ages that its functions degenerate. When a foreign body or microorganism enters our upper respiratory tract, we will sneeze. This is what happens. 1. T he receptors, which are nerve endings in our nasal passageways, detect the irritant. This irritant might be an unusual smell, dust, animal dander, pepper, microorganism (bacteria or virus, etc. ) that attack the mucous membranes or a variety of other substances. 2. Nerves carry these impulses to the sneezing center in our brain stem. 3. The sneezing center sends its instructions to our facial nerve and the nerves that lead to our lungs and diaphragm. 4. Our eyes start to water, and our nasal passageways secrete fluid. Our diaphragm moves abruptly, causing us to take a deep breath. Then the muscles in our chest contract, causing the air to leave our nose and mouth suddenly and...