Also known as a sternutation, a sneeze dispels irritating particles from the nose. Dr. Pamela Georgeson describes a sneeze as "a sudden violent spasmodic audible expiration of breath through the nose and mouth, especially as a reflex act."
A sneeze begins with the release of signal chemicals like histamine or leukotrienes, which are manufactured by inflammatory cells. Several substances can cause the release of these chemicals, including allergens, viruses, smoke, pollution, perfumes, and other particles.
In the case of an allergy-induced sneeze, IgE antibodies must be present; they cause blood vessels in the nose to leak fluid, which in turn causes an itching sensation and stimulates nerve endings. This nerve stimulation triggers a reflex response in the brain.
The "sneeze center" is located in the brainstem, the lower part of the brain that connects to the spinal cord and regulates several automatic activities like breathing, pain sensitivity - and sneezing! Damage to the brain stem can result in the inability to sneeze.
A sneeze can expel 40,000 droplets into the air at speeds well over 100 mph; some have been estimated to travel at over 600 mph! A sneeze is the perfect vehicle for the wide transmission of diseases from Viruses, bacteria, and other microbes in the nose.
When you feel a sneeze coming, try to avoid sneezing onto your hands; grab a tissue instead! After your sternutation, dispose of the tissue properly and wash your hands. This will greatly reduce the transmission of germs.
How to Prevent Sneezing Fits
Medications can help prevent sneezes. Antihistamines, for example, block the action of histamine, and decongestants loosen congestion in the nose; both of these drugs can mute the sneeze reflex.
Your eyes are always closed when you sneeze. (Note: Adam Savage of Discovery Channel's Mythbusters recently proved that it is possible to sneeze with your eyes open - by holding them open. No, his eyes did not pop out of his head - but don't try this at home; it could cause serious injury.)
If you try to stop a sneeze by pinching your nose, you could rupture an eardrum by forcing the sternutation into the eustachian tube (which connects the throat and inner ear).
Thomas Edison used his early movie camera (kinetoscope) to film and study sneezes. "Fred Ott's Sneeze" by Thomas Edison was the first motion picture to be copyrighted in the United States.
Pepper is known for making people sneeze; it contains the irritating chemical piperine.
Some people have a "photic sneeze reflex" and are stimulated to sneeze by bright light.
"Snatiation" is a medical disorder in which a full stomach causes uncontrollable sneezing.
The human nose produces an estimated one to two pints of mucus per day.
Sneeze Onomatopoeia from Around the World
In the U.S. "achoo!" represents a sneeze. Here's a look at sneeze onomatopoeia from around the world, which suggest that a sneeze sounds like a sneeze no matter where you go:
Finland - "atsiuh!"
France - "atchoum!"
Germany - "hatschie"
Italy - "etciu!"
Japan - "hakushon!"
Poland - "apsik!"
Portugal - "atchim!"
Romania - "hapciu!"
Spain - "achu!" or "hachis!"
Sweden - "atjo!"
Turkey - "hapsu!"
Bonus: Sneezing Panda Video
Allergies and sneezes aren't limited to humans. Check out the sneezing panda video below. Added to youtube.com over a year ago, this short video has already been viewed over 10 million times!