Music: "Hell Is Everywhere"
"1994 - Zombie Invocation"
Sneeze (or sternutation) is a semi-autonomous, convulsive expulsion of air from the lungs. It occurs when a particle (or sufficient particles) passes through the nasal hairs and reaches the nasal mucosa. This triggers the production of histamines, which reach the nerve cells in the nose, which then send a signal to the brain to initiate the sneeze, which relates the initial signal and creates a large opening of the nasal cavity, resulting in a powerful release of air and bioparticles. The reason behind the powerful nature of a sneeze is its involvement of not simply the nose and mouth, but numerous organs of the upper body - it is a reflectory response that involves the muscles of the face, throat, and chest.
Sneezes are capable of spreading disease through the potentially infectious aerosol droplets that they can expel, which generally range from 0.5 to 5 µm in diameter. About 40,000 such droplets can be produced by a single sneeze. The speed of this release has been the source of much speculation, with the most conservative estimates placing it around 150 kilometers/hour (42 meters/second) or roughly 95 mph (135 feet/second), and the highest estimates -such as the JFK Health World Museum in Barrington, Illinois- which propose a speed as fast as 85% of the speed of sound, corresponding to approximately 1045 kilometers per hour (290 meters/second) or roughly 650 mph (950 feet/second).
In certain individuals, sneezing can also be triggered by sudden exposure to bright light, particularly that of the Sun, as well as the customary irritation of the mucosa -- a response known as the photic sneeze reflex.
A somewhat unusual alternative trigger of uncontrollable bursts of sneezing in particular individuals is the fullness of the stomach immediately after a large meal. This is known as snatiation and is regarded a medical disorder passed along genetically as an autosomal dominant trait.
In recent years, studies have shown that stifling or holding back sneezes can cause damage to the sinuses as well as to the inner ear and brain cells. This is due to the back-flow of the significant air pressure created during a sneeze, results of which could be very painful. Possible consequences include tinnitus, reduced high-frequency hearing, and in extreme cases, rupturing of the ear drum. Safer alternatives have been proposed to stifle sneezes, including methods involving prolonged deep exhalation immediately preceding a sneeze, which in turn empties the lungs, rendering the body unable to expel the necessary amount of air required for an average sternutation.