Thursday, December 31, 2009

Sneeze Reflex


The sneeze reflex is very much like the cough reflex,
except that it applies to the nasal passageways instead
of the lower respiratory passages. The initiating stimulus
of the sneeze reflex is irritation in the nasal passageways;
the afferent impulses pass in the fifth cranial
nerve to the medulla, where the reflex is triggered. A
series of reactions similar to those for the cough reflex
takes place; however, the uvula is depressed, so that
large amounts of air pass rapidly through the nose, thus
helping to clear the nasal passages of foreign matter.

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