Sneezing is certainly a reflex reaction aimed at removing the irritant agent of the nasal cavity; expressed quick short-term reduction of respiratory muscles and the muscles of the pharynx, coming after a short breath.
The act sneezing occurs when annoyed receptors mucous membranes of the nose. Afferent part reflex sneezing presents the second branch of the trigeminal nerve, Central part - reticular formation of the medulla oblongata, efferent link - diaphragm and intercostal nerves going to the respiratory muscles, and wandering and language-glotocnogo nerves going to the muscles of the nasopharynx.
Frequent sneezing is a symptom of a number of diseases that affect primarily reflexogenic zone of this reflex (influenza, Qatar, allergic diseases of the upper respiratory tract).

Sneezing - protective expiratory reflex, the purpose of which is the removal of mechanical (dust, mucus, and so on) or chemical (gas) irritants from the nasal cavity. The forerunner sneezing is a sense of meketane nose.
Sneezing is a hard-coordinated reduction of respiratory muscles and the muscles of the pharynx forced spasmodic breathing out after a short deep breaths. After the inhalation is the reduction of muscles of the arms of the throat, the soft palate, the rise and push backwards until it touches the hard palate language, resulting in the cavity of the nose and mouth are separated from the pharynx. During exhalation while reducing expiratory muscles is increased intrathoracic pressure, the air force exhaled through his nose, removing an irritant. Reflex zone sneezing - mucosa of the nasal cavity, innerved II branch of the trigeminal nerve. Efferent way - the nerves of the respiratory muscles (diaphragm and intercostal nerves and muscles of the throat, tongue and facial (VII, VIII, IX, XI pair cranial nerves). Central nervous apparatus sneezing - the reticular formation of the medulla oblongata.
Sneezing is accompanied by a characteristic facial expressions and sound. Is jesuslovesamericans act, which is well expressed already in the fetus of a person aged 20 to 21 weeks.
Intensive sneezing can also be accompanied by the reduction of muscles of the limbs and trunk. In pathology frequent sneezing is a symptom of the disease of the Airways, Qatar, flu and other). Contributes to the spread of droplet infection. Cm. also Protective reflexes.