Editing Snoring (section)

==Mechanism==
[[File:Blausen 0872 UpperRespiratorySystem.png|thumb|right|alt=Upper respirator tract|Upper respiratory tract]]
Snoring has been [[Mathematical model|mathematically modelled]] wherein the upper airway is a tube which has an elastic or collapsible section. As the section of the upper airway narrows, [[Airway resistance|resistance to the flow of air]] increases.<ref name="Yaremchuk2020" /> There is a cyclical obstruction and reopening of the airway at the partially or fully collapsed section as air flows past.<ref name="Yap2022">{{cite journal |last1=Yap |first1=YY |title=Evaluation and Management of Snoring. |journal=Sleep Medicine Clinics |date=March 2022 |volume=17 |issue=1 |pages=25–39 |doi=10.1016/j.jsmc.2021.10.010 |pmid=35216759}}</ref> This obstruction and reopening occurs at approximately 50 times per second, which causes vibration and noise.<ref name="Yap2022" /> The airflow becomes unstable and [[Turbulence|turbulent]].<ref name="Yaremchuk2020" /> 

The structures that obstruct the airway and vibrate are various [[soft tissue]] structures at different levels along the upper respiratory tract or [[aerodigestive tract]].<ref name="DeMeyer2019" /> These are the [[uvula]], [[soft palate]], [[Fauces (throat)|faucial pillars]] ([[palatoglossal arch]], [[palatopharyngeal arch]]), [[palatine tonsil]]s, [[adenoid]] tonsil, walls of the [[pharynx]], [[epiglottis]], or lower structures.<ref name="ICSD-3" /><ref name="Yaremchuk2020" /> These structures may relax during sleep and move position, especially under the influence of gravity. This results in partial obstruction (narrowing) or complete obstruction of the airway. Partial obstruction of the airway is more associated with primary snoring, whereas complete obstruction is more a feature of obstructive sleep apnea.<ref name="Deenadayal2022" /> The following structures were found to vibrate during snoring: soft palate in 100% of cases, pharynx (53.8%), lateral pharyngeal wall (42.3%), epiglottis (42.3%), and tongue base (26.9%).<ref name="Yap2022" /> In primary snoring there may be vibration of the soft palate alone, termed "palatal fluttering". In mild to moderate obstructive sleep apnea, there may be vibration of the palate and lateral pharyngeal wall. In severe obstructive sleep apnea, there may be vibration of the tongue base and epiglottis in addition to the above structures.<ref name="Yap2022" />  
 
The snoring sound mainly occurs during inhalation (breathing in), but it may occur during exhalation (breathing out).<ref name="DeMeyer2019" /> Snorers have more negative pressure in their airway, increased inspiratory time, and limitation of respiratory flow.<ref name="Yaremchuk2020" /> On [[polysomnography]], snoring is usually louder during [[slow-wave sleep]] (stage 3 [[non-rapid eye movement sleep]]) or [[rapid eye movement sleep]].<ref name="ICSD-3" /> Snoring in obstructive sleep apnea usually occurs when airflow turbulence is maximum, which is during [[hyperpnea]] episodes at the end of [[apnea]] events (breathing cessation).<ref name="Yap2022" />