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dominance. However, most of the modern studies have not been able to provide a conclusive statement on the cyclic pattern of nasal dominance, except that the nasal cycle is indeed present as an ongoing physiological phenomenon and may represent the fundamental biorhythms present in individuals. In any case, the phenomenon can be readily verified by personal observation.
The sympathetic nerves control nasal congestion whereas parasympathetic nerves control nasal secretion with some associated influence on blood flow and congestion. Reduced nasal sympathetic vasoconstrictor tone causes congestion, whereas increased sympathetic activity causes decongestion. Reduced parasympathetic tone causes reduced nasal secretion and reduced congestion, whereas increased parasympathetic tone causes increased nasal secretion and increased congestion.
It has been stated by some researchers that the resistance to air flow in nasal breathing may be an efficient passive means of slowing air flow to provide adequate gas exchange at low ventilation rates. It has been observed that underlying the mucous membrane in the nose there is a spongy substance called erectile tissue which fills with blood in much the same way as our sexual organs. There is a condition during sexual arousal called 'honeymoon nose' characterized by chronically clogged nasal passages. The expansion and contraction of this erectile tissue in the nostrils alternates the flow of breath between the left and right sides. The congestion enhances humidifying and warming of inhaled air and may therefore be an efficient passive mechanism for braking the respiratory system elasticity during periods of low ventilation.
Factors affecting nasal dominance There are a number of factors which alter congestion in one nasal cavity. The first is posture. When lying on one side, the lowermost, or dependent, nostril congests while the uppermost nostril opens. However, if there is no support underneath the axilla (armpit), nasal congestion does not change. On the other hand, pressure under one axilla in the form of a crutch will
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