ABSTRACT
Physiological Functions The width of the airstream through the turbinates is narrow, and-if one considers the whole cross-sectional area of each level of the respiratory system, from nose to alveolithe narrowest point is just anterior to the inferior turbinate. The nose, in fact, accounts for up to two-thirds of the total respiratory resistance. Despite the fact that nasal breathing as compared with mouth breathing doubles the resistance to breathing we prefer to breath through our noses. A small exchange of air occurs in the paranasal sinuses with each change in intranasal pressure. A number of factors affect nasal resistance, including normal cyclical variations in vascular congestion oscillating from one side of the nose to the other, posture, exercise, and cold air. In addition, pathological conditions can increase nasal resistance. This occurs in response to noxious air pollutants, aeroallergens, infectious or ganisms, and certain pharmacological agents.
