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Nasal and Sinus Functions

The nasal passages with all their elements (Turbinates & Sinuses) function in concert to improve our breathing as compared to breathing through our mouths. This is because they:

  • Filter & cleanse the air by trapping inhaled
  • Sense of smell fibers (stippled white & yellow)
  • reside on the middle & superior turbinate
  • (st and mt)
  • (click on image to view enlargement) particles in mucus which we swallow
  • Moisturize the air in dry climates so we do not have a dry throat
  • Warm or cool the inhaled air so that we are more comfortable with it in our “wind pipe” (trachea)
  • Protect from infection via the production of immunoglobulins and toxic chemicals which diminish the frequency of infection from inhaled bacteria, molds and viruses.
    • Enable sense of smell
    • Enjoy the flowers in life
    • Enhance taste
  • Detect danger – smoke, chemical, spoiled food
  • Detect irritants and expel them via a sneeze reflex
  • Improve the functioning of our lungs at rest.
    • Interestingly, even though the nasal passages are much narrower than our mouths most of us find it more comfortable to breath through our nose in part because its narrowness helps our lungs inflate better when we are not exercising. Unfortunately, if the nasal passages are too narrow we sense the uncomfortable feeling of nasal blockage/stuffiness.

In addition to their mucus producing function, the paranasal sinuses appear to serve additional benefit: They are thought to help us by:

  • Acting as a cushion in trauma to protect the brain and eyes.
  • Improving the resonance of our voice
  • Lightening the weight of the head, so that in evolutionary terms humans could stand upright/erect.

“The Mucociliary Blanket”

Each of the turbinates and sinuses are also covered by mucosa (see Nasal & Sinus Anatomy). The mucosa of the nasal passages and sinuses produces between ½ quart and up to 1 ½ quarts of mucus /day. It is drained from the sinuses by tiny hair-like structures called cilia that beat the mucus out of the sinuses into the nasal passages and down into our throat where is usually imperceptibly swallowed. This “mucociliary blanket” serves to filter our air of tiny particles which can contain infection and other irritants which are then digested by acid in our stomach. The mucus contains defensive proteins that help protect us from invasion by organisms. Additionally the moisture of the “mucus blanket” helps humidify the air that we breathe. This “mucus blanket” becomes noticeable when there is a lot of it (thin and watery) or when it becomes thick and dry. This is typically referred to as post-nasal drip.

In addition to the mucus producing role of the mucosa, it is rich with blood vessels and nerve endings that serve many purposes that include our sense of smell and “sneeze reflex”.