The Nose – a glorious appendage Part 2

nose hairs

I once heard about an old man who did up chairs, and took a couple around to his shed. I will never forget walking in to an immaculate space, tools hanging in tidy rows, clipboards in a line, floor clean, a line of beautifully done up chairs in one corner and some tatty ones waiting in another.

The nose is a highly efficient workshop.  Different structures in their place and a smooth function.
In Part 1 we got the air past the hairs and fragrance areas.

One of the things that I admire about the respiratory system is how the lining of each part changes to suit its function.

The air passes over 3 turbinates shown as long fingers on each side wall of the nose. These are long bony structures, the inferior one is about the size of an index finger and the middle one about the size of a small finger.
These turbinates  increase the surface area for the specialised epithelium or lining the nose depends on..            

concha histologynasal epithelium

 

The first image  (source) shows the cells surrounding the pink bone structure of a turbinate. Note the columnar eipithelial cells as per the second image, (source) are just a thin green line at the surface as there are so many goblet cells dyed green producing mucous. Between the bone and epithelium are many blood vessels and lymph vessels.  These will swell when there are allergies or irritants in the air, or with changes in temperature or infections and the nose will feel stuffy. Turbinates will return to their origonal size when the stimulant has gone.

The Function of the Turbinates  (or you may hear them called conchae)

1 -They control traffic by directing the airflow smoothly and quietly through the nose towards the throat.

2 -They increase the surface area of the nose significantly and because they have blood vessels just below the epithelium this allows the air to be quickly warmed and humiifyed to protect the ongoing respiratory airways through the chest.

3 -Turbinates also trap more than 75% of the water vapor returning from the lungs upon exhalation and thus help protect the body from dehydration.

4 -They have pressure sensing receptors, letting the brain know there is sufficient air flow for respiration.

5 -They provide most of the nasal resistance to the lungs. The lungs need some resistance to allow them to reach their proper inflation and deflation rates during inhalation and exhalation. The nose supplies 50% of the entire resistance to the lungs.

6 – They protect some openings from the tear duct to the eye and sinuses. “Whatever tears one may shed, in the end one always blows one’s nose.” Heinrich Heine
(source)

The image on the right shows how the eye ducts run down to tuck under the inferior
turbinates, and the maxillary and frontal sinuses drain below the middle turbinates.turbinates and lacrimal glands in the nose
The image below shows how the eustacian tubes from the ears drain at the back
of the nasal area beyond the turbinates, into the nasopharanx.

 

eustacian tube

 

 

 

(source)

 

 

(source)
One more function of this area, is that every time you breathe in , tiny amonts of nitric oxide from the nose and sinuses are inhaled into the lungs where it helps with killing off microbes in the air and dilating the blood vessels to help gas exchange.

I wanted to find a positive quote to finish with, from someone apart from me who accepts their nose as a fabulous organ. But I couldn’t, so decided to end nasal anatomy with an animal story from the same nose quote source as the quotes so far.