How many people do you know who are infatuated with the nose? Add me to your list.
Why do we have this large external nozzle on our face? Does it serve breathing? Not specifically. Chimps and gorillas have a flat nose and they breath just fine.
I suppose some of my theology friends (of which I have many) would claim that we have an external nose to be in accord with being in the image of God. Fine, but such a claim is not an explanation as much as it is an expectation.
It ends up that the human nose may have an important "medical" function that goes well beyond the mere delivery of oxygen to the lungs. The design of our nose has to do with speech. It evolved in conjunction with several other anatomical modifications of the throat.
The human throat has a rather unique design. The larynx (the sound box) is deeper in our throats than that found in other primates. This depth allows for the air and food pathways to crossover, creating the possibility of choking. Because the larynx is low in the throat, humans have an extra space above the larynx and behind the tongue called the oropharynx, a space that is not found in other primates. The oropharynx is long and narrow, functioning as a resonance chamber for sound. Make the nasal /n/ sound and you will be able to feel the vibrations of this chamber at the back of your throat behind the tongue.
One of the problems created by this narrow oropharyngeal chamber is that the tongue can drop back during sleep and close off the flow of air, causing apnea (loss of breathing).
H. D. Stupak (2010; Otolaryngology – Head & Neck Surgery, 142, 779-782), in a brilliant paper, argues that the external nose causes a highly curved airflow pattern that results in the inflation of the soft palate and the tongue, preventing blockage of breathing. In fact, a widely used treatment for apnea is just an exaggerated version of the natural curved airflow – something called "continuous positive airflow pressure." Apnea patients often wear a gasmask at night in order to obtain the extra air pressure that is needed to keep the tongue in a forward position.
Thus, our nose should be seen as an airflow direction nozzle that appears to be designed to keep us breathing during sleep. Most of the time it works, fortunately.
Sometimes my theology friends claim to me that evolutionary science has no medical value.
Setting aside the volumes of information on evolutionary medicine that is in the literature, let me humbly suggest that our treatment for obstructive sleep apnea would be highly impaired if we did not have some evolutionary understanding of that unique airflow feature on our face called the external nose.
As my LDS cousin says, who is an E.N.T. physician, "It's not the size of the nose that matters; it's what's inside that really counts!" I suppose that is an inside professional joke.
Anatomical jokes aside, I would claim: No nose knows what I eye. Aye???
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7 comments:
Oh, the nose is great.
"Sometimes my theology friends claim to me that evolutionary science has no medical value."
!?!? WHAT !!?!?
I guess I will try to remember that when doctors tell me there is a *new strain* of a certain disease going around.
Joseph:
Great link. Thanks. My nose knowledge has expanded.
SFaux,
I remember learning in biology about the larynx drop. The larynx drop is the larynx settling deeper into the throat during early childhood. It is important in developing speech. This drop accounts for, as you point out, the larynx being lower in the throat.
When the larynx is higher in the throat at birth, it allows babes to drink with their heads down, something adults should never attempt because we choke.
Now here is the big question. If intelligent primates had a larynx drop like humans, would they be able to enunciate basic sounds and words? Perhaps given that gorillas have been taught to communicate with sign language.
Another question: why can a parrot enunciate some basic sounds and words so well? From what I understand, this is still a bit of a mystery.
One more mystery I thought of (just fun stuff, really).
At the Kirkland temple dedication some babes in the audience were singing the hymns. If they had not gone through the larynx drop, and I assume they had not, how could this have happened? (Well, anything is possible with the Lord, but it is fun to speculate.) It most certainly had something to do with the veil being removed and their adult spirits coming to the level of conscious awareness of what was happening at that time.
Dave C:
Thanks for your comments. No, I don't think a low larynx is enough for speech. It needs to be accompanied with a narrow oropharynx to serve as a resonance column. Also, the structure of the nasal cavity is important. There are a number of issues: even neural control of breathing needs to be altered.
I had not heard of the claim that babies sang at the dedication of the Kirtland temple. I believe that dedication was extraordinary, but I cannot swallow all the stories associated with it. Mormons like to exaggerate just as much as everyone else. But, I do not want to push that point too hard, because Mormon culture surprises more more often than not.
Thanks for reading and reacting.
I love the blog! I am your newest follower. Im LDS as well. Im on here at www.konradjuengling.blogspot.com . :D
Konrad:
You are very much welcome here!! Please return.
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