Scientists have recently discovered a new set of salivary glands. Until now, everyone thought we had three sets of large ones: one near the ears, another below the jaw, and another under the tongue. (There are also a bunch of small ones in your mouth.) The newly-discovered fourth pair sits where the nasal cavity meets the throat, draped over the tubes that connect the ears to the throat.
A typical adult secretes a little less than a quart and a
half of saliva a day. Saliva is almost entirely
water, but a tiny portion is full of useful enzymes that speed up chemical
reactions in your mouth, such as breaking down sugars in carbohydrates. Other
enzymes attack pathogens.
At the moment, the new discovery is of most importance to oncologists
who use radiation therapy for patients with cancer of the head or neck. Because
doctors didn’t know the glands existed, nobody tried to spare them from such
treatments. Patients often end up with chronic dry mouth and swallowing
problems. Besides radiation treatments, hundreds of medications produce dry
mouth, including those used to treat depression, high blood pressure and
anxiety, as well as some antihistamines, decongestants, muscle relaxants, and
pain medications.
I know from experience that fear also makes your mouth dry. This
happened to me when it was my turn to give my first speech at Toastmasters. Fear
engenders a fight or flight response, slowing down all the body processes that
aren’t necessary for your immediate survival, including your digestive system
of which salivary glands are a part. Considering that many people fear speaking
in public more than they fear death, the fight or flight response isn’t
surprising. For my part, I think dying is worse than speaking in public.
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