MadSci Network: Anatomy

Re: What effect does the uvula have on swallowing in humans?

Date: Tue Jun 30 11:25:00 1998
Posted By: Leslie Gartner, Faculty Histology/Anatomy, University of Maryland, Baltimore, MD
Area of science: Anatomy
ID: 895346609.An

Dear Hanna,

The uvula has a very important function in swallowing, but before 
telling you what it is let me give you a little background. 

The nasal cavity is separated from the oral cavity (mouth) by the palate. 
The front region of the palate has a bony plate (and the teeth are 
suspended in part of that bone) which makes that part of the palate firm 
and is called the "hard palate." The backward continuation of the hard 
palate has no bone, but has several muscle in it, and is called the soft 
palate. The uvula is the continuation of the soft palate and when you open 
your mouth and look in the mirror, you can see it hanging down in the 
middle of your throat. If your mouth is closed and you're inhaling through 
your nose the air enters your nostrils, goes into your nasal cavity, passes 
by your soft palate and uvula and enters the interior of your pharynx and 
then larynx (Adam's apple)on its way to the lungs. During exhalation with 
your mouth close, the air comes out of the lungs, through the interior of 
the larynx and pharynx, past the uvula and soft palate, into your nasal 
cavities and out the nostrils. 

When you are eating the following occurs: First just the idea of eating (or 
even just the smell of food) will cause saliva to enter your mouth and as 
you chew your food into smaller and smaller fragments, the saliva mixes 
with it. The food is pushed by your tongue against the hard palate, 
assisting the mouth in macerating the food. When the food is moist enough, 
soft enough, and small enough, the back of the tongue pushes it down the 
pharynx from which it enters the esophagus. In order to prevent the food 
from entering the nasal cavity, the muscles elevate the soft palate and 
uvula, closing off the opening between the nasal cavity and the pharynx. If 
it weren't for the uvula, the seal between the two cavities would not be as 
effective as it is.

This is an automatic response, so you don't have to think about elevating 
your soft palate and uvula, they do it by themselves. Occasionally, and if 
this has not happened to you I am sure that you have seen it with some of 
your friends. When you're drinking something, such as a glass of milk or 
coke, and someone cracks a joke you suddnly laugh. In order to be able to 
laugh you have to exhale, therefore, the muscles of the soft palate and 
uvula relax, they drop into the breathing position, and the milk (or the 
coke)comes spurting out of your mouth AND nostrils. 

There are some people who do not have uvulas (as the result of a birth 
defect or surgery) and they are quite capable of overcoming this 
deficiency, but they cannot form as effective a seal as people with a 

I hope this helps.

Leslie P. Gartner
Department of Anatomy, OCBS
Dental School
University of Maryland

Current Queue | Current Queue for Anatomy | Anatomy archives

Try the links in the MadSci Library for more information on Anatomy.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-1998. All rights reserved.