|MadSci Network: Anatomy|
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 uvula. I hope this helps. Leslie P. Gartner Department of Anatomy, OCBS Dental School University of Maryland
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