|MadSci Network: Anatomy|
Dear Mrs. McClure,
As you probably know the lymph nodes are a part of network of vessels which filter foreign particles and interstitial fluid. The lymph nodes specific function is to filter fluid as the fluid returns from the periphery of the body back to major collecting ducts. The lymph nodes are filled with immunologic cells which help us fight off infection. They are often spoken about with cancers because metastasized cells are often found within them. They can help prevent cancers through immunological attack; however, they are often also responsible for spreading cancerous cells as the lymph fluid is returned back to collecting ducts such as the thoracic duct.
Now I will try to get back to your question. Your lymph nodes are typically located at branches of these lymphatic vessels. These vessels occur throughout your body just as your blood vessels do. This leaves a lot of branches for lymphatic vessels. I consulted one pathologist who does not believe that anyone has actually counted the number of lymph nodes. Lymph nodes are difficult to count because they are not typically noticed unless they are inflammed. Including lymph nodules, which are unencapsulated lymph nodes, there are probably on the order of manitude of tens of thousands. Perhaps even a hundred thousand lymph nodes distributed throughout the body.
There are several places in the body where lymph nodes are strategically located for immunological purposes. These include areas such as the neck, groin, axillae, mediastinum, and abdominal cavities because antigens, or foreign pathogens, are commonly encountered in these places. We are probably most familiar with the lymph nodes located in our neck area. These lymph nodes commonly swell up and are detectable by touch when we have a sore throat. You can feel them under chin as two tender lumps on your neck just below you jaw bone. Or perhaps you have had your tonsils removed these too are lymph nodes.
The immune system and its network of vessels, organs, and cells are a very interesting subject with a lot left to be understood. If you would like further information I would suggest checking out an anatomy or immunology text. There are also a few websites which may be helpful. I hope that answer is satisfactory. If you need anything else feel free to email me.
Try the links in the MadSci Library for more information on Anatomy.