The lymph nodes are small, cellular structures found almost all over the body. There are between 600-700 lymph nodes in the entire body. The lymph nodes belong to the lymphatic system in the human body. The lymphatic system's role is to get rid of any toxins and waste products that may accumulate. The lymphatic system has lymph fluid that travels around the body and is connected to lymph nodes where the bacteria and other waste products are filtered out of the lymph fluid. Lymph nodes containinfection-fighting elements. Commonly-known examples of lymph nodes in the body are the spleen, tonsils and adenoids.

Function of Lymph Nodes

An individual lymph node resembles a bean and is encapsulated by connective tissue. On the inside, there are various sections called nodules. It is here that the lymphocytes are stored. Other components of the immune system, like macrophages, are stored in the medulla, which are at the center of the lymph node. Lymphatic vessels enter and leave the lymph gland carrying lymph fluid.

• These highly specialized glands are responsible for filtering and removing any unwanted constituents in the lymph fluid. Lymph fluid is a clear and colorless liquid derived from the blood plasma.
• The lymph fluid can be thought of as a garbage truck-it collects undesirable entities from all over the body. This fluid plays an important role in the function of lymph nodes, and is then directed towards the closest lymph node for processing and filtering.
• The lymph nodes have an army of lymphocytes that attack any infection that may be contained in the lymph fluid. The lymphocytes are a very important part of the body's immune system. The lymphocytes originate from the stem cells of the bone marrow. Stem cells have the DNA blueprint to form into any specialized cells as required by the body.
• If an antigen (a foreign body, like a virus or bacteria) is discovered, these lymphocytes can produce antibodies which are very specific to the antigen detected. The presence of the antibodies signals the rest of the immune system to destroy the antigen.
• Apart from removing viruses and bacteria, the function of lymph nodes also includes eliminating other waste products like: dead cells, waste products from cells and even cancer cells.
•  "Purified" lymph fluid finds its way back into the bloodstream to prevent swelling in the body around various tissues. A microscopic network of vessels is responsible for draining the interstitial fluid away.

Diseases of the Lymphatic System

1. Lymphadenopathy

It occurs when the lymph nodes become enlarged.

• The nodes become enlarged when an antigen is recognized and the nodes begin to produce more lymphocytes to fight the infection. Once the infection is over, the glands should revert back to their normal size. Most of us have experienced the pain and enlargement of tonsillitis, a common ailment.
• Usual areas where a swollen lymph node may be detected are the groin, neck and underarms. Other nodes may be too deep to be felt by touch and can only be detected with a scan like a CT scan or an MRI.
• Swelling of the lymph nodes usually occurs in response to an infection, like a bacterial skin infection, common strep throat or a viral attack on the body.
• An autoimmune condition, like lupus, may also cause lymphadenopathy. The body's immune system recognizes its own cells as foreign antigens and starts an attack on these cells.
• The general rule of thumb is: if the enlargement occurs rapidly and is quite painful, the cause is most likely a bacteria or virus. A gradual and often painless swelling is often more serious and medical advice should be sought.
• Mumps, a previously common childhood disease, causes glands in the neck and inside the jaw to enlarge. Scarlet fever has symptoms of swollen glands and a skin rash.

2. Lymphedema

It is a lymph node blockage can lead to swelling.

• This can be a result of surgery or cancer treatment that causes an impaired function of lymph nodes flowing, resulting in swelling. This is common in women who have had a mastectomy (surgical removal of breast tissue) in response to a positive breast cancer diagnosis. This type of surgery usually involves the removal of lymph nodes found in the armpit. The result is persistent pain and swelling in the corresponding arm. Recent advances now make it possible to remove fewer lymph nodes with less of the pain and discomfort. There are also specialist lymph massage therapists that can help minimize the swelling.
• Inflammatory diseases, like Castleman disease, can also result in lymphedema. The disease may involve one or more lymph nodes and may also affect other organs in the body as well.
• A genetic medical condition, like lymphangiomatosis, may result in lesions growing onto the lymph nodes.

3. Cancers of the Lymphatic System

In this case the lymphocytes replicate uncontrollably.

• There are a few types of lymphoma that can occur. The most common type is the non-Hodgkin lymphoma (NHL). This type of may be further subdivided into follicular (about 30% of all NHL cases), diffuse large B-cell lymphoma (40%-50% incidence of NHL patients), Burkitt's lymphoma which comprises of about 5% of NHL cases and the remainder are undetermined. The Hodgkin type of lymphoma most often occurs in patients between the ages of 20 and 40 years old.
• Each cancer segment has its own unique treatment approach, depending on the individual patient case.
• Cancer cells are often spread from one part of the body to the next via the lymph fluid.