Lymph nodes are small organs which are distributed all across the body. There are filtering units which filter the foreign substances in the lymph fluid which flows from tissues to tissues collecting all the waste products and toxins. The Lymph Nodes are nearly 1cm to 2cm long and 500 to 700 of them are present in our body. Some of them get swollen and bigger, sometimes.

The germs gathered by the lymph vessels can be attacked and detsroyed by the Lymph Nodes that contain immune cells. The fluids and substances that are picked up by the lymph vessels are filtered by the node. The Lymph Nodes are located in clusters at specific sites. For example, the Lymph Node at the elbow or at the armpits filter the lymph channels from the hand, palm, and fingers. At the nodes behind the knees or at the groin is where the lymph channels from the legs, feet and toes drain. The Lymph Nodes in the neck filter the channels from the face, head and scalp. Also, there are deeper Lymph Nodes that are located between the lungs, around the coils of the intestines etc.

Lymphocytes are a type of white blood cell, which are held by the Lymph Nodes. Lymphocytes fight against foreign invasion by cancer cells, toxins, bacteria or viruses. The immune responses are controlled by Lymphocytes. This function takes place when lymphocytes get in contact with foreign materials – generally toxins called antigens or protein on the germs. Once in contact with the antigens the lymphocytes are activated. The stem cells in the bone marrow is where these lymphocytes originate from.

Lymphocytes can be divided into two major categories – B cells and T cells. Complete development of B cells takes place in the bone marrow while the T cells are discarded from the bone marrow when they reach other organs like the thymus where they gain maturity to combat foreign antigens and infections.

The major function of the Lymph Nodes is to filter the waste matter from the lymph fluid. It clears the bacteria, viruses and other toxins from the lymph fluid and destroys them.

The swollen Lymph Nodes are the result of infections. Whenever there is an infection, the Lymph Nodes of that location get swollen and the size depends on the location of the infection and its intensity. The swell is because of the collection of the infecting organisms by the Lymph Nodes to destroy

Some of the major Lymph Nodes of our body are cervical Lymph Nodes of the neck, axillary Lymph Nodes of armpits, supraclavicular Lymph Nodes along the collar bone, mesentery Lymph Nodes in the lower body below the rib cage and mediastinal Lymph Nodes in the upper body between the lung sacs.

The major Lymph Node disorder is the excessive swelling of the Lymph Nodes and it is known as lymphadenopathy. This disorder is mainly due to the blockage of the lymph vessels because of infections or cancer and when the Lymph Nodes are unable to destroy the foreign particles.

There are two ways through which cancer can appear in the Lymph Nodes – it can either begin from there or spread there from somewhere else. Lymphoma is the cancer that starts from the Lymph Node. Often, cancer starts from some other part in the body and eventually spreads into the Lymph Nodes. As soon as cancer cells break away from a tumour, they can travel to other parts of the body either through the bloodstream or through the lymph system. Through the bloodstream, cancer cells can travel to reach distant organs. However, if the cancer cells travel through lymph system, they may end up in Lymph Nodes. When cancer grows inside the Lymph Nodes, it generally affects the Lymph Nodes near the tumour itself. And these nodes are the ones that are responsible for doing most of the work of filtering out or killing the cancer cells.