Organs of the Immune System: Lymph Nodes

Among the organs that contribute to our immune response, there are two categories: primary lymphoid organs and secondary lymphoid organs.

Lymph nodes are considered secondary lymphoid organs, along with the spleen. Shaped like beans, they contain lymphocytes, macrophages and dendritic cells. Lymphocytes carrying antigen drain through the lymph nodes, leaving the antigen behind to be dealt with in the node.

Popular thinking very strongly associates lymph nodes with lymphoma, chiefly because one of the first symptoms of lymphoma is an enlarged lymph node, but this is a little misleading. A lymphocyte within the node can become cancerous, or a cancerous lymphocyte can arrive at the node from elsewhere in the body and remain there. But it is not necessary to have lymph node involvement in order to have lymphoma.

The Job of the Lymph Nodes

Lymph nodes cluster together at junctions of the lymphatic vessels of the lymph system. They filter harmful substances and other debris from the body that are collected from the tissues of the body outside of the bloodstream.

The lymphocytes, macrophages and dendritic cells in lymph nodes act as immune cells to kill the harmful substances brought there by the lymph vessels. Because lymph vessels run throughout the entire body, they drain back through lymph node clusters no matter where they are. The fluid in the vessels comes from the fingers and toes and goes all the way up to the scalp. This massive circulatory system is constantly working to clear these substances from the body's tissues before re-circulating again, always stopping at the lymph nodes to deposit what it collects so that the nodes can eliminate them from the body.

Familiar Lymph Node Clusters

Places where lymph nodes can be felt with one's fingers include:

  • Armpit
  • Groin
  • Under the jaw/chin
  • Behind the ears
  • Back of the head
  • Front, back and sides of the neck

Lymph Nodes in Lymphoma

Other cancers often involve the lymph nodes (when cells from tumors break away and reach the lymph nodes), but when cancers involve the B-cell lymphocytes or the T-cell lymphocytes, they are classified as lymphomas.

Lymph Node Removal

In order for a case of lymphoma to be diagnosed, a lymph node must be excised in a biopsy. This generally requires the removal of a single node. Since our bodies have several hundred lymph nodes, the loss of a single node isn't going to cause a problem.

However, when many nodes from the same cluster are removed, called either "dissection" or "lymph node sampling," this can create a big problem because lymph vessels arriving there no longer have a place to drain. Fluid back-up can occur, leading to what's called lymphedema.

More Articles

More Articles

In non-Hodgkin's lymphoma, you have your B-cell lymphomas and you have your T-cell lymphomas.

Why B...

MALT lymphoma is a rare B-cell non-Hodgkin's lymphoma that typically runs an indolent or slow-growing clinical...

Mantle cell lymphoma (MCL) is a relatively rare B-cell subtype of non-Hodgkin'...

Mantle cell lymphoma (MCL) is just one of 50-60 known B-cell subtypes of...

Lymphomatous meningitis [LM], also known as leukemic meningitis, is an extremely serious peripheral cancer that attacks the tissue that covers the...

Since so many chemotherapy agents can affect a patient’s sex drive and fertility, thinking about these issues prior...

Secondary cancers are cancers that develop as a result of chemotherapy and/or...

One of the greatest fears of lymphoma survivors is that they’ll relapse and have to undergo treatment again. This fear is normal but awful to...

Over the years, various classification systems have been used to differentiate lymphoma types including the Rappaport Classification (used until...

If you are new to this website or are looking for guidance to a specific page, here is a list of links to articles that can help you. The "Main...

Often the one who makes the first diagnosis of Hodgkin's Lymphoma / Disease is the person affected. There are some...

Lymphedema is abnormal swelling due to the presence of excess lymphatic fluid within the tissues. This swelling occurs when the...

There are two types of cancer: benign and malignant. Benign cancers are the kind that don't spread and don't threaten one's life. Malignant...

Advances in the treatment of Hodgkin's lymphoma have resulted in remarkable survival rates, even for...