About Lymphoma > Lymphatic System

What is the 
Lymphatic System?

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"Shotty lymph nodes" refers to clusters of small swollen nodes. Shotty nodes may occur when the immune system is reacting to an infection -- it doesn't necessarily point toward any particular disease. 

"Bulky disease" generally describes a lymph node or extranodal tumor that measures greater than ten centimeters in any dimension. 

calcified nodes are not really rare, and typically are 
the result of some past, healed infection. TB is well-known to cause them, 
for example. Cancer is not." 
medhelp.orgs

Cervical lymph nodes  are lymph nodes located in and around the neck. See Image mage on WebMD Anatomy

Anatomical Regions for the Staging of Hodgkin Lymphoma
SEER
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Lymph nodes above
the diaphragm

Lymph nodes below the diaphragm

Understanding the lymphatic system can help you to understand lymphoma.

The lymphatic system consists of organs, ducts, and nodes. It transports a watery clear fluid called lymph.  This fluid distributes immune cells and other factors throughout the body. It also interacts with the blood circulatory system to drain fluid from cells and tissues. The lymphatic system contains immune cells called lymphocytes, which protect the body against antigens (viruses, bacteria, etc.) that invade the body. See more on lymphocytes below.

Main functions

Also see from this source
Anatomy of lymph system 
Role of the lymphatic system in fat absorption and transport 
The lymphatic circulation as a drainage system (illustrated) 

Lymph organs include the bone marrow, lymph nodes, spleen, and thymus. Precursor cells in the bone marrow produce lymphocytes. B-lymphocytes (B-cells) mature in the bone marrow. T-lymphocytes (T-cells) mature in the thymus gland.

Besides providing a home for lymphocytes (B-cells and T-cells), the  ducts of the lymphatic system provide transportation for proteins, fats, and other substances in a medium called lymph.

Lymph nodes: "Human lymph nodes are bean-shaped and range in size from a few millimeters to about 1-2 cm in their normal state. They may become enlarged due to a tumor or infection. White blood cells are located within honeycomb structures of the lymph nodes. Lymph nodes are enlarged when the body is infected due to enhanced production of some cells and division of activated T and B cells. In some cases they may feel enlarged due to past infections; although one may be healthy, one may still feel them residually enlarged."  Wikipedia.org 

"Lymph means clear water and it is basically the fluid and protein that has been squeezed out of the blood (i.e. blood plasma). The lymph is drained from the tissue in microscopic blind-ended vessels called lymph capillaries. 

These lymph capillaries are very permeable, and because they are not pressurized the lymph fluid can drain easily from the tissue into the lymph capillaries. 

As with the blood network the lymph vessels form a network throughout the body, unlike the blood the lymph system is a one-way street draining lymph from the tissue and returning it to the blood."  Source bbc.co.uk

"Secondary lymphatic tissues control the quality of immune responses. Differences among the various lymphatic tissues significantly affect the form of immunity and relate to how antigens (bacteria, virus, fungus, etc.) are acquired by these organs. 

- Lymph nodes are filters of lymph 

- the spleen is a filter of blood 

- mucosal associated lymphatic tissues acquire antigens by transcytosis to lymphoid tissue from the "external" environment across specialized follicle-associated epithelial cells."  Source geocities.com 

"Lymphatics are found in every part of the body except the central nervous system. The major parts of the system are the bone marrow, spleen, thymus gland, lymph nodes, and the tonsils. Other organs, including the heart, lungs, intestines, liver, and skin also contain lymphatic tissue."  gorhams.dk

Lymphocytes

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Lymphocytes, also called white blood cells, are described below.

"Lymphocytes" are small cells, 7-9 µm in diameter in blood smears ...

second most common white blood cell type, comprising about 30 % of the leukocyte population in peripheral blood....

Lymphocytes travel in the blood, but they routinely leave capillaries and wander through connective tissue. Therefore, lymphocytes may be normally encountered at any time in any location. They even enter epithelial tissue, crawling between the epithelial cells. They reenter circulation via lymphatic system channels (hence their name)." 

Source: Blood Cells  www.siumed.edu 

Life cycle of lymphocytes

Lymph Nodes

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The lymph node provides an environment where lymphocytes can receive initial exposure to foreign antigens (viruses, bacteria, fungi, etc.). This activates the lymphocytes to perform immune functions. Most lymph nodes form in clusters throughout the system, such as in the neck, armpit, and groin.

 Other Elements in Lymphatic System

Click to enlarge spleen illustration
  Merck Manual

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The spleen is another important lymphatic organ. It processes lymphocytes from incoming blood. The tonsils and adenoids are secondary lymphatic organs. 

The spleen is a spongy, soft organ about as big as a person's fist, is located in the upper left part of the abdomen, just under the rib cage.  merk.com

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