How the Lymphatic System Works

The lymphatic system (also called the lymphoid system) is part of the immune system. The system moves lymph, a clear fluid containing white blood cells, through your bloodstream. 

The lymphatic system involves many organs, including the tonsils, adenoids, spleen, and thymus. Lymph nodes filter out bacteria and cancer cells and create white blood cells to fight infection. These nodes are found throughout the body (neck, armpits, groin, chest, and abdomen).

This article explains the function of the lymphatic system, lymphatic diseases, and how to improve lymphatic health. 

Healthcare provider examining the neck of an older adult.
Jose Luis Pelaez Inc/MNPhotoStudios / Getty Images

How Does the Lymphatic System Work?

The lymphatic system includes tissues, vessels, and organs that move fluid throughout the body and fight infection. When excess plasma (the liquid portion of blood) collects in your body’s tissues, the lymphatic system collects it and moves it back into your bloodstream.

Plasma

Plasma is the liquid component of blood. It makes up 55% of your blood. Red and white blood cells and platelets, suspended in the plasma, make up the remaining portion.

Fighting Infection Starts With Lymph

Lymph is made up of more than plasma. The excess fluid that drains from your cells and tissues is made of many substances, including:

From Your Tissues to Your Lymph Nodes

Lymphatic vessels are tiny blood vessels and tubes that move lymph from tissues to lymph nodes, which filter out damaged and cancer-causing cells. In addition, the lymph nodes create immune cells to fight infection and other harmful substances it detects in the fluid.

You have about 600 lymph nodes in your body. Lymphatic vessels connect this network of lymph nodes.

Through Lymphatic Vessels to Collecting Ducts

Once the lymph passes through the lymph nodes, it continues through the lymphatic vessels until it reaches the collecting ducts. There, it empties before returning the filtered lymph to your bloodstream.

Lymphatic System Organs

In addition to lymph, lymphatic vessels, lymph nodes, and collecting ducts, many organs are involved in the lymphatic system. Primary lymphatic organs produce immune cells called lymphocytes, while secondary lymphatic organs fight off germs and harmful substances. 

Primary lymphatic organs include:

  • Bone marrow: This sponge-like tissue is located inside your bones. Here, immune cells grow and multiply. 
  • Thymus: This gland is located behind the breastbone. Immune cells, called T-cells, mature in the thymus. 

Secondary lymphatic organs include:

  • Spleen: This organ sits in the left upper corner of the abdomen. The spleen stores immune cells and platelets and break down red blood cells.
  • Tonsils: These are located in the throat. They stop germs from entering the body through the mouth and nose. They also use white blood cells to fight infection.
  • Lymph nodes: These bean-shaped glands are located throughout the body, including the armpits, groin, and neck. They filter lymph and create antibodies.
  • Mucous membranes: These are located through your respiratory and digestive systems. The membranes in your bowel wall, appendix, respiratory and urinary tracts, and vagina fight off foreign substances and infections.

Lymphatic Diseases

When the lymphatic system malfunctions, some diseases or disorders can occur. These complications can range from infections to blockages to cancer.

Blockage

A blockage in the lymphatic system often leads to fluid buildup. In addition, blockages can result from scar tissue from surgery, injury, or infection. Examples of disorders associated with blockage include:

  • Lymphedema: This is an accumulation of lymph fluid in the body. It most commonly occurs in the arms and legs. It ranges from mild to very painful. It is common in people who have received cancer treatment.
  • Lymphatic filariasis: Also called elephantiasis, this infection is caused by a parasite that infects the body through a mosquito bite. The worms invade the lymphatic system, resulting in a blocked lymphatic system and swelling, pain, and disfigurement. 

Inflammation and Infection

Infection and inflammation can lead to problems with the lymphatic system. These include:

  • Lymphadenopathy: This is the medical term for swollen lymph nodes. Lymph nodes, themselves, can become infected, but swollen lymph nodes also indicate an infection within the body. Some infections that commonly result in enlarged lymph nodes include mononucleosis, strep throat, HIV, and skin infections. Lymphoma (cancer of the lymph nodes) and leukemia may also be associated with lymphadenopathy.
  • Lymphadenitis: This term refers to an infection of the lymph node(s). This infection often occurs due to germs that spread through the lymphatic system from one part of the body to the lymph nodes.
  • Lymphangitis: Inflammation of the lymph vessels, which may result from some bacterial infections.
  • Lymphocytosis: This condition is a higher than normal amount of lymphocytes, often a result of your body dealing with infection or inflammation. 
  • Castleman disease: This condition is an overgrowth of cells in the lymphatic system. An infection causes it. It may result in a full feeling in the abdomen, lumps in the armpits, groin, neck, and weight loss.
  • Mesenteric lymphadenitis: This is inflammation of lymph nodes in the abdomen. An infection causes it, and it usually affects children and teenagers. 
  • Tonsillitis: An infection of the tonsils, resulting in a very sore throat. 

Congenital or Genetic Conditions

Sometimes malfunctions of the lymphatic system occur when you are born. These conditions include:

  • Intestinal lymphangiectasia: This occurs when there is a loss of lymph tissue in the intestines. Most often, children are diagnosed before age 3.
  • Lymphangioma: This is a malformation in the vascular lymphatic system. 
  • Lymphangioleiomyomatosis: This is a rare lung disease where cells grow out of control in the lymph nodes, lungs, and kidneys. 
  • Autoimmune lymphoproliferative syndrome: This genetic disorder of the lymph nodes, liver, and spleen results in high lymphocytes.

Cancer

Cancer of the lymphatic system is called lymphoma. It occurs when lymphocytes multiply in the body uncontrollably. There are two categories of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma

Non-Hodgkin lymphoma is one of the most common cancers in the U.S. It makes up about 4% of all cancers.

Lymphatic System and General Health

The lymphatic system directly impacts other systems of the body. These include:

  • Circulatory system: This system, also known as the cardiovascular system, comprises the lymphatic system. These systems work together to move blood and lymph throughout the body. However, unlike blood circulation, the lymphatic system moves a combination of cells, minerals, nutrients, and waste through the vessels.
  • Immune system: The lymphatic system is a part of the immune system. The immune system’s role is to protect the body from disease and other harmful substances. It is continually working to build up a defense against germs. As a part of the immune system, the lymphatic system plays an important role. As it moves lymph throughout your body, it identifies, filters out, and reacts to foreign substances by creating antibodies.

Caring for Your Lymphatic System

Your exposure to certain things can impact the lymphatic system. Therefore, there are some ways that you can support a healthy lymphatic system, including:

  • Avoiding chemicals like pesticides and harsh cleaning products
  • Staying properly hydrated
  • Eating nourishing foods
  • Getting adequate physical exercise

When to See a Healthcare Provider

If you notice unusual swelling or extreme fatigue, it's a good idea to contact your healthcare provider to have them evaluate your situation.

Summary

The lymphatic system is part of the immune and circulatory systems. It is responsible for moving excess fluid, called lymph, out of tissues and back through the body. During this process, the lymph travels through the lymphatic vessels, lymph nodes, and collecting ducts before cycling back through the body.

A Word From Verywell

If you have a lymphatic disorder, you may be feeling overwhelmed or confused. That's understandable; the lymphatic system is a complex network that can take some time to understand. Rest assured that lymphatic conditions are often manageable. In addition, there are things you can do to ensure your system functions optimally. Drinking lots of water, eating nourishing food, and getting enough movement can help your lymphatic system flow as it should. Talk to your healthcare provider if you notice signs that your lymphatic system is not functioning optimally.

Frequently Asked Questions

  • What are the main lymphatic system organs?

    The organs of the lymphatic system include bone marrow, thymus, spleen, tonsils, lymph nodes, and mucous membranes.

  • What is a lymphatic system detox?

    A lymphatic system "detox" involves doing certain things to help your lymphatic system drain more effectively. However, there is not a lot of evidence to support the practice. Some simple, healthy things to try include staying well-hydrated, eating nourishing food, and getting adequate exercise.

  • How do you know if your lymphatic system is blocked?

    If your lymphatic system is blocked, the fluid buildup may result in swelling in your soft tissues. Often this occurs in the arms and legs. It most often occurs in people who have undergone cancer treatment.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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