Lymphatic System

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The lymph system is part of the immune system, which helps fight infections and some other diseases. The lymph system also helps control the flow of fluids in the body.

Lymphatic structures, organs, and tissues include the:

  • Lymph nodes
  • Lymph vessels
  • Spleen
  • Thymus

Lymph nodes are bean-sized collections of lymphocytes and other immune system cells. They're found throughout the body, including inside the chest, abdomen (belly), and pelvis.

Lymph vessels are a network of tiny tubes (a lot like blood vessels) that connect lymph nodes and carry immune cells in a clear fluid called lymph. Lymph is collected from around the body and put into the bloodstream.

The spleen is an organ that's under the lower ribs on your left side. The spleen is part of your immune system.

The thymus is a small organ behind the upper part of the breastbone and in front of the heart.

Written by

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Last Revised: December 13, 2022

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