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What is the Lymphatic System?


The lymphatic system comprises tissues, organs, and a one-way system of vessels that work together to filter excess tissue fluid, bacteria, proteins, and cellular waste products from the lymphatic vessels into your bloodstream.

Each day, about 20 litres of plasma flow through your arteries, and arteriole blood vessels, and capillaries. After delivering nutrients to your body’s cells and tissues and receiving their waste products, about 17 litres are returned to the circulation through your veins. The remaining three liters seep through the capillaries and into your tissues. The lymphatic system collects this excess fluid (now called lymph) from tissues in your body and moves it along until returned to your bloodstream.

Illustration of the lymphatic and circulatory systems
Diagram of  a woman's Lymphatic system

Important Functions of Your Lymphatic System

Your lymphatic system is a part of your immune system and has several functions. You might already know, for example, that the lymphatic system plays a major role in protecting you from illnesses and infections. It produces and releases lymphocytes (white blood cells) and other immune cells that monitor and try to destroy any foreign illness-causing invaders such as bacteria, viruses and parasites.


The lymphatic system maintains body-fluid levels by draining excess fluid and protein from tissues and returning them into the bloodstream, as explained above. The lymphatic system also absorbs fats from the digestive tract and returns them to the bloodstream as well as transporting and removing waste and abnormal cells.

Infections, diseases, abnormal cells and blockages can impact your lymphatic system.

For example, when the lymphatic system becomes damaged or blocked, lymphatic fluid builds up in the tissue and causes that area to become swollen and enlarged. The area is likely to feel heavy and/or painful. If untreated, this could lead to a long-term chronic condition called lymphoedema and could increase your risk of serious infection.

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