The lymphatic system

The lymphatic system is a network of tissues, vessels and organs that work together to move a colorless, watery fluid called lymph back into your circulatory system (your bloodstream).

Your lymphatic system, part of your immune system, has many functions. They include protecting your body from illness-causing invaders, maintaining body fluid levels, absorbing digestive tract fats and removing cellular waste. Blockages, diseases or infections can affect your lymphatic system’s function.

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

Lymphatic system main functions

• Maintains fluid levels in your body: As just described, the lymphatic system collects excess fluid that drains from cells and tissue throughout your body and returns it to your bloodstream, which is then recirculated through your body.
• Absorbs fats from the digestive tract: Lymph includes fluids from your intestines that contain fats and proteins and transports it back to your bloodstream.
• Protects your body against foreign invaders: The lymphatic system is part of the immune system. It produces and releases lymphocytes (white blood cells) and other immune cells that monitor and then destroy the foreign invaders — such as bacteria, viruses, parasites and fungi — that may enter your body.
• Transports and removes waste products and abnormal cells from the lymph.