The lymphatic system runs throughout your body in parallel to your blood vessels. It comprises hundreds of lymph nodes, lymph vessels, and lymphatic capillaries spread throughout your body. The lymph vessels collect and return excess fluid from all over the body, filter and concentrate it, and then deliver it back into the blood circulation.
Lymph vessels and capillaries collect fluid from the spaces between the cells, from all over your body. Once the fluid passes into the lymphatic vessels, it is called lymph. The fluid is filtered by forcing it through lymph nodes. Lymph vessels have one-way valves that act like gates and direct the lymph fluid in one direction. Your muscles' movement, pulsation from your arteries, and breathing squeezes the lymph vessels and supports the lymph transport. Manual Lymphatic Drainage and compression therapy are external ways to support the lymph transport.
Fighting infection: The lymphatic system is part of the immune system. It produces and releases cells that are called lymphocytes, also known as white blood cells, which defend your body against bacteria or viruses amongst others.
Lipid (fat) absorption: The lymphatic system also absorbs lipids (fat) from the gut and transports them to the blood.
Maintaining the body's fluid levels: The lymphatic system collects excess fluid, including waste produced by your body's cells. It filters the fluid and transports it back to your blood system.
Damages to the lymphatic system cause a collection of the lymph fluid, and this, in turn, causes swelling in the affected area of the body, for example an arm or a leg. This swelling is called lymphedema. Lymphedema is a long-term (chronic) disease. Without treatment, lymphedema worsens over time. Long-term damages to the lymphatic system and swelling can cause thickening and scarring of your tissue. This is called fibrosis. In severe cases, the lymphatic fluid may leak through the skin, called lymphorrea.
Without treatment, lymphedema can cause further complications. Lymphedema goes ahead with a higher risk of skin and tissue infections. One example is cellulitis - a bacterial infection of the deeper layers of the skin. Inflammation of the lymph vessels, called lymphangitis, can spread to the skin and tissues. This again can cause cellulitis. When the infection spreads to the blood system it can cause a severe, generalized infection, called sepsis. Lymphedema also affects the appearance of the body which can add to the impact the condition has on the mind - especially in those who have or had to deal with cancer. All the psychological distress lymphedema can cause increases the risk for anxiety and depression.