What is the lymphatic system and what does it do?

The lymphatic system is made up of thin tubes, known as lymphatic vessels, that run throughout the body. It forms part of the immune system and helps to protect against infection and disease.

The system is comprised of lymph nodes and several organs including the tonsils and spleen. Both the tonsils and the spleen are involved in the production of lymphocytes (white blood cells).

  • What is lymph fluid?

Lymph fluid is the colourless liquid that travels through the lymphatic system to carry cells that fight infection. It also plays a part in removing toxins and waste products out of the body.

  • What are lymph nodes?

Also known as lymph glands, there are approximately 600-700 lymph nodes found throughout the average adult body. Nodes can be as small as a pinhead and as big as a baked bean. Nodes are found in larger numbers in the armpits, groin, neck, abdomen, pelvis and chest.

Lymph nodes contain white blood cells (lymphocytes) and are able to target and break down dangerous cells such as bacteria, viruses, cancer cells and damaged cells. Lymph nodes can sometimes be felt underneath the skin. They may appear swollen when they are fighting an infection.

The nodes filter the lymph fluid before it is returned to the circulatory system.

  • What are lymph vessels?

Lymph vessels are the thin tubes that transport the lymph fluid through the body via nodes, and towards either the thoracic duct or right lymphatic duct found in the base of the neck. It is at this point that the lymph fluid (or ‘lymph’) is emptied back into the blood circulation.

Lymph only travels in one direction and vessels have valves to prevent a backflow.

What conditions can develop from problems with the lymphatic system?

  • Lymphadenopathy

Lymphadenopathy refers to the swelling of non-adjacent lymph nodes. The condition can occur when the body is fighting an infection but it is important to rule out any other serious causes. Management of the condition will depend on the root cause.

  • Lymphoedema

This chronic condition refers to the build up of lymph fluid that causes swelling in the body’s tissue. It is most commonly seen in the arms and legs but can occur elsewhere.

Lymphoedema occurs when the lymphatic system is not able to work as it should. The condition can be caused by faulty genes or due to damage to the lymphatic system from infection, inflammation, injury, cancer or cancer treatment and poor limb movement.

There is no cure for lymphoedema but the condition can be managed by stimulating the flow of lymph fluid through exercise, compression garments and massage techniques. If left untreated the condition can lead to complications such as cellulitis.

  • Lymphoma

The two main types of lymphoma are non-Hodgkin and Hodgkin lymphoma. They are cancers of the lymphatic system. The difference between these two subcategories of lymphoma is down to the lymphocytes or white blood cells that are involved.

Treatment pathways will depend on the specific type of lymphoma. In some cases the condition may be initially monitored for some time before treatment is commenced.

How to keep the lymphatic system healthy

Keeping fit and healthy can help maintain a functioning lymphatic system.

Regular exercise can provide many health benefits. It can also help to move lymph around the system and potentially reduce any swelling that is present.

If you have been diagnosed with lymphoedema you should speak to your doctor before you commence a new exercise regime. Manual lymphatic drainage (MLD) is a specialised massage technique to help reduce fluid build up in certain cases of lymphoedema.

Certain sitting positions, lying positions and deep breathing techniques may help the lymphatic system to drain.

Maintaining good hygiene, looking after your skin and getting to know your own body can also be important, as doing so can help you to notice any irregularities such as swelling.

It is important to seek medical advice if:

  • you notice a swollen lymph node that appears to be hard or fixed in place;
  • you come across a node that appears swollen for longer than one or two weeks;
  • the swelling is accompanied by a fever, unexplained weight loss or night sweats.