The lymphatic system runs throughout the body in parallel to the venous system. It consists of lymph vessels and lymphatic organs. The lymphatic system drains and purifies excess fluids and balances the amount of fluids circulating in the body.
What is the lymphatic system?
How does the lymphatic system work?
The lymphatic pathway begins with the smallest lymphatic vessels, the lymph capillaries, which are blind end tubes without valves. The lymphatic capillaries collect fluid from the spaces between the tissue. As soon as the fluid is taken up by the lymphatic capillaries it’s called lymph. The lymphatic capillaries form a large network throughout the body and merge into pre-collector and collector vessels.
The lymph then travels a long way through the body to the lymph nodes and to the lymphatic ducts before flowing into the venous system. Different mechanisms exist to transport the lymph throughout the body and back into the blood circulation:
- Lymphatic valves: these structures act like one-way streets to direct the lymph into one direction
- Skin and fascia movement: muscle contraction squeezes the lymph vessels together
- Bowel movement: regular movement of the intestines supports the lymphatic transport
- Pulsation from the arteries: arteries running parallel to the lymphatic system also promote the lymphatic transport
- Breathing: inhaling and exhaling create a suction effect
Manual Lymphatic Drainage (MLD) and compression therapy are external ways to support the lymph transport.
Functions of the lymphatic system
The lymphatic system has an important role in the immune system, in lipid (fat) absorption and water balance:
- Immune system: The lymphatic system helps fight infection. It produces and releases white blood cells, also called lymphocytes, that defend the body against bacteria or viruses, among others.
- Lipid absorption: The lymphatic system also absorbs lipids from the gut and transports them to the blood.
- Water balance: The lymphatic system maintains the body's fluid levels by collecting, filtering, and returning fluid from all over the body.
Lymphedema
What happens when the lymphatic system doesn’t work properly? Damage to the lymphatic system causes an accumulation of lymph fluid. This, in turn, results in swelling of the affected area (most often in the arms or legs). This swelling is called lymphedema and can result from primary (genetic) or secondary (due to other diseases or injuries) causes. Lymphedema is a long-term (chronic) disease that requires life-long treatment. You can read more about lymphedema here.
