The lymphatic system is a network of organs, tissues, vessels, and channels throughout the body that help filter and remove excess fluids and impurities.
It also plays an important role in producing defense cells, such as lymphocytes, which protect the body by fighting microorganisms that can cause disease.
To keep the lymphatic system healthy and help prevent illness, it’s important to avoid exposure to chemicals such as pesticides and cleaning products, drink plenty of water, eat a balanced diet, and exercise regularly.
Main functions
The main functions of the lymphatic system include:
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Collecting and filtering excess fluid through lymph and transferring it back into the blood
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Absorbing fats from the intestines and transporting them to the blood, supporting lymphocyte production and immune system development
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Transporting and removing waste products and damaged cells from the body
As a vital part of the immune system, the lymphatic system produces and releases lymphocytes and other defense cells that fight bacteria, viruses, parasites, and fungi. This helps prevent many conditions, including cancer, flu, and colds.
What is lymphatic drainage?
Lymphatic drainage is a massage technique that uses gentle hand movements to stimulate and improve the flow of lymph through its vessels, helping it reach the bloodstream more quickly.
Because the lymphatic system does not have its own pump like the heart, this massage can assist with lymph return, especially in people with fragile vessels or a tendency to retain fluid. It can help reduce swelling in the face or body.
Anatomy of the lymphatic system
The main components of the lymphatic system are:
1. Lymph
Lymph is a clear fluid made up of water, nutrients, and substances produced by cells, such as hormones and enzymes, that circulates through the lymphatic system.
Function: lymph drains excess water and waste from the body and transports white blood cells throughout the body to help fight infections.
2. Lymphatic vessels
Capillaries are small, thin lymphatic vessels that collect lymph. As they move toward the heart, they increase in size and form larger lymphatic vessels.
Function: capillaries and lymphatic vessels collect and transport lymph to be filtered in the lymph nodes. After filtration, the vessels release the lymph into the thoracic ducts, which extend from the abdomen to the neck.
3. Lymphatic ducts
These are large channels known as the left and right lymphatic ducts, where lymphatic vessels empty filtered lymph. These ducts connect to the heart, allowing lymph to pass before returning to the bloodstream.
Function: the thoracic duct collects and carries most of the lymph in the body into the blood, helping maintain normal blood volume and blood pressure, and preventing fluid buildup (edema).
4. Lymphatic organs
Lymphatic organs are located along the lymphatic vessels and are activated during infection or inflammation. The main lymphatic organs are:
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Bone marrow: soft, spongy tissue inside long bones, such as the hip and sternum, responsible for producing red blood cells, white blood cells, and platelets
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Thymus: a gland in the upper chest that develops and multiplies T lymphocytes, which help fight microorganisms, especially during early life
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Spleen: the largest lymphatic organ, located in the upper left abdomen above the stomach, which produces lymphocytes, filters blood, and removes microorganisms and aged cells
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Appendix: contains lymphoid tissue that helps fight bacteria before they reach the intestines and may store beneficial bacteria to restore gut balance after infection
Other lymphatic structures include the tonsils, clusters of lymph nodes in the throat, and Peyer’s patches in the intestines. Both help produce immune cells and protect against microorganisms.
5. Lymph nodes
Lymph nodes are small glands located in the armpits, groin, and neck. They filter lymph by removing bacteria, viruses, and cancer cells, and also produce and store lymphocytes and other immune cells that fight microorganisms in the lymph.
Main diseases of the lymphatic system
Several conditions can affect the lymphatic system and lead to disease, including:
1. Filariasis
Filariasis, also called elephantiasis, is caused by the parasite Wuchereria bancrofti, which is transmitted to humans by mosquito bites from the Culex species.
The parasite invades the lymphatic vessels and blocks lymph flow, causing swelling in the affected area.
2. Cancer
Certain cancers can affect the lymphatic system, such as lymphoma, in which lymphocytes multiply abnormally. This disrupts lymph flow and causes tumors, leading to symptoms like fatigue, itching, and weight loss.
Other cancers may also block lymphatic channels, interfering with circulation.
3. Allergies
Allergies are reactions to substances like dust, pollen, or cigarette smoke. They can trigger conditions such as allergic rhinitis, asthma, conjunctivitis, and dermatitis.
In these cases, the immune system produces more defense cells to fight the substances, leading to inflammation and symptoms such as sneezing, runny nose, nasal congestion, and breathing difficulties.
4. Enlarged lymph nodes
Lymph nodes may become enlarged due to infections like pharyngitis, mononucleosis, or HIV, or in response to cancer.
Lymphadenitis is inflammation caused by microorganisms in the lymph nodes, which then become swollen and tender.
5. Lymphatic malformations
Abnormalities in lymphatic vessels or nodes can impair circulation. This may lead to lymphedema, a swelling caused by the accumulation of lymph and fluid in the body.
6. Injuries to lymphatic organs
Injuries to lymphatic organs such as bone marrow, spleen, or lymph nodes, caused by trauma or certain medications, can interfere with lymph circulation.
Women undergoing breast cancer treatment with radiation therapy or lymph node removal in the armpit may experience reduced lymph drainage.
When to see a doctor
It’s important to see a doctor if you have extreme fatigue, swelling that lasts a long time without an apparent cause or interferes with daily activities, unexplained weight loss, or fever.