lymphe

Lymphe is the clear to pale yellow fluid that circulates through the lymphatic system. It originates from interstitial fluid that bathes tissues and is collected by microscopic lymphatic capillaries. The fluid is then transported through progressively larger lymphatic vessels and eventually drains into the venous bloodstream.

The lymphatic system consists of lymphatic vessels, lymph nodes, and lymphoid organs such as the spleen and thymus. Lymphatic capillaries have closed ends and are highly permeable, allowing proteins, lipids, and immune cells to enter. Valves and smooth muscle in larger vessels help propel lymph, while muscle movement and breathing also aid drainage.

Functions include immune surveillance, transport of lymphocytes and antigen-presenting cells, and removal of cellular debris and waste. In the small intestine, specialized lymphatic vessels called lacteals absorb dietary fats, forming chyle. Lymphe helps maintain tissue fluid balance by returning filtered fluid to the bloodstream.

Within lymph nodes, lymph is filtered and exposed to immune cells, enabling responses to pathogens. Other lymphoid organs—such as bone marrow, thymus, spleen, and tonsils—contribute to lymphocyte development and immune function. Lymphe movement can be affected by disease or injury; impaired drainage can cause lymphedema.

Clinically, the lymphatic system serves as a route for cancer metastasis, especially to regional lymph nodes. Lymphedema may arise from congenital abnormalities, surgery, radiation, infection, or injury, and requires management to reduce swelling and infection risk.