Lymph
Lymph is a vital fluid in the body that plays a significant role in the immune system and fluid balance. It is formed when interstitial fluid, which bathes cells in oxygen and nutrients, enters the lymphatic system after most of it is reabsorbed into the bloodstream. This milky fluid carries cellular debris, minerals, proteins, and pathogens, vital for the body’s defense against illness. The lymphatic system consists of a network of vessels and lymph nodes that filter lymph, where immune cells like lymphocytes and macrophages work to eliminate harmful agents, including cancer cells and infections.
Disorders related to lymph can arise when this system becomes compromised. Conditions like lymphedema, which leads to fluid accumulation and swelling, can occur due to congenital issues or surgical interventions that remove lymph nodes. Additionally, infections such as filariasis can damage lymphatic vessels or cause severe swelling, while lymphadenitis and acute lymphangitis are inflammatory responses to pathogens affecting lymph nodes and vessels. Understanding the structure and function of lymph and the lymphatic system highlights its essential role in health and disease management.
Subject Terms
Lymph
Biology
Anatomy or system affected: Blood, circulatory system, immune system, lymphatic system, spleen
Definition: A milky fluid that carries cellular waste, nutrients, and pathogens for processing in the lymphatic system
Structure and Functions
Blood flows from the heart through smaller and smaller arteries until it reaches capillaries. There the plasma (blood without red blood cells) oozes into the surrounding tissue, bathing the cells in oxygen, nutrients, and hormones. About 90 percent of this tissue fluid (also known as intercellular fluid or interstitial fluid) is absorbed back into the blood system via the veins. The remaining 10 percent enters the lymphatic system, and this is the milky fluid known as lymph. It carries with it cellular debris, minerals, proteins, and pathogens, such as viruses, bacteria, and cancer cells.
The lymphatic system is a network of vessels, similar to blood vessels and lymph nodes. At some point, lymph passes through one of the hundred lymph nodes in the body, where it is cleansed of debris. White blood cells, primarily lymphocytes and macrophages, attack cancer cells and cells infected by microorganisms. Lymph, therefore, helps the immune system combat disease. The lymphatic system also plays a role in balancing the body’s fluid load. Lymph exits the lymphatic system at the subclavian veins at the base of the neck, reentering the blood.
Disorders and Diseases
Problems associated with lymph arise when the lymphatic system fails to circulate it or when the fluid carries pathogens that cause an infection in the system. Lymphedema is the accumulation of lymph, which causes swelling. Congenital lymphedema is caused by an inadequate number of lymph vessels. It results in swelling in the legs. The more common acquired lymphedema is usually the result of major surgery that involves the removal of lymph nodes—as occurs, for instance, during surgery for breast cancer. Filariasis, a parasitical infection, can cause scarring and constriction in the lymphatic vessels and lymphedema. It may so distend the legs that they look like elephant legs, a rare condition known as elephantiasis.
Lymphadenitis is the inflammation of lymph nodes by a pathogen, typically bacteria or viruses, spread from the skin or an orifice. Similarly, acute lymphangitis involves inflamed lymph vessels because of bacteria, usually streptococcus, in the skin.
Bibliography
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