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Reactive lymphadenopathy
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Lymph nodes are small bean-shaped organs spread throughout the body, and they are part of the immune system, the one that defends you. When one swells, the swelling has a medical name: lymphadenopathy. Lymph nodes swell during an infection, and infections are the most common cause of that swelling.
What goes on inside explains the lump. Bacteria that infect the fluid bathing the tissues are picked up by tiny vessels, the lymphatic capillaries, and carried to the node that drains that region. That node is the site of the adaptive immune response, the defense that learns to recognize one specific enemy, and in a region called the germinal center the B lymphocytes, the cells that make antibodies, start dividing at full speed. A node like that is a barracks that has filled up with soldiers. That is why a painful node is usually a sign that the body is fighting, and why it can take several weeks to return to its normal size.
In brief
The medical name for a swollen lymph node is lymphadenopathy; infections are its most common cause, and lymph nodes swell during an infection.
Bacteria infecting tissue fluid travel through lymphatic capillaries to the regional node, where the adaptive immune response takes place and B lymphocytes divide rapidly in the germinal center.
A painful node is usually a sign that the body is fighting an infection, and it can take several weeks to return to its normal size.
Sources (2)
- MedlinePlus, U.S. National Library of MedicineSwollen lymph nodes (Medical Encyclopedia)
- OpenStax, Rice UniversityAnatomy and Physiology 2e, 21.1 Anatomy of the Lymphatic and Immune SystemsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated