Lymph is a clear-to-white fluid that is part of the lymphatic system, which is a network of organs, lymph nodes, lymph ducts, and lymph vessels that make and move lymph from tissues to the bloodstream. The lymphatic system is a major part of the bodys immune system. Lymph is made of white blood cells, especially lymphocytes, which are the cells that attack bacteria in the blood and body tissues, and fluid from the intestines called chyle, which contains proteins and fats. Lymph nodes are small, round- or bean-shaped structures located in clusters in various parts of the body, such as the neck, armpit, groin, and inside the center of the chest and abdomen. They mainly store immune cells that help the body fight infection but are also places where these cells can be made. They also filter the lymph fluid and remove foreign material such as bacteria and cancer cells. When bacteria are recognized in the lymph fluid, the lymph nodes make more infection-fighting white blood cells, causing the nodes to swell. The swollen nodes are sometimes felt in the neck, under the arms, and groin.

The lymphatic system is responsible for maintaining fluid levels in the body tissues by removing all fluids that leak out of our blood vessels. It also reacts to bacteria, deals with cancer cells, and deals with cell products that otherwise would result in disease or disorders. The lymphatic system includes organs such as bone marrow, thymus, spleen, tonsils, and adenoids. Lymph nodes are small structures that work as filters for foreign substances, such as cancer cells and infections. They contain immune cells that can help fight infection by attacking and destroying germs that are carried in through the lymph fluid. Swollen lymph nodes are a sign of common infections, like strep throat, but also more serious diseases like cancer.