The normal components of lymph include white blood cells and a clear intestinal fluid containing proteins and fats. The lymph system is a major part of the body's immune system.
The lymph system carries fluid, nutrients and waste throughout the body's tissues and into the bloodstream. Lymph nodes, small, bean-shaped organs, produce immune cells that help the body fight infection, according to the National Institutes of Health. These cells are located in the neck, groin and underarm regions and generally cannot be felt under the skin. The lymph nodes filter the lymph fluid, trapping bacteria, viruses and other foreign particles inside. The immune cells, known as lymphocytes, then destroy the harmful particles.
During times of injury or infection, the lymph nodes can swell in certain areas. The location of the swollen lymph node can help identify the type of infection impacting the body, notes WebMD. For example, glands in the neck swell when a person has a cold or sore throat. They can also swell when a tumor occurs in the head, mouth or neck. Glands in the underarm swell due to injury or infection in the arm or hand. Swelling of these glands may also indicate breast cancer or lymphoma.