Our bodies have more than 600 small, kidney bean-shaped lymph nodes. The lymph nodes, also known as lymph glands, help the body fight off infections. Inside the lymph nodes is a combination of various types of immune system cells, which act as waste filters for dead and damaged cells. They also trap viruses and bacteria before they infect other parts of the body. Swollen lymph nodes can often be felt or noticed on the neck, in the middle of your chest or belly, in the armpits, or in the groin area.