Lymph from the pelvic and abdominal cavities passes through many lymph nodes before entering the cisterna chyli. The abdominal and pelvic nodes are situated mainly in association with the blood vessels supplying the organs and close to the main arteries, i.e. the aorta and the external and internal iliac arteries. The lymph from the lower limbs drains through deep and superficial nodes including popliteal nodes and inguinal nodes. Functions of lymph nodes Filtering and phagocytosis Lymph is filtered by the reticular and lymphoid tissue as it passes through lymph nodes. Particulate matter may include microbes, dead and live phagocytes containing ingested microbes, cells from malignant tumours, worn out and damaged tissue cells, and inhaled particles.
Organic material is destroyed in the lymph nodes by macrophages and antibodies.
Some inorganic inhaled particles cannot be destroyed by phagocytosis. These remain inside the macrophage either causing no damage or destroying it. Material not filtered off and dealt with in one lymph node passes on to the next and so on. Thus by the time the lymph reaches the blood it has usually been cleaned of all impurities such as cell debris and foreign bodies. In some instances where phagocytation is incomplete the node may swell.