Normal lymphatic system. Coloured lymphogram (X-ray) of a section through the abdomen of a healthy 26-year-old, showing the normal appearance of the para-aortic lymph nodes (white blotches, left and right) - a group of lymph nodes that lie in front of the lumbar spine, near the aorta. The lymphatic system functions to drain fluid (lymph) from body tissues and also plays a vital role in the body's immune system. Lymph nodes are responsible for collecting and destroying bacteria and viruses.