Lymphatic system and lymphatic tissue
Apart from the blood circulatory system, there is yet another vascular system in the body – the lymphatic system. It branches out via thin vessels – similar to the arteries – throughout the entire body. In the lymphatic vessels there is a colorless, watery liquid containing white blood corpuscles. This elaborate closed "circulation system" connects to each other special bean-sized glands, called "lymph nodes," which filter the blood and destroy foreign invaders. Apart from lymph nodes, other lymphatic tissue is located along the lymphatic vessel routes: the spleen, the thymus, the tonsils and others.
It is a fascinating network which protects us from all sorts of invading germs and parasites: In the lymphatic tissues certain kinds of white blood corpuscles are stored and mature. They wait for deployment as a defense troop when pathogens pose a danger. Without this lymph system, we would soon die of overwhelming infection.
A complex variety of cancers can arise within this system, called "lymphomas." In the so-called “Hodgkin’s disease” the white corpuscels develop into giant cells, an indication that their growth and their genetic programs have gotten out of control.
