Lymphatic system
Most of us have experienced 'swollen glands' at one time or another. But many people don't understand what glands are, or what they do.
Properly called lymph glands — or to be really accurate lymph nodes — the glands are part of a network of tiny vessels known as the lymphatic system.
This system is rather like the system of blood vessels that supplies all parts of the body. However instead of blood, the lymph vessels carry a clear, straw-coloured fluid — lymph. This fluid originates in the bloodstream and seeps through the walls of tiny blood vessels. It bathes and nourishes the body's tissues. It collects in the lymphatic vessels and eventually returns to the bloodstream.
The lymphatic system serves as one of the body's defences against infection. The lymph nodes (glands) are collections of tissue along the lymphatic vessels. They contain large numbers of cells called macrophages and lymphocytes. These cells act as scavengers, killing and removing harmful invaders such as bacteria and viruses.
When this happens the number of cells in the node increases rapidly. This may cause the node to swell, become tender and, sometimes, red.
The main areas where this is noticeable are the neck, groin and axilla (armpit). Thus an infected finger might result in swollen glands in the armpit on that side. The very obvious swollen glands in the neck of a child with tonsillitis are a common sight for many parents.
The tonsils, adenoids and spleen are all organs involved in fighting infection and consist mainly of lymphatic tissue.
As well as dealing with infections, lymph glands also trap cancer cells, reducing their spread through the body.
Sometimes the lymphatic system itself is the primary target for cancer. A disease called Hodgkin's disease is a common form of this type of cancer and shows up with persistent and quite hard swollen glands.
Swollen glands are common. If they 'come and go' there is usually nothing to worry about. But if glands remain enlarged for a week or more, with no obvious cause such as a local infection, ask your doctor to look at them, in case they are a sign of something more serious.
Last Reviewed: 21 May 2002
