|Lymph is a clear fluid that is very similar to blood plasma, the clear liquid in blood, but it carries only white blood cells, not red blood cells.|
|The lymph flows through all the parts of the body picking up fluid around cells and carrying it back to large veins near the heart. It also carries white blood cells to the places that they are needed.|
|Some bacteria or viruses that have entered the body are collected by the lymph and passed on to the lymph nodes where they are filtered out and destroyed. Lymph nodes are sometimes called glands.|
Your doctor can often tell if you have an infection by checking out the lymph nodes (glands) in your neck and under your arms to see if they're swollen. If they are, it shows that they are working to get rid of bacteria or viruses.
Read more at Women's and Children's Health Network: The immune system