The lymph capillaries are separate from the circulatory system They have closed ends and large pores that allow large molecules to pass through Larger molecules that are not able to pass through the capillary wall enter the lymphatic system as lymph Small valves in the vessel walls are the entry point to the lymphatic system

Lymphopenia is a condition when there are too few white blood cells called lymphocytes in your blood. A lymphocyte is just one type of white blood cell. About 20% to 40% of your white blood cells are lymphocytes. These white blood cells help your body fight germs that can make you sick, including viruses, bacteria, parasites and fungi.

What are lymph nodes? Lymph nodes are critical parts of the immune system. They filter foreign substances from the body and store white blood cells called lymphocytes. Lymphocytes fight disease.