An amazing thing about lymph is that everyone has it but we generally know nothing about it. The entire body is soaked in lymph and bodies have a whole lymph vessel system just as complex as the blood vessels.
Capillaries do not connect to cells but instead flow past them. Clear and watery blood plasma - containing oxygen, proteins, glucose and white blood cells - leaks through capillary walls and flows around cells. Pores in the capillaries are too small for red blood cells to get through. That is why lymph is clear rather than red. Lymph bathes all the cells in the body. The cells receive their nutrients and oxygen from lymph.
Somehow, all this lymph has to end up somewhere. Therefore, it is re-circulated. Lymph capillaries and vessels pick up the lymph fluid to start pumping it away from cells. Lymph vessels do not have a pump like the heart. Instead, the lymph vessels have one-way valves. Muscle motion pumps the lymph.
Lymph in the lymph vessels eventually will reach a lymph node. There are about 100 nodes scattered throughout the body. These lymph nodes filter the lymph and contain large numbers of white blood cells, which remove foreign cells and debris from the lymph. If you get certain infections, lymph nodes swell with billions of white blood cells that are working to clear the foreign cells causing the infection. Filtered lymph then flows back into the blood.
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