lymphatic system

• the walls of capillaries are so thin that water, dissolved solutes and gases easily leak out/pass through them - from the plasma, into the tissue fluid that surrounds the cells.
• cells exchange material go across their cell membranes with the tissue fluid surrounding them by diffusion, osmosis or active transport
• • more fluid leaks out of the capillaries
  • less fluid is returned to the capillaries - excess fluid passes into the lymphatic system and becomes lymph fluid
• the lymphatic system is formed from a series of tubes which flow from tissues back to the heart
• the lymphatic system connects with the blood system near the heart, where lymph fluid is returned to the blood plasma
• lymph nodes: small clusters of lymphatic tissues found throughout the lymphatic system, especially in the neck and armpits
• • there are large numbers of lymphocytes in lymph nodes
  • tissues associated with the lymphatic system (like bone marrow) produces the lymphocytes
  • lymphocytes defend the body against infection