2. Lymphatic System Anatomy and Physiology

3. Lymphatic System Network of vessels Transports excess fluid from around the cells to the bloodstream Lymph capillaries merge into larger lymph vessels

4. Lymphatic System Pathway: Lymphatic capillary to lymphatic vessel to lymph node to lymphatic vessel to lymphatic trunk to collecting duct to subclavian vein

5. Lymphatic System The two large collecting ducts return fluid to the subclavian veins Lymph capillaries are one cell thick Lymph vessels are similar to veins: thin walls, with valves

6. Lymphatic System How does the fluid form? Water and dissolved substances leave the blood capillaries by diffusion and filtration Picked up by the lymph capillaries Inner body

7. Lymphatic System Lymph nodes: are located all along the pathway Contain lymphocytes and macrophages that fight invading pathogens

8. Lymph Nodes

9. Lymphatic System Thymus and spleen are also lymph organs Thymus is large in early life, then shrinks after puberty It matures T cells Spleen is like a giant lymph node; filters blood and fights infection