lymph

• How does lymph form?

  some tissue fluid re-enters the capillaries while some enters the lymph vessels

  the lymph vessels are separate from the circulatory system, they have closed ends and large pores that allow large molecules to pass through

  larger molecules that can’t 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
• How does liquid move along the lymph vessels?

  compression caused by body movement/ muscle contraction

  any back flow is prevented by valves

  this is why people who have been sedentary on planes can experience swollen lower limbs
• The lymph eventually re-enters the bloodstream through veins located close to the heart

  any plasma proteins that have escaped from the blood are returned to the blood via lymph capillaries