lymph vessels

• not all tissue fluid re enters the capillaries at the venule end of the capillary bed - some excess tissue fluid is left over and eventually gets returned to the blood through the lymphatic system

  ( drainage system made up of lymph vessels )
• the smallest lymph vessels are lymph capillaries
• excess tissue fluid passes into lymph vessels. once inside its called lymph
• valves in the lymph vessels stop the lymph going backwards
• lymph gradually moves towards the main lymph vessels in the thorax. here its returned to the blood, near the heart
• 1. the smallest lymph vessels are lymph capillaries
  2. excess tissue fluid passes into lymph vessels. once inside its called lymph
  3. valves in the lymph vessels stop the lymph going backwards
  4. lymph gradually moves towards the main lymph vessels in the thorax. here its returned to the blood, near the heart
• label the diagram

  A) valve

  B) capillary containing blood

  C) red blood cells

  D) blood to heart

  E) blood from heart

  F) lymphatic vessel

  G) tissue fluid

  H) lymph

  
• blood :

  contains - red blood cell, white blood cell, platelets, proteins, water, dissolved solutes
• tissue fluid: contains - very few wbc, very few proteins, water and dissolved substances
• lymph: contains - wbc, antibodies, water, dissolved substances
• red blood cells - too big to get through capillary walls into tissue fluid
• white blood cells - most are in the lymph system and only enter tissue fluid when theres infection
• platelets are only present in tissue fluid if capillaries are damaged
• most plasma proteins are too big to get through capillary walls
• tissue fluid and lymph have a higher water potential than blood
• solutes ( e.g. salt ) can move freely between blood, tissue fluid and lymph