Blood

• three main functions of blood:

  • transport
  • immune defence
  • temperature regulation -
• tissue cells need glucose and oxygen for aerobic respiration- heat and carbon dioxide which are products must be removed
• blood contains plasma which contains serum - parts of blood become tissue fluid and lymph under certain circumstances
• made up of cells, platelets and plasma
• erythrocytes ( RBC ) and leukocytes ( WBC )
• platelets - fragments of cells involved in blood clotting
• red blood cells - no nucleus , haemoglobin in cytoplasm - transports oxygen
• plasma - made of fibrinogen ( clotting protein ) and serum
• serum

  90% water , glucose , amino acids , proteins , enzymes , hormones , carbon dioxide , etc
• tissue fluid - derived from blood plasma which drains blood out of carpillaries to from intermediary liquid between blood and tissue cells
• tissue fluid — bathes tissue cells and rejoins blood in capillaries or return by lymph
• lymph - milky liquid derived from tissue fluid that drains from intercellular spaces of tissues into lymph vessels