blood

• 4 parts of human blood?

  plasma, RBC, WBC, platelets
• what is plasma?

  transports dissolved substances around the body
• what things does plasma transport?

  1. digestion products like glucose from small intestines to other organs
  2. CO2 from organs to the lungs to be breathed out
  3. urea from liver to the kidneys to be excreted in urine
• what is CO2 produced by?

  aerobic respiration
• role of RBC?


  carry O2 from the lungs to the body cells
• adaptations of the RBC:

  1. contain haemoglobin which combines with O2 -> oxyhaemoglobin which is releases o2 in the body
  2. no nuclues so more room for haemoglobin
  3. biconcave shape - gives large SA so O2 diffuses in and out rapidly
• what are WBC?


  fight off pathogens
• Adaptations of WBCS:

  1. contain nucleus which contains DNA that instructs when WBC'S need to do their job
• role of platelets?


  tiny fragments of cell that help blood to clot
• how is donated blood used in medicine?

  • to replace blood loss
  • given platelets to help with clotting
  • protein extracted from blood for antibodies
• problems with donated blood:

  1. need to be the same blood type - immune system will reject
  2. lots of diseases passed on - blood can be screened so risk is low