The Blood

• Components of blood


  • Red blood cells
  • White blood cells
  • Plasma
  • Platelets
• Blood plasma


  1. Transports carbon dioxide produced by aerobic respiration from the organs to the lungs to be breathed out

  2. Transports waste product urea from the liver to the kidneys to be excreted in urine
• Red blood cells

  • Transport oxygen from the lungs to the body
  • Do not contain a nucleus so they can contain more haemoglobin
  • Are small and flexible to fit through narrow blood vessels
  • Have a biconcave shape to maximise surface area for oxygen absorption
  • Have very thin cell membranes to allow oxygen to diffuse out quickly
• White blood cells


  • Form the immune system by making antibodies
  • Contain a nucleus with DNA that instructs them to do their job
• Platelets


  • Are tiny fragments of cells
  • Contain proteins on their surface that allow them to stick to breaks in the blood vessel wall and to each other
  • Contain granules that are critical to stop bleeding and seal the blood vessel wall
• Plasma


  • Is the straw coloured liquid part of blood
  • Carries out all the other components of blood
  • Dissolves glucose for energy and waste products like carbon dioxide
  • Transports all the other parts of blood
• Platelets are tiny fragments of cells
• White blood cells contain a nucleus with DNA that instructs them to do their job
• Plasma carries out all the other components of blood
• Plasma dissolves glucose for energy and waste products like carbon dioxide
• Plasma transports all the other parts of blood