the blood

• the blood consists of..

  4 parts
• what are the 4 parts of the blood?

  • plasma
  • red blood cells
  • white blood cells
  • platelets
• what is the role of the plasma?

  to transport dissolved substances around the body
• what 3 things does the plasma transport?

  • soluble digestion products, eg glucose , from the small intestine and other organs
  • carbon dioxide (by aerobic respiration)
  • waste product urea, from the liver to the kidneys to be excreted in urine
• what is the role of red blood cells?

  to transport oxygen from the lungs to the body cells
• how are red blood cells adapted for their role?

  • contains oxygen-carrying molecule haemoglobin
  • no nucleus - more space for haemoglobin
  • dimples (biconcave disc) for greater surface area for diffusion of oxygen
• what is the role of white blood cells?

  they form part of the immune system
• how are white blood cells adapted for their role?

  • making antibodies
  • contains nucleus - containing DNA encodes instructions they need to do their job
• what are and what is the role of platelets?

  tiny fragments of cells to help the blood clot
• what are the uses in medicine of donated blood?

  • to replace blood lost during injury
  • some people are given platelets extracted from blood to help clotting
  • proteins extracted from blood can be useful for making antibodies
• cautions of donating blood

  • in blood transfusion we have to make sure donated blood is the same blood type as the patients
  • otherwise, the body's immune system will reject the blood and the patient could die
• risks of donated blood and how to prevent it

  • risk of diseases transmitted via blood
  • in the UK blood is screened for infections so there is a low risk