Blood

Cards (5)

  • Blood is a tissue
  • Red blood cells carry oxygen from the lungs to all the cells in the body.
    • They are shaped as a biconcave disc, this gives them a large surface area for absorbing oxygen
    • They don't have a nucleus- this allows more room to carry oxygen
    • They contain a red pigment called haemoglobin
    • In the lungs haemoglobin binds to oxygen to become oxyhaemoglobin. In body tissues the reverse happens to release oxygen into the cells.
  • White blood cells defend against infection
    • Some change shape to engulf unwelcome microorganisms in a process called phagocytosis
    • Others produce antibodies to fight microorganisms, as well as antitoxins to neutralise any toxins produced by the microorganisms
    • Unlike red blood cells they do have a nucleus
  • Platelets help blood clot
    • These are small fragments of cells with no nucleus
    • When wounds occur they stop blood pouring out and microorganisms coming in
    • Lack of platelets can cause excessive bleeding and bruisinh
  • Plasma is the liquid that carries everything
    • It is a pale straw-coloured liquid which carries:
    • Red and white blood cells
    • Platelets
    • Nutrients
    • Carbon dioxide
    • Urea from the liver to the kidneys
    • Hormones
    • Proteins
    • Antibodies and Antitoxins