components of blood

• what do red blood cells carry?

  oxygen
• why do red blood cells have a large surface area?

  to absorb oxygen
• why don’t red blood cells have a nucleus?

  they have more room to carry oxygen
• what is the red pigment in red blood cells?

  haemoglobin
• what is phagocytosis?

  white blood cells changing shape to engulf unwelcome microorganisms
• what do white blood cells have that red blood cells don’t?

  a nucleus
• what are platelets?

  small fragment of cells with no nucleus. they help the blood to clot at a wound to stop blood pouring out and microorganisms getting in
• what does plasma carry?

  • red & white blood cells
  • platelets
  • nutrients eg glucose, amino acids
  • carbon dioxide
  • hormones
  • proteins
  • antibodies & antitoxins produced by the white blood cells