Unit 5 biology

• Blood has 4 main components

  Plasma

  red bloods cells

  platelets

  white blood cells
• plasma

  Plasma is pale yellow liquid

  Plasma carries:

  red blood cells, white blood cells and platelets

  digested food products

  carbon dioxide

  urea

  hormones

  heat energy
• platelets

  platelets clump together to plug damaged area

  blood clots stop you from loosing too much blood and prevent microorganisms from entering

  in a clot platelets are held together fibrin
• red blood cells :

  • RBC transports oxygen from the lungs to all cells in the body
  • RBC is small and has a biconcave shape to give a large surface area for absorbing and releasing oxygen
  • they contain hemoglobin which gives it its color
  • RBC don’t have a nucleus this frees up space for hemoglobin
• There are 2 types of white blood cells

  Phagocyte

  lymphocyte
• How do phagocyte work ?

  phagocytes detect things that are foreign to the body

  phagocyte then engulfs the pathogen and then enzymes digest it
• Lymphocyte (4 marks)

  • Lymphocyte produce antibodies
  • The antibodies produced are specific to that type of antigen
  • antigen are produced rapidly and flow round the body to mark similar pathogens
  • memory cells are produced in response
• Vaccination


  Injecting dead or inactive pathogens into the body

  these carry antigens

  lymphocytes produce antibodies to attack them

  memory cells will also be produced