blood group, vessels and functions

• Blood groups


  Different types of antigens and antibodies present in blood
• Blood groups


  • A
  • B
  • AB
  • O
• Blood group A


  • Red blood cells possess antigen A
  • Plasma contains antibody b
• If you belong to blood group A

  Your plasma could not contain antibody a, or your own red blood cells would agglutinate
• Antigens and antibodies in different blood groups


  • Blood group A: antigen A, antibody b

  Blood group B: antigen B, antibody a

  Blood group AB: antigens A and B, no antibodies

  Blood group O: no antigens, antibodies a and b
• Universal donor


  Blood group O, as the red blood cells do not have antigens A and B
• Universal acceptor


  Blood group AB, as it has no antibodies
• When different blood groups are mixed in a transfusion


  Clumping or no clumping can occur depending on the antigens and antibodies present
• When you donate whole blood, it is usually separated into its components (e.g. red blood cells, plasma, platelets) for transfusion
• Most of the time, only the donor's red blood cells are transfused to the recipients
• Arteries


  • Carry blood away from the heart
  • The large artery leaving the left side of the heart is the aorta
• Arterioles


  • Tiny vessels that divide to form capillaries
• Capillaries


  • Microscopic blood vessels found between cells
  • Walls made of a single layer of flattened cells
  • Partially permeable to allow exchange of substances
• Venules


  • Small vessels that blood capillaries unite to form before leaving an organ or tissue
• Veins


  • Carry blood back to the heart
• When an arteriole branches into many capillaries

  The total cross-sectional area of the blood vessels increases, lowering the blood pressure and slowing down the flow of blood to allow more time for exchange of substances