Cell Type         %   Appearance        Job(s)
            
_______________________________________________________________________

1. RED BLOOD CELLS  >99 Small red.         Oxygen transport (in)
   (erythrocyte)                           CO2 and heat transfer (out)


2. WHITE BLOOD CELLS <1 Larger than
    (leucocytes)        red blood cells.   Defense of body.
                        Several different
                        cell types; all
                        with a blue-purple
                        internal nucleus.

   a. Polymorphonuclear Leucocytes
      (PMNs or polys)
      Blue-purple nucleus in several lobes
      or segments.  Each sub-type has 
      granules of a distinct colour.
       
      Sub-group      %     Granule colour   Association
      Neutrophilic  ~65    Pink             Increase in acute
                                            bacterial infections.
      Eosinophilic  1-4    Orange           These two types
                                            increase in parasitic
      Basophilic    0-0.5  Dark purple      diseases and allergies.
   

  b. Lymphocytes    20-30                   Defense of body
     Blue-purple nucleus is very            in viral infections.
     dark and fills most of the cell.
                                      
  c. Monocytes      2-6
     Blue-purple nucleus is less dense
     than in lymphocytes and sometimes
     appears "foamy" in texture and
     "horse-shoe"-shaped.

3. PLATELETS - not true cells 
     The smallest purple bodies in         Stop blood from leaking
     blood.  Consist of small,             by promoting clotting
     "pinched off" fragments of cells.     and patching leaks in
                                           blood vessels.