Blood Corpuscles (White Blood Cells)

White Blood Cells (Leukocytes)


  • Count 4000 – 8000 per mm3
  • Have nucleus, amoeboid in shape.
  • Increase in the number of WBCs at the cost of RBCs is called Leukemia.
  • Abnormal decrease in the number of WBCs is called Leukopenia.

Production & death

  • Produced in red bone marrow, lymph nodes & some time in liver & spleen.
  • Average life about 2 weeks.
  • Destroyed in the same manner as RBCs.
  • Some (Neutrophils) live for only a few hours & 125 billion neutrophils produced each day.


  • Phagocytosis – Engulfing bacteria a defensive mechanism against bacteria.
  • Inflammation – Reaction of tissue to injury to localize invasion of germs such as local
    heat, redness, swelling, pain etc.
  • Formation of antibody – Kill germs or poisons from them (vaccination) by the
    production of antitoxins.

Special features

  • Diapedesis – WBCs can squeeze out through walls of the capillaries to injured tissue to
    fight against disease causing germs & also destroy damaged cells.
  • Pus cells are manly WBCs with tissue cells destroyed by the bacteria.
  • Better known as white cells not white blood cells because spend most of their time in tissue
    fluid & lymph (90%)& a very little time in blood (10 %)
  • Abnormal increase in number of WBCs (50,000 per mm3) indicates an infection in the body.