White blood cells are known as leukocytes. These are cells that are manufactured by the body in the bone marrow. They form part of the blood and help the body fight infection. They number from seven to twenty five thousand per drop of blood in a healthy human being. White blood cells are broadly classified into either Granulocytes or Agranulocytes; which are further divided into types. When a disease breaks out within the body it is these white blood cells that attack it; they either produce antibodies to fight the disease or surround and devour it. They can even increase in number to fend of a resistant disease. Types of white blood cells include neutophils (fights bacteria), Eosinoophil (fights parasites), basophil (releases histamine to tackle allergies), Lymphocytes (includes B cells, T Cells and Natural Killer Cells), Monocyte and Macrophages.
