Phagoctes

• Phagocytose/destroy pathogens or damaged body cells (help the clean-up and repair process), made in bone marrow and can change shape to squeeze out of capillaries
• They detect chemical signals called chemokines OR cytokines and so move towards foreign particles or microbes by chemotaxis
• Neutrophils (70% of leukocytes; most abundant WBC in blood) have a multi-lobed nucleus, granular cytoplasm, and are non-dividing, and short lived (less than a day!)
• Monocytes (5% of leukocytes): Largest leucocytes, long lived, phagocytosis, fidget dead neutrophils and have a bean-shaped nucleus; some migrate through body (now called macrophages); found in lungs, brain, kidney, bone, spleen and lymph nodes
• Other leucocytes which are similar to neutrophils

  • Eosinophils (also phagocytic)
  • Basophils
  • Mast cells
  • NK (natural killer) cells

  All involved in immunity, the latter two produce large amounts of histamine when stimulated (NK cells destroy virus-infected or abnormal cells, e.g. tumour cells)