Macrophage is-
The monocytes migrate to tissues and become part of the tissue (fixed) macrophages.
Blood macrophages → Monocytes
Tissue macrophages → Histiocytes Tissue macrophages (histiocytes) in different tissue are mentioned below –
Lung: ‘Alveolar macrophages’ or ‘Dust’ cells
Placenta: Hoffbauer cells
Brain: Microglia
Kidney: Mesangial cells
Liver: Kupffer cells
Spleen: Littoral cells
Bone: Osteoclasts
Synovium: Type-A lining cells
Skin: Langerhans cells
Spleen: Red pulp sinusoidal lining cells
Connective tissue: Histiocytes (tissue macrophages)
Lifespan of monocytes in circulation is 1-3 days whereas tissue macrophages have life span of 3 months to years
Monocytes
Eosinophils
Neutrophils
Lymphocytes