Macrophage is -
High-Yield Explanation
Ans. is 'a'i.e., Monocytes o The monocytes migrate to tissues and become part of the tissue (fixed) macrophages.o Blood macrophages - Monocyteso Tissue macrophages - HistiocytesTissue macrophages (histiocytes) in different tissue are mentioned below -o Lung: 'Alveolar macrophages' or 'Dust' cellso Placenta: Hoffbauer cellso Brain: Microgliao Kidney : Mesangial cellso Liver : Kupffer cellso Spleen : Littoral cellso Bone: Osteoclastso Synovium: Type-A lining cellso Skin: Langerhans cellso Spleen: Red pulp sinusoidal lining cellso Connective tissue: Histiocytes (tissue macrophages)o Life span of monocytes in circulation is 1-3 days whereas tissue macrophages have life span of 3 months to years