PATHOLOGY

Detailed explanation-1: -In the bone marrow, the tissue-resident macrophages are called “osteal macrophages”, which is believed to be mainly derived from mononuclear cells in peripheral blood.

Detailed explanation-2: -Osteoclasts have been traditionally viewed as the resident macrophages in the bone. In recent years, a large population of bone-resident macrophages has been identified in the periosteal and endosteal tissues. These macrophages are termed osteomacs, and comprise about one-sixth of all cells in the bone marrow.

Detailed explanation-3: -Furthermore, bones and bone marrow contain three unique macrophage populations, namely: osteoclasts and bone marrow macrophages (erythroid island macrophages), hematopoietic stem cell macrophages, and a newly-discovered group of macrophages called osteal macrophages or “osteomacs” (16).

Detailed explanation-4: -Osteoclasts. Osteoclasts are large multinucleated phagocytic cells derived from the macrophage-monocyte cell lineage (23). They migrate from bone marrow to a specific skeletal site.

Detailed explanation-5: -Depending on which organs they reside, some TRMs have specific names, such as alveolar macrophages (AMs) (lung), microglia (brain), Kupffer cells (liver), renal macrophages (kidney), and osteoclasts (skeletal system).