part of part of macrophage tissue-resident macrophage fixed macrophage FMA:84644 A macrophage constitutively resident in a particular tissue under non-inflammatory conditions, and capable of phagocytosing a variety of extracellular particulate material, including immune complexes, microorganisms, and dead cells. https://cellxgene.cziscience.com/cellguide/CL_0000864 FMA:84642 Tissue-resident macrophages refer to a heterogeneous group of specialized macrophages that permanently reside within specific tissues, performing integral functions essential to tissue homeostasis. Most tissue-resident macrophages arise from embryonic populations and self-renew. Some macrophages may also originate from circulating monocytes released from the bone marrow and differentiate into macrophages upon entering tissue. Tissue-resident macrophages are given different names depending upon the tissue in which they reside, such as Kupffer cells in the liver, alveolar macrophages in the lungs, and microglia in the brain. Tissue-resident macrophages are responsible for the phagocytosis of pathogenic substances and dead cells, serving as part of the foremost line of defense against invading microorganisms. They utilize pattern recognition receptors to identify foreign substances and function as antigen-presenting cells to induce adaptive immunity. Additionally, they produce a variety of cytokines and chemokines, signaling molecules that recruit additional immune cells to sites of infection or inflammation and regulate immune responses. In addition to their immunological roles, tissue-resident macrophages also have tissue-unique functions. In the liver, Kupffer cells play a role in iron homeostasis, while in the brain, microglia are responsible for synaptic pruning during development. In the lungs, alveolar macrophages are involved in the removal of airborne particles and debris. This underscores their significance in not only providing pathological immunity but also in maintaining the optimal function of the tissues in which they reside. " (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) resting histiocyte tissue